Federal Register, Volume 89 Issue 91 (Thursday, May 9, 2024)

[Federal Register Volume 89, Number 91 (Thursday, May 9, 2024)]
[Rules and Regulations]
[Pages 39686-39795]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-09054]

[[Page 39685]]

Vol. 89

Thursday,

No. 91

May 9, 2024

Part II

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Parts 571, 595, and 596

Federal Motor Vehicle Safety Standards; Automatic Emergency Braking
Systems for Light Vehicles; Final Rule

Federal Register / Vol. 89 , No. 91 / Thursday, May 9, 2024 / Rules
and Regulations

[[Page 39686]]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571, 595, and 596

[Docket No. NHTSA-2023-0021]
RIN 2127-AM37

Federal Motor Vehicle Safety Standards; Automatic Emergency
Braking Systems for Light Vehicles

AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).

ACTION: Final rule.

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SUMMARY: This final rule adopts a new Federal Motor Vehicle Safety
Standard to require automatic emergency braking (AEB), including
pedestrian AEB (PAEB), systems on light vehicles. An AEB system uses
various sensor technologies and sub-systems that work together to
detect when the vehicle is in a crash imminent situation, to
automatically apply the vehicle brakes if the driver has not done so,
or to apply more braking force to supplement the driver's braking. This
final rule specifies that an AEB system must detect and react to an
imminent crash with both a lead vehicle or a pedestrian. This final
rule fulfills a mandate under the Bipartisan Infrastructure Law (BIL)
directing the Department to promulgate a rule to require that all
passenger vehicles be equipped with an AEB system. The purpose of this
final rule is to reduce the number of deaths and injuries that result
from crashes in which drivers do not apply the brakes or fail to apply
sufficient braking power to avoid or mitigate a crash, and to reduce
the consequences of such crashes.

DATES:
Effective Date: This rule is effective July 8, 2024.
IBR date: The incorporation by reference of certain material listed
in the rule is approved by the Director of the Federal Register
beginning July 8, 2024. The incorporation by reference of certain other
material listed in the rule was approved by the Director of the Federal
Register as of July 8, 2022.
Compliance Date: September 1, 2029. However, vehicles produced by
small-volume manufacturers, final-stage manufacturers, and alterers
must be equipped with a compliant AEB system by September 1, 2030.
Petitions for reconsideration: Petitions for reconsideration of
this final rule must be received not later than June 24, 2024.

ADDRESSES: Petitions for reconsideration of this final rule must refer
to the docket number set forth above (NHTSA-2023-0021) and be submitted
to the Administrator, National Highway Traffic Safety Administration,
1200 New Jersey Avenue SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: For technical issues: Mr. Markus
Price, Office of Crash Avoidance Rulemaking, Telephone: 202-366-1810,
Facsimile: 202-366-7002. For legal issues: Ms. Sara R. Bennett, Office
of the Chief Counsel, Telephone: 202-366-2992, Facsimile: 202-366-3820.
The mailing address for these officials is: National Highway Traffic
Safety Administration, 1200 New Jersey Avenue SE, Washington, DC 20590.

SUPPLEMENTARY INFORMATION: This final rule adopts a new Federal Motor
Vehicle Safety Standard (FMVSS) No. 127 to require automatic emergency
braking (AEB), including pedestrian AEB (PAEB), systems on light
vehicles. FMVSS No. 127 applies to all passenger cars and to all
multipurpose passenger vehicles (MPVs), trucks, and buses with a gross
vehicle weight rating (GVWR) of 4,536 kilograms (kg) (10,000 pounds
(lbs.)) or less (``light vehicles''). An AEB system uses various sensor
technologies and sub-systems that work together to detect when the
vehicle is in a crash imminent situation, to automatically apply the
vehicle brakes if the driver has not done so, or to apply more braking
force to supplement the driver's braking.
This final rule specifies that an AEB system must detect and react
to an imminent crash with both a lead vehicle and a pedestrian. This
final rule advances DOT's January 2022 National Roadway Safety
Strategy, which identified a requirement for AEB, including PAEB
technologies, on new passenger vehicles as a key Departmental action to
improve vehicle and pedestrian safety. Finally, this final rule
fulfills section 24208(a) of BIL, which directs the Secretary of
Transportation to promulgate a rule to require that all passenger
vehicles be equipped with an AEB system.
NHTSA published the notice of proposed rulemaking preceding this
final rule on June 13, 2023 (88 FR 38632).

Table of Contents

I. Executive Summary
II. Background
A. The Safety Problem
B. Bipartisan Infrastructure Law (BIL)
C. High-level Summary of Comments on the NPRM
D. Summary of the Notice of Proposed Rulemaking
E. Additional Research Conducted in 2023
III. Final Rule and Response to Comments
A. Summary of the Final Rule (and Modifications to the NPRM)
B. Application
C. Definitions
D. FCW and AEB Equipment Requirements
1. Minimum Activation Speed
2. Maximum Activation Speed
3. Environmental Conditions
E. AEB System Requirements (Applies to Lead Vehicle and
Pedestrian)
1. Forward Collision Warning Requirements
a. FCW Signal Modality
b. FCW Auditory Signal Requirements
c. FCW Auditory Signal Presentation with Simultaneous Muting of
Other In-Vehicle Audio
d. FCW Visual Symbol Requirements
e. FCW Visual Signal Location Requirements
2. AEB Requirement
a. AEB Deactivation
b. Aftermarket Modifications
c. No-Contact Requirement for Lead Vehicle AEB
d. No-Contact Requirement for Pedestrians
e. Permissibility of Failure
F. False Activation Requirement
1. Need for Requirement
2. Peak Additional Deceleration
3. Process Standard Documentation as Alternative to False
Activation Requirements
4. Data Storage Requirement as Alternative to False Activation
Requirements
G. Malfunction Detection Requirement
1. Need for Requirement
2. Malfunction Telltale
3. Sensor Obstructions and Testing
H. Procedure for Testing Lead Vehicle AEB
1. Scenarios
2. Subject Vehicle Speed Ranges
3. Headway
4. Lead Vehicle Deceleration
5. Manual Brake Application
6. Testing Setup and Completion
7. Miscellaneous Comments
I. Procedures for Testing PAEB
1. Scenarios
2. Subject Vehicle Speed Ranges
3. Pedestrian Test Device Speed
4. Overlap
5. Light Conditions
6. Testing Setup
J. Procedures for Testing False Activation
K. Track Testing Conditions
1. Environmental Test Conditions
2. Road/Test Track Conditions
L. Vehicle Test Device
1. General Description
2. Definitions
3. Sideview Specification
4. Field Verification Procedure
5. Dimensional Specification
6. Visual and Near Infrared Specification
7. Radar Reflectivity
8. List of Actual Vehicles
M. Pedestrian Test Devices
1. General Description
2. Dimensions and Posture
3. Visual Properties
4. Radar Properties

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5. Articulation Properties
6. Comments on Thermal Characteristics
N. Miscellaneous Topics
O. Effective Date and Phase-In Schedule
IV. Summary of Estimated Effectiveness, Cost, and Benefits
A. Benefits
B. Costs
C. Net Impact
V. Regulatory Notices and Analyses
VI. Appendices to the Preamble
A. Appendix A: Description of the Lead Vehicle AEB Test
Procedures
B. Appendix B: Description of the PAEB Test Procedures
C. Appendix C: Description of the False Activation Test
Procedures

I. Executive Summary

In 2019, prior to the COVID-19 pandemic, there were nearly 2.2
million rear-end police-reported crashes involving light vehicles,
which led to 1,798 deaths and 574,000 injuries. In addition, there were
6,272 pedestrian fatalities in motor vehicle crashes, representing 17
percent of all motor vehicle fatalities.\1\ This represents the
continuation of the recent trend of increased pedestrian deaths on our
nation's roadways.\2\ A further 76,000 pedestrians were injured in
motor vehicle crashes. Deaths and injuries in more recent years are
even greater.
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\1\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079 Pedestrian Traffic Facts 2019 Data, May 2021.
\2\ Id., Table 1 Pedestrian fatalities 2010--4,302, 2019--6,272.
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NHTSA is issuing this final rule to address these significant
safety problems through a new Federal Motor Vehicle Safety Standard
that requires all light vehicles be equipped with forward collision
warning (FCW),\3\ automatic emergency braking (AEB), and pedestrian
automatic emergency braking (PAEB) technology.\4\ AEB systems reduce
the frequency and severity of lead vehicle and pedestrian collisions.
They employ sensor technologies and sub-systems that work together to
sense when the vehicle is in a crash imminent situation, to
automatically apply the vehicle brakes if the driver has not done so,
and to apply more braking force to supplement the driver's braking.
These systems can reduce both lead vehicle rear-end (lead vehicle AEB)
and pedestrian (PAEB) crashes. AEB systems have reached a level of
maturity to make a significant contribution to reducing the frequency
and severity of crashes and are thus ready to be mandated through
adoption of a new FMVSS on all new light vehicles.
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\3\ A forward collision warning (FCW) system uses sensors that
detect objects in front of vehicles and provides an alert to the
driver. An FCW system is able to use the sensors' input to determine
the speed of an object in front of it and the distance between the
vehicle and the object. If the FCW system determines that the
closing distance and velocity between the vehicle and the object is
such that a collision may be imminent, the system is designed to
induce an immediate forward crash avoidance response by the vehicle
operator. FCW systems may detect impending collisions with any
number of roadway obstacles, including vehicles and pedestrians.
Warning systems in use today provide drivers with a visual warning
signal, such as an illuminated telltale on or near the instrument
panel, an auditory signal, or a haptic signal that provides tactile
feedback to the driver to warn the driver of an impending collision
so the driver may intervene. FCW systems alone do not brake the
vehicle.
\4\ Hereafter, when this final rule refers to ``AEB'' generally,
unless the context clearly indicates otherwise, it refers to a
system that has: (a) an FCW component to alert the driver to an
impending collision with a forward obstacle; (b) a CIB component
that automatically applies the vehicle's brakes if the driver does
not respond to the FCW; and (c) a DBS component that automatically
supplements the driver's brake application if the driver applies
insufficient manual braking to avoid a crash. Furthermore, unless
the context indicates otherwise, reference to AEB includes both lead
vehicle AEB and PAEB.
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This rule is estimated to save at least 362 lives and mitigate
24,321 non-fatal injuries a year. It represents a crucial step forward
in implementing DOT's January 2022 National Roadway Safety Strategy
(NRSS) to address the rising numbers of transportation deaths and
serious injuries occurring on this country's roadways, including those
involving pedestrians.\5\
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\5\ https://www.transportation.gov/sites/dot.gov/files/2022-01/USDOT_National_Roadway_Safety_Strategy_0.pdf.
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The crash problem that the agency seeks to address with the AEB
requirements in this final rule is substantial.\6\ For example, 60
percent of fatal rear-end crashes and 73 percent of crashes resulting
in injuries were on roads with posted speed limits of 60 mph or below.
Similarly, most of these crashes occurred in clear, no adverse
atmospheric conditions--72 percent of fatal crashes and 74 percent of
crashes resulting in injuries. Also, about 51 percent of fatal rear-end
crashes and 74 percent of rear-end crashes resulting in injuries, all
involving light vehicles, occurred in daylight conditions. In addition,
65 percent of pedestrian fatalities and 67 percent of pedestrian
injuries were the result of a strike by the front of a light vehicle.
Finally, 77 percent of pedestrian fatalities, and about half of the
pedestrian injuries, occur in dark lighting conditions. Importantly,
this final rule requires that PAEB systems be able to avoid pedestrian
crashes in dark testing conditions.
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\6\ The Insurance Institute for Highway Safety (IIHS) estimates
a 50 percent reduction in front-to-rear crashes of vehicles with AEB
(IIHS, 2020) and a 25 to 27 percent reduction in pedestrian crashes
for PAEB (IIHS, 2022).
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This final rule is issued under the authority of the National
Traffic and Motor Vehicle Safety Act of 1966. Under 49 U.S.C. chapter
301, the Secretary of Transportation is responsible for prescribing
motor vehicle safety standards that are practicable, meet the need for
motor vehicle safety, and are stated in objective terms. The
responsibility for promulgation of FMVSSs is delegated to NHTSA. This
rulemaking addresses a statutory mandate under the Bipartisan
Infrastructure Law (BIL), codified as the Infrastructure Investment and
Jobs Act (IIJA),\7\ which added 49 U.S.C. 30129, directing the
Secretary of Transportation to promulgate a rule requiring that all
passenger motor vehicles manufactured for sale in the United States be
equipped with an FCW system and an AEB system.
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\7\ Public Law 117-58, 24208 (Nov. 15, 2021).
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The Focus on AEB

The decision to mandate AEB builds on decades of research and
development, which began in the 1990s, with initial research programs
to support development of AEB technologies and methods by which system
performance could be assessed. NHTSA began testing AEB systems as part
of the New Car Assessment Program (NCAP) in 2010 and reporting on the
research and progress surrounding the technologies shortly
thereafter.\8\ These research efforts led to NHTSA listing FCW systems
as a ``recommended advanced technology'' in NCAP in model year 2011,
and in November 2015, added crash imminent braking (CIB) \9\ and
dynamic brake support (DBS) technologies to the program.\10\ Most
recently, NHTSA proposed upgrades to the lead vehicle AEB test in its
March 2022 request for comment on NCAP.\11\
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\8\ 77 FR 39561 (Jul. 2, 2012).
\9\ This final rule does not split the terminology of these CIB
and DBS functionalities outside of certain contexts, like
discussions of NCAP, but instead considers them both as parts of
AEB. The final rule includes performance tests that would require an
AEB system that has both CIB and DBS functionalities.
\10\ 80 FR 68604 (Nov. 5, 2015).
\11\ 87 FR 13452 (Mar. 9, 2022). See https://www.regulations.gov, docket number NHTSA-2021-0002.
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In March 2016, NHTSA and the Insurance Institute for Highway Safety
(IIHS) announced a commitment by 20 manufacturers representing more
than 99 percent of the U.S. light vehicle market to include low-speed
AEB as a standard feature on nearly all new light vehicles not later
than September 1,

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2022. As part of this voluntary commitment, manufacturers are including
both FCW and a CIB system that reduces a vehicle's speed in certain
rear-end crash-imminent test conditions.
NHTSA also conducted research to understand the capabilities of
PAEB systems beginning in 2011. This work began with an assessment of
the most common pedestrian crash scenarios to determine how test
procedures could be designed to address them. As part of this research,
the agency looked closely at a potential pedestrian mannequin to be
used during testing and explored several aspects of the mannequin,
including size and articulation of the arms and legs. This work
resulted in a November 2019 draft research test procedure providing the
methods and specifications for collecting performance data on PAEB
systems for light vehicles.\12\ This procedure was expanded to cover
updated vehicle speed ranges and different ambient conditions and
included in a March 2022 request for comments notice proposing to
include PAEB, higher speed AEB, blind spot warning and blind spot
intervention in NCAP.\13\
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\12\ 84 FR 64405 (Nov. 21, 2019).
\13\ 87 FR 13452 (Mar. 9, 2022).
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Need for Regulation

While the above actions have increased market penetration of AEB
systems, reduced injuries, and saved lives, NHTSA believes that
mandating AEB systems that can address both lead vehicle and pedestrian
crashes is appropriate and necessary to better address the safety need.
NHTSA incorporated FCW into NCAP beginning in model year 2011 and AEB
into NCAP beginning in model year 2018. This has achieved success, with
approximately 65% of new vehicles meeting the lead vehicle test
procedures included in NCAP.\14\ Similarly, the voluntary commitment
resulted in approximately 90 percent of new light vehicles manufactured
in 2022 having an AEB system.
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\14\ Percentage based on the vehicle manufacturer's model year
2022 projected sales volume reported through the New Car Assessment
Program's annual vehicle information request.
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That said, the test speeds and performance specifications in NCAP
and the voluntary commitment do not ensure that the systems perform in
a way that will prevent or mitigate crashes resulting in serious
injuries and fatalities. The vast majority of fatalities, injuries, and
property damage crashes occur at speeds above 40 km/h (25 mph), which
are above those covered by the voluntary commitment.
Voluntary measures are intended to supplement rather than
substitute for the FMVSSs, which remain NHTSA's core method of ensuring
that all motor vehicles can achieve an adequate level of safety
performance. The NCAP program is designed to provide valuable safety-
related information to consumers in a simple to understand way, but the
agency believes that gaps in market penetration will continue to exist
for the most highly effective AEB systems. NHTSA has also observed
that, in the case of both electronic stability control and rear
visibility, only approximately 70 percent of vehicles had these
technologies during the time they were part of NCAP. Thus, while NCAP
serves a vital safety purpose, only regulation can ensure that all
vehicles are equipped with AEB that meet minimum performance
requirements.
These considerations are of even greater weight when deciding
whether to require a system that can reduce pedestrian crashes, and the
agency has concluded that PAEB is both achievable and necessary.
Pedestrian fatalities are increasing, and NHTSA's testing reveals that
PAEB systems will be able to significantly reduce these deaths.\15\
Manufacturers' responses to adding lead vehicle AEB and other
technologies to NCAP suggest that it will take several years after PAEB
is introduced to NCAP before the market begins to see significant
numbers of new vehicles that are able to meet a finalized NCAP test.
Even so, since PAEB addresses the safety of someone other than a
vehicle occupant, it is not clear if past experience with NCAP is
necessarily indicative of how quickly PAEB systems will reach the
market penetration levels of lead vehicle AEB.
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\15\ NHTSA's accompanying Final Regulatory Impact Analysis
(FRIA) estimates the impacts of this final rule. The FRIA can be
found in the docket for this final rule. The docket number is listed
in the heading of this document.
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A final factor weighing in favor of requiring AEB is that the
technology is significantly more mature now than it was at the time of
the voluntary commitment and when it was introduced into NCAP. NHTSA's
most recent testing has shown that higher performance levels than those
in the voluntary commitment or the existing NCAP requirements are now
practicable. Many model year 2019 and 2020 vehicles were able to
repeatedly avoid impacting the lead vehicle in CIB tests and the
pedestrian test mannequin in PAEB tests, even at higher test speeds
than those prescribed currently in the agency's CIB and PAEB test
procedures.
These results show that AEB systems can reduce the frequency and
severity of both lead vehicle and pedestrian crashes. Mandating AEB
systems would address a clear and, in the case of pedestrian deaths,
growing safety problem. To wait for market-driven adoption, even to the
extent spurred on by NCAP, would lead to deaths and injuries that could
be avoided if the technology were required.

Summary of the NPRM

In view of the significant safety problem and NHTSA's recent test
results, and consistent with the Safety Act and BIL, on June 13, 2023
(88 FR 38632) NHTSA published an NPRM proposing a new FMVSS requiring
AEB systems that can address both lead vehicle and pedestrian
collisions on all new light vehicles. The proposed lead vehicle AEB
test procedures built on the existing FCW, CIB, and DBS NCAP
procedures, but proposed higher speed performance requirements. Crash
avoidance was proposed at speeds up to 100 km/h (62 mph) when manual
braking is applied and up to 80 km/h (50 mph) when no manual braking is
applied during the test. NHTSA proposed testing under both daylight and
darkness lighting conditions, noting the importance of darkness testing
of PAEB because more than three-fourths of all pedestrian fatalities
occur in conditions other than daylight.
The proposal included four requirements for the AEB system for both
lead vehicles and pedestrians. The AEB system would be required to: (1)
provide an FCW at any forward speed greater than 10 km/h (6.2 mph),
presented via auditory and visual modalities, with permissible
additional warning modes, such as haptic; (2) apply the brakes
automatically at any forward speed greater than 10 km/h (6.2 mph) when
a collision with a lead vehicle or a pedestrian is imminent, including
at speeds above those tested by NHTSA; (3) prevent the vehicle from
colliding with the lead vehicle or pedestrian test mannequin when
tested according to the proposed test procedures, which would include
pedestrian tests in both daylight and darkness and two false positive
tests; and (4) provide visual notification to the driver of any
malfunction that causes the AEB system not to meet the minimum proposed
performance requirements.
To ensure test repeatability, NHTSA proposed specifications for the
test devices that would be used in both the lead vehicle and pedestrian
compliance tests, relying in large part on relevant International
Organization for Standardization standards.

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NHTSA proposed that all vehicles manufactured four years after the
publication date of a final rule would be required to meet all
requirements. NHTSA also proposed that all vehicles manufactured on or
after three years after the publication date of a final rule would be
required to meet all requirements except that lower speed PAEB
performance test requirements would not apply. Small-volume
manufacturers, final-stage manufacturers, and alterers would be
provided an additional year (added to those above) to meet the
requirements of the final rule.
NHTSA sought comments on all aspects of the NPRM and any
alternative requirements that would address the safety problem. In
response, over 1,000 comments were received from a wide variety of
stakeholders and interested persons. These comments are available in
the docket for the NPRM.\16\
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\16\ https://www.regulations.gov/docket/NHTSA-2023-0021/comments.
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This Final Rule

After careful consideration of all comments, this final rule adopts
most of the proposed NPRM requirements, with a few of the changes
relevant to significant matters. The differences between the NPRM and
the final rule are noted at the end of this Executive Summary and
discussed in the relevant sections of this preamble.
With this final rule, NHTSA has issued a Final Regulatory Impact
Analysis (FRIA), available in the docket for this final rule (NHTSA-
2023-0021).
NHTSA estimates that systems can achieve the requirements of this
final rule primarily through upgraded software, with a limited number
of vehicles needing additional hardware. Therefore, the incremental
cost associated with this rule reflects the cost of a software upgrade
that will allow current systems to achieve lead vehicle AEB and PAEB
functionality that meets the requirements specified in this rule and
the cost to equip a second sensor (radar) on five percent of the
estimated fleet that is not projected to have the needed hardware.
Taking into account both software and hardware costs, the total annual
cost associated with this final rule is approximately $354 million in
2020 dollars.
Table 1 below summarizes the finding of the benefit-cost analysis.
The projected benefits of this rule greatly exceed the projected costs.
The lifetime monetized net benefit of this rule is projected to be
between $5.82 and $7.26 billion with a cost per equivalent life saved
of between $550,000 and $680,000, which is far below the Department's
recommended value of a statistical life saved, of as $11.6 million in
2020 dollars.
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Differences Between This Final Rule and the NPRM

NHTSA has made a number of changes to the NPRM based on information
from the comments. The changes are discussed below. NHTSA discusses
each of these changes in the relevant sections of this preamble.
In the NPRM, NHTSA estimated that systems can achieve the
proposed requirements through upgraded software alone. Commenters
suggested that in some instances additional hardware will also be
needed, so the incremental cost associated with this rule now includes
the cost of a software upgrade and the cost to equip a second sensor
(radar) on the five percent of the estimated fleet that does not now
have the needed hardware.
NHTSA has made changes to lead time and compliance date
requirements. The NPRM proposed that all vehicles comply with the
requirements within 3 years, except for some higher speed PAEB
performance requirements in darkness (which had 1 year more to comply
than other requirements). This final rule requires that manufacturers
comply with all provisions of the rule at the end of a 5-year period
starting the first September 1 following publication of this rule,
which would be September 1, 2029.\17\ The requirements of this final
rule compel robust AEB systems that are practicable, but the agency has
determined that more time is needed for the technology to mature and be
deployed into all vehicles.\18\ We expect that many vehicles will be
equipped with AEB systems that meet the new rule earlier than September
1, 2029, because of redesign schedules, but that manufacturers will be
able to meet the requirement for all new vehicles by the new start
date.
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\17\ As proposed in the NPRM, this final rule provides small-
volume manufacturers, final stage manufacturers, and alterers an
additional year of lead time. As a result of the changes to the
proposed lead time and compliance date requirements, small-volume
manufactures, final stage manufactures, and alterers would be
required to comply with all provisions of the rule starting
September 1, 2030.
\18\ As part of this extension of the lead time, the agency has
removed the graduated approach to the PAEB performance requirements.
The NPRM proposed that most PAEB requirements be met 3 years after a
final rule, with an additional year for the dark lighting condition
requirement. With the 5-year lead time for all requirements, there
is no need for the phasing-in of requirements, so the agency is not
adopting it.
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This final rule modifies the range of forward speeds at
which the AEB must operate. The NPRM required FCW and AEB systems to
operate at any forward speed greater than 10 km/h. This final rule
places an upper bound on the requirement that an AEB system operate of
145 km/h (90.1 mph) for FCW and lead vehicle AEB and 73 km/h (45.4 mph)
for pedestrian AEB. This final rule also clarifies the environmental
conditions under which the AEB system must perform to be the same
environmental conditions specified in the track testing.
This final rule includes an explicit prohibition against
manufacturers installing a control designed for the sole purpose of
deactivation of the AEB system, except where provided below as it
relates to law enforcement. This final rule also allows for controls
that have the ancillary effect of deactivating the AEB system. For
instance, a manufacturer may choose to deactivate AEB if the driver has
activated ``tow mode'' and the manufacturer has determined that AEB
cannot perform safely while towing a trailer.
This final rule modifies the FCW visual signal location
requirement to increase the specified maximum visual angle from 10
degrees to 18 degrees in the vertical direction. This change from the
NPRM provides manufacturers with the flexibility to locate the visual
warning signal within the typical area of the upper half of the
instrument panel and closer to the central field of view of the driver.
While the agency continues to believe that an FCW visual warning signal
presented near the central forward-looking region is ideal, it does not
consider a head-up display to be necessary for the presentation of the
FCW visual signal that is part of a complete AEB system.
The rule contains several additional minor changes as
well. These include the following:

--In the obstructed pedestrian scenario in PAEB performance tests, the
NPRM did not specify the distance between the pedestrian test dummy and
the farthest obstructing vehicle. This final rule corrects this
oversight.
--In the false activation tests, this final rule adjusts the regulatory
text to clarify that testing for false activation is done with and
without manual brake application.
--Some minor parameters and definitions were modified, and various
definitions were added, to clarify details of the lead vehicle and PAEB
test procedures.
--To increase practicability of running the tests, a third manual brake
application controller option, a force only feedback controller, was
added. The force feedback controller is substantially similar to the
hybrid controller with the commanded brake pedal position omitted,
leaving only the commanded brake pedal force application.
--The procedure in Annex C, section C.3 of ISO 19206-2:2018 is specific
for pedestrian targets, but recent testing performed by the agency
indicates that the three-position measurement specified in Annex C,
section C.3 of ISO 19206-3:2021 provides more reduction in multi-path
reflections and offers more accurate radar cross section values. The
agency is incorporating by reference ISO 19206-3:2021.

II. Background

A. The Safety Problem

There were 38,824 fatalities in motor vehicle crashes on U.S.
roadways in 2020 and early estimates put the number of fatalities at
42,795 for 2022.\19\ This is the highest number of fatalities since
2005. While the upward trend in fatalities may be related to increases
in risky driving behaviors during the COVID-19 pandemic,\20\ agency
data show an increase of 3,356 fatalities between 2010 and 2019.\21\
Motor vehicle crashes have also trended upwards since 2010, which
corresponds to an increase in fatalities, injuries, and property
damage.
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\19\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813266, https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813428.
\20\ These behaviors relate to increases in impaired driving,
the non-use of seat belts, and speeding. NHTSA also cited external
studies from telematics providers that suggested increased rates of
cell phone manipulation during driving in the early part of the
pandemic.
\21\ NHTSA's Traffic Safety Facts Annual Report, Table 2,
https://cdan.nhtsa.gov/tsftables/tsfar.htm#Accessed March 28, 2023.

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[[Page 39691]]

Overall Rear-End Crash Problem
NHTSA uses data from the Fatality Analysis Reporting System (FARS)
and the Crash Report Sampling System (CRSS) to account for and
understand motor vehicle crashes. As defined in a NHTSA technical
manual relating to data entry for FARS and CRSS, rear-end crashes are
incidents where the first event is defined as the frontal area of one
vehicle striking a vehicle ahead in the same travel lane. In a rear-end
crash, as instructed by the 2020 FARS/CRSS Coding and Validation
Manual, the vehicle ahead is categorized as intending to head either
straight, left or right, and is either stopped, travelling at a lower
speed, or decelerating.\22\
---------------------------------------------------------------------------

\22\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813251 Category II Configuration D. Rear-End.
---------------------------------------------------------------------------

In 2019, rear-end crashes accounted for 32.5 percent of all
crashes, making them the most prevalent type of crash.\23\ Fatal rear-
end crashes increased from 1,692 in 2010 to 2,363 in 2019 and accounted
for 7.1 percent of all fatal crashes in 2019, up from 5.6 percent in
2010. Because data from 2020 and 2021 may not be representative of the
general safety problem due to the COVID-19 pandemic, and data from 2022
are not yet available, the following discussion refers to data from
2010 to 2020 when discussing rear-end crash safety problem trends, and
2019 data when discussing specific characteristics of the rear-end
crash safety problem. While injury and property-damage-only rear-end
crashes from 2010 (476,000 and 1,267,000, respectively) and 2019
(595,000 and 1,597,000, respectively) are not directly comparable due
to differences in database structure and sampling, the data indicate
that these numbers have not significantly changed from 2010-2015 (NASS-
GES sampling) and 2016-2019 (CRSS sampling).
---------------------------------------------------------------------------

\23\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141 Traffic Safety Facts 2019, Table 29.
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BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TR09MY24.004

The table below presents a breakdown of all the crashes in 2019 by
the first harmful event where rear-end crashes represent 7.1 percent of
the fatal crashes, 31.1 percent of injury crashes and 33.2 percent (or
the largest percent) of property-damage-only crashes.
---------------------------------------------------------------------------

\24\ Compiled from NHTSA's Traffic Safety Facts Annual Report,
Table 29 from 2010 to 2020, https://cdan.nhtsa.gov/tsftables/tsfar.htm#Accessed March 28, 2023.

---------------------------------------------------------------------------

[[Page 39692]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.005

The following paragraphs provide a breakdown of rear-end crashes by
vehicle type, posted speed limit, light conditions and atmospheric
conditions for the year 2019 based on NHTSA's FARS, CRSS, and the 2019
Traffic Safety Facts sheets.
---------------------------------------------------------------------------

\25\ NHTSA's Traffic Safety Facts Annual Report, Table 29 for
2019, https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141 Accessed March 29, 2024.
---------------------------------------------------------------------------

Rear-End Crashes by Vehicle Type
In 2019, passenger cars and light trucks were involved in the vast
majority of rear-end crashes. NHTSA's ``Manual on Classification of
Motor Vehicle Traffic Accidents'' provides a standardized method for
crash reporting. It defines passenger cars as ``motor vehicles used
primarily for carrying passengers, including convertibles, sedans, and
station wagons,'' and light trucks as ``trucks of 10,000 pounds gross
vehicle weight rating or less, including pickups, vans, truck-based
station wagons, and utility vehicles.'' \26\ The 2019 data show that
crashes where a passenger car or light truck is a striking vehicle
represent at least 70 percent of fatal rear-end crashes, 95 percent of
crashes resulting in injury, and 96 percent of damage only.\27\
---------------------------------------------------------------------------

\26\ https://www-fars.nhtsa.dot.gov/help/terms.aspx.
\27\ NHTSA's Traffic Safety Facts Annual Report, 2019, https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141.

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[[Page 39693]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.006

Rear-End Crashes by Posted Speed Limit
---------------------------------------------------------------------------

\28\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).
---------------------------------------------------------------------------

When looking at posted speed limit and rear-end crashes, data show
that the majority of the crashes happened in areas where the posted
speed limit was 60 mph (97 km/h) or less. The table below shows the
rear-end crash data by posted speed limit and vehicle type from 2019.
About 60 percent of fatal crashes were on roads with a speed limit of
60 mph (97 km/h) or lower. That number is 73 percent for injury crashes
and 78 percent for property-damage-only crashes.
[GRAPHIC] [TIFF OMITTED] TR09MY24.007

Rear-End Crashes by Light Condition
---------------------------------------------------------------------------

\29\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).
\30\ Total percentages may not equal the sum of individual
components due to independent rounding throughout the Safety Problem
section.
---------------------------------------------------------------------------

Slightly more fatal rear-end crashes (51 percent) occurred during
daylight than during dark-lighted and dark-not-lighted conditions
combined (43 percent) in 2019. Injury and property- damage-only rear-
end crashes were reported to have happened overwhelmingly during
daylight, at 76 percent for injury rear-end crashes and 80 percent for
property-damage-only rear-end crashes. The table below presents a
summary of all 2019 rear-end crashes of light vehicles by light
conditions, where the impact location is the front of a light vehicle.

[[Page 39694]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.008

Rear-End Crashes by Atmospheric Conditions
---------------------------------------------------------------------------

\31\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).
---------------------------------------------------------------------------

In 2019, the majority of rear-end crashes of light vehicles were
reported to occur during clear skies with no adverse atmospheric
conditions. These conditions were present for 72 percent of all fatal
rear-end crashes, while 14 percent of fatal rear-end crashes were
reported to occur during cloudy conditions. Similar trends are reported
for injury and property-damage-only crashes. A summary of 2019 rear-end
crashes of light vehicle with frontal impact by atmospheric conditions
is presented in the table below.
---------------------------------------------------------------------------

\32\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).
[GRAPHIC] [TIFF OMITTED] TR09MY24.009

Pedestrian Fatalities and Injuries
While the number of fatalities from motor vehicle traffic crashes
is increasing, pedestrian fatalities are increasing at a greater rate
than the general trend and becoming a larger percentage of total
fatalities. In 2010, there were 4,302 pedestrian fatalities (13 percent
of all fatalities), which increased to 6,272 (17 percent of all
fatalities) in 2019. The latest agency estimation data indicate that
there were 7,345 pedestrian fatalities in 2022.\33\ Since data from
2020 and 2021 may not be representative of the general safety problem
due to the COVID-19 pandemic and data for 2022 are early estimates, the
following sections refer to data from 2010 to 2020 when discussing
pedestrian safety problem trends, and 2019 data when discussing
specific characteristics of the pedestrian safety problem. While the
number of pedestrian fatalities is increasing, the number of
pedestrians injured in crashes from 2010 to 2020 has not changed
significantly, with exception of the 2020 pandemic year. As shown in
the table below, the number and percentage of pedestrian fatalities and
injuries for the 2010 to 2020 period is presented in relationship to
the total number of fatalities and total number of people injured in
all crashes.
---------------------------------------------------------------------------

\33\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813448.

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[[Page 39695]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.010

The following sections present a breakdown of pedestrian fatalities
and injuries by initial impact point, vehicle type, posted speed limit,
lighting condition, and pedestrian age for the year 2019.
---------------------------------------------------------------------------

\34\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079 Pedestrian Traffic Facts 2019 Data, May 2021,
https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813310
Pedestrian Traffic Facts 2020, Data May 2022.
---------------------------------------------------------------------------

Pedestrian Fatalities and Injuries by Initial Point of Impact and
Vehicle Type
In 2019, the majority of pedestrian fatalities, 4,638 (74 percent
of all pedestrian fatalities), and injuries, 52,886 (70 percent of all
pedestrian injuries), were in crashes where the initial point of impact
on the vehicle was the front. When the crashes are broken down by
vehicle body type, the majority of pedestrian fatalities and injuries
occur where the initial point of impact was the front of a light
vehicle (4,069 pedestrian fatalities and 50,831 pedestrian injuries)
(see the table below).\35\
---------------------------------------------------------------------------

\35\ As described previously, passenger cars and light trucks
are the representative population for vehicles with a gross vehicle
weight rating (GVWR) of 4,536 kg (10,000 lbs.) or less.
[GRAPHIC] [TIFF OMITTED] TR09MY24.011

Pedestrian Fatalities and Injuries by Posted Speed Limit Involving
Light Vehicles
---------------------------------------------------------------------------

\36\ NHTSA's Traffic Safety Facts Annual Report, Table 99 for
2019, https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141 Accessed March 29, 2024.
---------------------------------------------------------------------------

In 2019, the majority of pedestrian fatalities from crashes
involving light vehicles with the initial point of impact as the front
occurred on roads where the posted speed limit was 45 mph or less,
(about 70 percent). There is a near even split between the number of
pedestrian fatalities in 40 mph and lower speed zones and in 45 mph and
above speed zones (50 percent and 47 percent respectively with the
remaining unknown or not reported). As for pedestrian injuries, in 34
percent of the sampled data, the posted speed limit is either not
reported or unknown. In

[[Page 39696]]

2019, 57 percent of the pedestrians were injured when the posted speed
limit was 40 mph or below, and 9 percent when the posted speed limit
was above 40 mph with the remaining not reported, reported as unknown,
or reported as no speed limit. The table below shows the number of
pedestrian fatalities and injuries for each posted speed limit.
[GRAPHIC] [TIFF OMITTED] TR09MY24.012

Pedestrian Fatalities and Injuries by Lighting Condition Involving
Light Vehicles
---------------------------------------------------------------------------

\37\ The accompanying FRIA estimates the impacts of the rule
based on the estimated travel speed of the striking vehicle. This
table presents the speed limit of the roads on which pedestrian
crashes occur.
---------------------------------------------------------------------------

The majority of pedestrian fatalities where the front of a light
vehicle strikes a pedestrian occurred in dark lighting conditions,
3,131 (75 percent). There were 20,645 pedestrian injuries (40 percent)
in dark lighting conditions and 27,603 pedestrian injuries (54 percent)
in daylight conditions.

[[Page 39697]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.013

Pedestrian Fatalities and Injuries by Age Involving Light Vehicles
---------------------------------------------------------------------------

\38\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).
---------------------------------------------------------------------------

In 2019, 646 fatalities and approximately 106,600 injuries involved
children aged 9 and below. Of these, 68 fatalities and approximately
2,700 injuries involved pedestrians aged 9 and below in crashes with
the front of a light vehicle. As shown in the table below, the first
two age groups (under age 5 and ages 5 to 9) each represent less than 1
percent of the total pedestrian fatalities in crashes with the front of
a light vehicle. These age groups also represent about 1.5 and 3.8
percent of the total pedestrian injuries in crashes with the front of a
light vehicle, respectively. In contrast, age groups between age 25 and
69 each represent approximately 7 percent of the total pedestrian
fatalities in crashes with the front of a light vehicle, with the 55 to
59 age group having the highest percentage at 10.9 percent. Pedestrian
injury percentages were less consistent, but distributed similarly, to
pedestrian fatalities, with lower percentages reflected in children
aged 9 and below and adults over age 70.

[[Page 39698]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.014

BILLING CODE 4910-59-C

B. Bipartisan Infrastructure Law (BIL)
---------------------------------------------------------------------------

\39\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).
\40\ https://www.census.gov/data/tables/2019/demo/age-and-sex/2019-age-sex-composition.html, Table 12.
---------------------------------------------------------------------------

This final rule responds to Congress's directive that NHTSA require
AEB on all passenger vehicles. On November 15, 2021, the President
signed the Bipartisan Infrastructure Law, codified as the
Infrastructure Investment and Jobs Act (Pub. L. 117-58). Section
24208(a) of BIL added 49 U.S.C. 30129, directing the Secretary of
Transportation to promulgate a rule to establish minimum performance
standards with respect to crash avoidance technology and to require
that all passenger motor vehicles manufactured for sale in the United
States be equipped with a forward collision warning (FCW) system and an
automatic emergency braking system. The FCW and AEB system is required
to alert the driver if the vehicle is closing its distance too quickly
to a vehicle ahead or to an object in the path of travel ahead and a
collision is imminent, and to automatically apply

[[Page 39699]]

the brakes if the driver fails to do so. This final rule responds to
this mandate and is estimated to reduce the frequency and severity of
vehicle-to-vehicle rear-end crashes and to reduce the frequency and
severity of vehicle crashes into pedestrians.
BIL requires that ``all passenger motor vehicles'' manufactured for
sale in the United States be equipped with AEB and FCW. The BIL term
``passenger motor vehicle'' encompasses more vehicle categories than
the term ``passenger car'' that NHTSA defines in 49 CFR 571.3. Thus,
including multipurpose passenger vehicles, trucks, and buses aligns
with Congress's mandate. Additionally, NHTSA considers passenger cars,
truck, buses, and multipurpose passenger vehicles as light vehicles and
generally uses the 10,000 GVWR cut-off for FMVSS that apply to light
vehicles.\41\ As a result, in this final rule, NHTSA requires AEB and
FCW on all passenger cars and multipurpose passenger vehicles, trucks,
and buses with a gross vehicle weight rating (GVWR) of 10,000 lbs. or
less.
---------------------------------------------------------------------------

\41\ See, for example, 49 CFR 571.138, 571.208, and 571.111.
---------------------------------------------------------------------------

BIL further requires that an FCW system alert the driver if there
is a ``vehicle ahead or an object in the path of travel'' if a
collision is imminent.
NHTSA interprets BIL as requiring AEB capable of detecting and
responding to vehicles and objects and authorizing NHTSA to promulgate
specific performance requirements. NHTSA's rule requires light vehicles
to be equipped with FCW and automatic emergency braking (AEB), and the
proposal defines AEB as a system that detects an imminent collision
with vehicles, objects, and road users,\42\ in or near the path of a
vehicle and automatically controls the vehicle's service brakes to
avoid or mitigate the collision.
---------------------------------------------------------------------------

\42\ While AEB is defined as a system that detects imminent
collision with vehicles, objects, and road users, the performance
requirements focus on protecting pedestrians until NHTSA can develop
additional research to support a proposal to expand the performance
requirements.
---------------------------------------------------------------------------

As discussed in the NPRM, section 24208 of BIL does not limit
NHTSA's broad authority to issue motor vehicle safety regulations under
the Safety Act. NHTSA interprets BIL as a mandate to act on a
particular vehicle safety issue and as complementary to NHTSA's
authority under the Safety Act. Thus, pursuant to its authority under
49 U.S.C 30111, NHTSA is requiring all light passenger vehicles to be
equipped with PAEB in addition to AEB. NHTSA is ensuring that PAEB is
available on all light passenger vehicles to address a significant
safety problem, and in so doing, recognizes the availability of
technology capable of preventing needless injuries and lost lives.

C. High-level Summary of Comments on the NPRM

NHTSA received more than a thousand comments on the proposed rule.
The agency received comments from a wide variety of commenters
including advocacy groups, manufacturers, trade associations,
suppliers, and individuals. The advocacy groups submitting comments
included AAA Inc. (AAA), AARP, Advocates for Highway and Auto Safety
(Advocates), America Walks, American Foundation for the Blind (AFB),
Association of Pedestrian and Bicycle Professionals (APBP), Center for
Auto Safety (CAS), Consumer Reports, DRIVE SMART Virginia, Insurance
Institute for Highway Safety (IIHS), International Association of Fire
Chiefs, Intelligent Transportation Society of America (ITS America),
League of American Bicyclists (League), McHenry County Bicycle
Advocates, National Safety Council (NSC), Paralyzed Veterans of America
(PVA), United Spinal Association, Utah Public Lands Alliance, and
Vulnerable Road Users Safety Consortium (VRUSC). Trade associations
submitting comments included Alliance for Automotive Innovation
(Alliance), American Chemistry Council, American Motorcyclist
Association (AMA), Automotive Safety Council (ASC), Autonomous Vehicle
Industry Association (AVIA), the Governors Highway Safety Association
(GHSA), Lidar Coalition, the Motor and Equipment Manufacturers
Association (MEMA), National Automotive Dealers Association (NADA),
National Association of City Transportation Officials (NACTO),
Association for the Work Truck Industry (NTEA), SAE International
(SAE), and Specialty Equipment Market Association (SEMA). We also
received comments from individual vehicle manufacturers such as FCA US
LLC (FCA), Ford Motor Company (Ford), General Motors LLC (GM), American
Honda Motor, Co., Inc. (Honda), Hyundai Motor Company (Hyundai),
Mitsubishi Motors R & D of America, Inc. (Mitsubishi), Nissan North
America, Inc. (Nissan), Porsche Cars North America (Porsche), Rivian
Automotive, LLC (Rivian), Toyota Motor North America, Inc. (Toyota),
and Volkswagen Group of America (Volkswagen). Suppliers and developers
commenting on the NPRM included Adasky North America (Adasky), Applied
Intuition (Applied), Aptiv, Automotive Electronics Products COMPAL
Electronics, Inc. (COMPAL), Autotalks, Forensic Rock, LLC (Forensic
Rock), Humanetics Safety (Humanetics), Hyundai America Technical
Center, Inc. (HATCI), Hyundai MOBIS, imagery Inc. (Imagery), LHP Inc.
(LHP), Luminar Technologies, Inc. (Luminar), Mobileye Vision
Technologies LTD (Mobileye), Owl Autonomous Imaging, Inc. (Owl AI),
Radian Labs LLC (Radian), Robert Bosch LLC (Bosch), Teledyne FLIR
(Teledyne), ZF North America (ZF), and Zoox, Inc. (Zoox). Government
agencies that commented included the National Transportation Safety
Board (NTSB), the City of Houston (Houston), City of Philadelphia
(Philadelphia), Humboldt County Association of Governments, Maryland
Department of Transportation Motor Vehicle Administration (MDOT),
Multnomah County, and Nashville Department of Transportation and
Multimodal Infrastructure (Nashville). Healthcare and insurance
companies submitting comments included American Property Casualty
Insurance Association (APCIA), National Association of Mutual Insurance
Companies, and Richmond Ambulance Authority. The agency also received
approximately 970 comments from individual commenters. In general, the
commenters expressed support for the goals of this rulemaking, and many
commenters offered recommendations on the most appropriate way to
achieve those goals.
Many commenters shared their general support for requiring AEB as
standard equipment on passenger vehicles, while others opposed
finalizing the proposed rule for various technical and policy reasons.
In general, safety advocates supported finalizing the rule, while
vehicle manufacturers opposed various aspects of the proposal, even if
they expressed general support for AEB technology. The agency received
comments on many aspects of the rule, including comments on the
application, the performance requirements, the test procedure
conditions and parameters, and the proposed lead time and phase-in
schedule.
Consumer advocacy groups primarily supported the rule, with
concerns regarding manual deactivation and the proposed requirements
regarding PAEB. They urged that any conditions for AEB deactivation be
restricted and have data supporting deactivation and asserted that any
manual deactivation would need to have multiple steps and require the
vehicle to be stationary. Many suggested that the testing speeds be
increased to cover a larger portion of the safety problem. Another
concern raised

[[Page 39700]]

by advocacy groups was the lack of test procedures covering bicyclists
and users of mobility devices and wheelchairs. They recommended that
the agency add more PAEB testing scenarios, noting that there is a
significant safety risk for pedestrians and all vulnerable road users.
In general, advocacy groups supported the full collision avoidance, no-
contact requirement for all proposed AEB tests as a necessity to uphold
the strength of the rule.
While vehicle manufacturers supported the installation of AEB, the
most significant concerns focused on the stringency of the
requirements. The NPRM proposed the AEB system be operational at any
forward speed above 10 km/h (6.2 mph). Several vehicle manufacturers
and the Alliance opposed the open-ended upper bound, stating it was
impracticable or that it would lead to false activations. These
commenters stated that the lack of a defined maximum operational speed
could create implementation ambiguity and difficulty complying with the
rule due to significant development costs. The NPRM further proposed
full collision avoidance with the lead vehicle during AEB testing (a
no-contact performance requirement). The Alliance, and multiple
manufacturers expressing support for the Alliance' comments, stated
that a no-contact performance requirement is not practicable and
increases the potential for unintended consequences such as inducing
unstable vehicle dynamics, removing the driver's authority, increasing
false activations, and creating conditions that limit bringing new
products to market. These commenters asserted that a lack of rigorous
testing by the agency leaves questions as to actual vehicle performance
in the field.
The vehicle manufacturers also commented on the feasibility of
specific performance requirements under the proposed phase-in schedule,
arguing that the agency was mistaken to assume in the NPRM that most
vehicles have the necessary hardware to implement this rule. They
commented that the proposed phase-in schedule may require redesigns to
their systems outside of the normal product development cycle and
contended that such a scenario would significantly increase the costs
and burdens of compliance. The manufacturers requested that the agency
delay the rule by as much as eight years to afford them time to
redesign their systems in conjunction with the normal vehicle redesign
schedule.
Manufacturers and suppliers generally opposed the agency's proposal
to prohibit manual deactivation of the AEB system above 10km/h.
Commenters stated the need for deactivation during various scenarios,
including four-wheel drive operation, towing, off-road use, car washes
and low traction driving. There were multiple suggestions to adopt the
deactivation criteria of the United Nations Economic Commission for
Europe (UNECE) Regulation No. 152, in place of the NPRM proposed
criteria, and to align with UNECE Regulation No. 152 more generally.
Among suppliers and developers, there was not a consensus on the
no-contact requirement. Commenters such as Adasky and Luminar expressed
support for the no-contact requirement, stating that current technology
is capable of this performance. ZF, Aptiv, and Hyundai MOBIS believed
the proposed no-contact requirement was not practicable and suggested
harmonization with UNECE Regulation No. 152. Generally, those opposed
to the no-contact requirement supported hybrid or speed reduction
approaches.\43\
---------------------------------------------------------------------------

\43\ A kind of hybrid approach would maintain no-contact
requirements for lower-mid-range speeds while permitting contact at
higher speed if acceptable speed reductions that reduce the risk of
serious injury can be achieved in the higher-speed scenarios.
---------------------------------------------------------------------------

ZF, HATCI, and Aptiv supported the ability to manually deactivate
the AEB system and recommended harmonization with UNECE Regulation No.
152 deactivation criteria. Imagry opposed the entirety of the NPRM as
drawing resources and development away from fully autonomous driving,
while Autotalks supported the regulation as ``urgently needed.''
Finally, most individual commenters expressed general support to
the goals of this rule, citing the vulnerability of pedestrians on or
near roadways. A significant portion of these commenters also noted
that children, people with dark skin tones, and those using a
wheelchair or mobility device are particularly vulnerable. Individual
commenters opposed to this rule cited concerns about off-road operation
and false activation.

D. Summary of the Notice of Proposed Rulemaking

NHTSA published the NPRM for this final rule on June 2, 2023 (88 FR
38632). Because this final rule adopts almost all of the requirements
proposed in the NPRM, this summary is brief and mirrors the description
of the final rule provided in the Executive Summary, supra.
1. The NPRM proposed creating a new FMVSS to require AEB systems on
light vehicles that can reduce the frequency and severity of both rear-
end and pedestrian crashes. The proposed AEB performance requirements
were intended to ensure that an AEB system is able to automatically and
completely avoid collision with the rear of another vehicle or a
pedestrian in specific combinations of scenarios and speeds, while
continuing to alert and apply the brakes at speeds beyond those in the
test procedure.
2. The NPRM proposed four requirements for the AEB systems. The
proposed AEB system must: (a) provide the driver with a forward
collision warning (FCW) at any forward speed greater than 10 km/h (6.2
mph); (b) automatically apply the brakes at any forward speed greater
than 10 km/h (6.2 mph) when a collision with a lead vehicle or a
pedestrian is imminent; (c) prevent the vehicle from contacting the
lead vehicle (i.e., vehicle test device) or pedestrian test device when
tested according to the proposed test procedures; and (d) detect AEB
system malfunctions and notify the driver of any malfunction that
causes the AEB system not to meet the proposed minimum performance
requirements of the safety standard.
3. The NPRM's test procedures evaluate the lead vehicle AEB
performance, PAEB performance, and two scenarios that evaluate
situations where braking is not warranted (i.e., false positives).
Under this proposed requirement, crash avoidance braking is considered
to have occurred when the automatic portion of the brake activation
(excluding any manual braking) exceeds 0.25g.
4. For the lead vehicle AEB performance, the agency proposed three
test scenarios: lead vehicle stopped, lead vehicle decelerating, and
lead vehicle slower-moving. Each lead vehicle scenario is tested at
specific speeds or within specified ranges of speeds to evaluate the
AEB performance with and without applying manual braking to the subject
vehicle.
For the lead vehicle stopped scenario, the agency proposed that the
subject vehicle must perform when no manual braking is used at speeds
ranging from 10 km/h to 80 km/h, and from 70 km/h to 100 km/h when
manual braking is used. The subject (and lead vehicle) speeds proposed
for the decelerating lead vehicle scenario were 50 km/h and 80 km/h
while the proposed range of lead vehicle deceleration was 0.3 g to 0.5
g. Additionally, for the decelerating lead vehicle scenario, the agency
proposed a headway range of 12 m to 40 m for each of the two subject
vehicle speeds. For the slower-moving lead vehicle scenario, a subject
vehicle must perform at speeds ranging from 40 km/h to 80 km/h when no
manual braking

[[Page 39701]]

is used, while a subject vehicle must perform at speeds ranging from 70
km/h to 100 km/h when manual braking is used.
5. For the assessment of PAEB performance, the proposed test
procedures evaluate the subject vehicle in three pre-crash scenarios
involving pedestrians: (a) where the pedestrian crosses the road in
front of the subject vehicle, (b) where the pedestrian walks alongside
the road in the path of the subject vehicle, and (c) where the
pedestrian stands in the roadway in front of the subject vehicle. The
NPRM proposed a specified range of speeds in both daylight and darkness
lighting conditions with lower and upper beam headlamps activated.
6. NHTSA proposed that AEB systems continuously detect system
malfunctions. If an AEB system detects a malfunction that prevents it
from performing its required safety function, the vehicle would provide
the vehicle operator with a warning. The warning would be required to
remain active as long as the malfunction exists while the vehicle's
starting system is on. NHTSA considers a malfunction to include any
condition in which the AEB system fails to meet the proposed
performance requirements. NHTSA proposed that the driver be warned in
all instances of component or system failures, sensor obstructions,
environmental limitations (like heavy precipitation), or other
situations that would prevent a vehicle from meeting the proposed AEB
performance requirements.
7. With respect to compliance dates, the NPRM proposed that
vehicles manufactured on or after September 1, three years after the
publication date of a final rule, but before September 1, four years
after the publication date of a final rule, would be required to meet
all requirements except that lower speed PAEB performance test
requirements. Vehicles manufactured four years after the publication
date of a final rule would be required to meet all requirements
specified in the final rule. NHTSA proposed that small-volume
manufacturers, final-stage manufacturers, and alterers would be
provided an additional year of lead time for all requirements.

E. Additional Research Conducted in 2023

While past testing conducted in support of the NPRM provided ample
support for the proposed performance requirements, NHTSA conducted
additional research in 2023, which included an evaluation of the newest
vehicles available on the market.\44\ The new research confirmed that
AEB and PAEB performance maintained good performance when compared with
previous testing. This research used three test scenarios to evaluate
the AEB performance of six light vehicles. The vehicles tested included
the 2023 BMW iX, 2023 Ford F-150 Lightning, 2023 Hyundai Ioniq 5
Limited, 2024 Mazda CX-90 Turbo S, 2023 Nissan Pathfinder SL, and the
2023 Toyota Corolla Hybrid XLE. The lead vehicle testing evaluated the
effects of regenerative braking settings for electric (and some hybrid)
vehicles, adaptive cruise control settings, and ambient lighting
conditions on the AEB performance of these vehicles.
---------------------------------------------------------------------------

\44\ NHTSA's 2023 Light Vehicle Automatic Emergency Braking
Research Test Summary and NHTSA's 2023 Light Vehicle Pedestrian
Automatic Emergency Braking Research Test Summary, available in the
docket for this final rule (NHTSA-2023-0021).
---------------------------------------------------------------------------

The lead vehicle scenarios used in this research included the
proposed conditions of lead vehicle stopped, moving, and decelerating.
All conditions and parameters for this research were consistent with
those described in the proposed rule. For nominal testing (tests not
designed to investigate a particular condition or parameter) the Toyota
used in this research avoided contacting the vehicle test device at all
speeds tested from 10 km/h to 80 km/h (50 mph) in the lead vehicle
stopped condition. The Mazda avoided contacting the lead vehicle test
device in all lead vehicle stopped conditions up to 60 km/h (37.5 mph).
BILLING CODE 4910-59-P

[[Page 39702]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.015

[[Page 39703]]

The Toyota, BMW, and Hyundai avoided contacting the lead vehicle
test device in the lead vehicle moving scenarios for all speeds tested.
The Mazda contacted the test device in a single trial at 80 km/h (50
mph) while avoiding contact in all other tested conditions including 4
other trials conducted at 80 km/h.
---------------------------------------------------------------------------

\45\ SV is short for ``subject vehicle.''
\46\ POV is short for ``principal other vehicle.''
[GRAPHIC] [TIFF OMITTED] TR09MY24.016

For the lead vehicle decelerating scenario, the BMW did not contact
the lead vehicle test device in any tested condition while the Toyota
contacted the test device during three of the five trials performed at
80 km/h. Other vehicles contacted the test device as shown in the table
below.

[[Page 39704]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.017

The agency also studied lead vehicle AEB performance in darkness.
Results from the dark ambient lighting tests are shown in the table
below. The lead vehicle stopped scenario was used for all day/darkness
comparative tests. The results observed during the dark ambient tests
were largely consistent with those produced during the daylight tests.
The dark versus day contact results observed for a given test speed
were identical or nearly identical for the Hyundai, Mazda, Nissan, and
Toyota. Where impacts occurred, the impact speeds were very close.

[[Page 39705]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.018

The agency also studied the effects of regenerative braking
settings for electric and hybrid electric vehicles on the performance
of lead vehicle AEB. Again, the lead vehicle stopped test scenario was
used for this comparison. The

[[Page 39706]]

regenerative braking settings did not have a negative effect on the
performance of the tested AEB systems. As expected, performance under
the highest regenerative braking settings was slightly better that the
lower, or off, settings. However, the effect of regenerative brake
setting on the vehicle's ability to avoid contact with the lead vehicle
test device was dependent on the vehicle tested.
[GRAPHIC] [TIFF OMITTED] TR09MY24.019

[[Page 39707]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.020

The agency also conducted additional PAEB testing. The same
vehicles used for the lead vehicle testing presented above were used to
evaluate their PAEB performance consistent with the proposed rule. The
results of this testing

[[Page 39708]]

are summarized in the table below. The table provides the maximum speed
tested at which the vehicle avoided contacting the pedestrian test
device. Of specific note, one vehicle avoided contacting the pedestrian
test device at all speeds tested. Some vehicles contacted the test
device at 10 km/h but under further testing, demonstrated the ability
to avoid contacting the pedestrian test device at much higher speeds.
Further details of this testing and additional results are available in
the report contained in the docket provided at the beginning of this
final rule.
[GRAPHIC] [TIFF OMITTED] TR09MY24.021

BILLING CODE 4910-59-C

III. Final Rule and Response to Comments

A. Summary of the Final Rule (and Modifications to the NPRM)

With a few notable exceptions, this final rule adopts the
performance requirements from the proposed rule. This rule requires
manufacturers to install AEB systems that meet specific performance
requirements. These performance requirements include the installation
of an AEB system, track testing requirements for avoiding both lead
vehicles and pedestrians, false activations test requirements, and
malfunction indication requirements.
This final rule includes four requirements for AEB systems for both
lead vehicles and pedestrians. First, there is an equipment requirement
that vehicles have an AEB system that provides the driver with an FCW
at any forward speed greater than 10 km/h (6.2 mph) and less than 145
km/h (90.1 mph). The FCW must be presented via auditory and visual
modalities when a collision with a lead vehicle or a pedestrian is
imminent. This final rule includes specifications for the auditory and
visual warning components consistent with those of the proposed rule,
with some modifications to keep the effectiveness of the FCW while
reducing the potential costs associated with this rule for some vehicle
designs. Similarly, this final rule includes an equipment requirement
that light vehicles have an AEB system that applies the brakes
automatically at any forward speed that is greater than 10 km/h (6.2
mph) and less than 145 km/h (90.1 mph) when a collision with a lead
vehicle is imminent, and at any forward speed greater than 10 km/h (6.2
mph) and less than 73 km/h (45.4 mph) when a collision with a
pedestrian is

[[Page 39709]]

imminent. The maximum speed of lead vehicle AEB is modified from the
NPRM, which did not include upper limits on speeds. NHTSA also
clarified that this requirement applies only when environmental
conditions permit.
Second, the AEB system is required to prevent the vehicle from
colliding with the lead vehicle or pedestrian test devices when tested
according to the standard's test procedures. These track test
procedures have defined parameters, including travel speeds up to 100
km/h (62.2 mph), that ensure that AEB systems prevent crashes in a
controlled testing environment. The three scenarios for testing
vehicles with a lead vehicle and four scenarios for testing vehicles
with a pedestrian test device are finalized as proposed. The agency has
finalized pedestrian tests in both daylight and darkness, while testing
using the lead vehicle test device is conducted in daylight only as
proposed.
Third, this final rule includes the two false activation tests,
driving over a steel trench plate and driving between two parked
vehicles, in which the vehicle is not permitted to brake in excess of
specified amounts proposed in the NPRM.
Finally, a vehicle must detect AEB system malfunctions and notify
the driver of any malfunction that causes the AEB system not to meet
the minimum proposed performance requirements. The system must
continuously detect system malfunctions, including performance
degradation caused solely by sensor obstructions. If the system detects
a malfunction, or if the system adjusts its performance such that it
will not meet the requirements of the finalized standard, the system
must provide the vehicle operator with a telltale notification. This
final rule has also clarified that the purpose of the malfunction
telltale is to provide information about the operational state of the
vehicle. Some commenters understood the NPRM to have required that the
malfunction telltale activate based on information about the vehicle's
surroundings such as low friction road surfaces.
This final rule includes several changes to the NPRM based on the
comments received:
First, NHTSA includes in this final rule an explicit prohibition
against manufacturers installing a control designed for the sole
purpose of deactivating the AEB system but allows for controls that
have the ancillary effect of deactivating the AEB system (such as
deactivating AEB if the driver has activated ``tow mode'' and the
manufacturer has determined that AEB cannot perform safely while
towing).
NHTSA also modifies the FCW visual signal location requirement in
this final rule to increase the specified visual angle from 10 degrees
to 18 degrees in the vertical direction. This change from the NPRM
provides manufacturers with the flexibility to locate the visual
warning signal within the typical area of the upper half of the
instrument panel and closer to the central field of view of the driver.
While the agency continues to believe that an FCW visual warning signal
presented near the central forward-looking region is ideal, it does not
consider a head-up display to be necessary for the presentation of the
FCW visual signal.
In addition, NHTSA modifies in this final rule the range of forward
speeds at which the AEB must operate. The NPRM required FCW and AEB
systems to operate at any forward speed greater than 10 km/h. This
final rule places an upper bound on the requirement that an AEB system
operate of 145 km/h (90.1 mph) for FCW and lead vehicle AEB and 73 km/h
(45.4 mph) for pedestrian AEB. This final rule also clarifies the
environmental conditions under which the AEB system must perform to be
the same environmental conditions specified in the track testing.
NHTSA also makes a minor adjustment in this final rule to the
measurement method used to characterize the radar cross-section for the
pedestrian test devices. It maintains the cross-section boundaries
contained within the proposed rule as incorporated from ISO 19206-
2:2018 but uses parts of the updated measurement method incorporated
from ISO 10206-3:2021. This newer method was proposed for use in
measuring the vehicle test device, while the older measurement method
was proposed for the pedestrian test devices. The newer method provides
for better filtration of noise by using average measurements taken at
three radar heights as opposed to the single measurement height
specified in the older method. This final rule modifies the measurement
methods for the pedestrian test device to match the method used when
characterizing the vehicle test device.
Finally, this final rule makes a few significant changes to the
lead-time and phase-in requirements. Instead of the deadline proposed
under the NPRM, this final rule requires that manufacturers comply with
all provisions of the rule at the end of the 5-year period starting the
first September 1 after this publication. This will provide
manufacturers with more time to meet the requirements of this final
rule, as most vehicles do not currently meet all of the performance
requirements set forth in this final rule and in light of manufacturer
redesign schedules. The added lead time avoids significantly increasing
the costs of the rule by compelling equipment redesigns outside of the
normal production cycle.
As part of this extension of the lead time, the agency has removed
the phase-in approach to the PAEB performance requirements. While the
NPRM proposed the most stringent PAEB requirements be met 4 years after
a final rule (1 year more than all the other requirements), the agency
is finalizing a 5-year lead time for all requirements (eliminating the
phasing in of requirements during the lead time).

B. Application

NHTSA proposed that the new FMVSS No. 127 apply to all passenger
cars and to all multipurpose passenger vehicles, trucks, and buses with
a GVWR of 4,536 kilograms (10,000 pounds) or less. The agency did not
propose that the new FMVSS apply to vehicles with a GVWR over 4,536
kilograms (10,000 pounds) or to include motorcycles or low-speed
vehicles.
Vehicle Body Types
Several commenters requested that NHTSA consider various vehicle
types in the application of the new FMVSS. The Alliance noted that the
agency's analysis focused only on performance for sedan, SUV and
crossover, and pickup vehicles, and did not consider the constraints
associated with the installation of sensors on vehicles with certain
vehicle designs such as sports cars, which may affect system
capabilities based on unique design characteristics and low profile.
FCA noted that the NPRM did not include the low-speed vehicle (LSV)
class and supported their inclusion in this rule, in part based on the
inclusion of LSVs in the most recent modifications to FMVSS No. 111 and
FMVSS No. 141.
While NHTSA acknowledges the Alliance's concerns that mounting
forward-looking sensors on certain vehicle body types, such as sports
cars, may present some challenges, we believe that technology already
present on some existing production vehicles can be adapted to address
the concern. We also believe that 5 years provides adequate lead time
for manufacturers to consider the changes necessary to their models to
implement AEB. We further note that manufacturers are not restricted as
to sensor placement. Existing production vehicles have sensors located
in a variety of places. NHTSA is aware of several vehicles

[[Page 39710]]

equipped with radar and camera sensors mounted in the cabin near the
rearview mirror. Such a sensor configuration would avoid the
installation constraints imposed by small bumpers, avoid placement
behind carbon fiber material, and accommodate placement further above
the ground.
Regarding FCA's comment, LSVs were excluded from the scope of the
final rule for several reasons. First, there are no LSVs on the market
that NHTSA is aware of that are currently equipped with AEB or PAEB.
This means that NHTSA was not able to procure a vehicle for testing or
otherwise evaluate how a LSV would perform if equipped with AEB/PAEB.
Second, there is a lack of specific safety data to support an argument
that LSVs should be equipped with AEB/PAEB. NHTSA does not want to
preclude such vehicles from being equipped with these safety systems,
but the current safety data does not provide justification for
including them in this rule. Finally, and as discussed in the FRIA,
LSVs were not included due to uncertainty about the feasibility and
practicability of AEB for those vehicles. Although LSVs were included
in the two most recent standard of significance (FMVSS 111 Backup
Camera and FMVSS 141 Sound for Electric Vehicles) without
practicability concerns, we note that those standards include
requirements that provide aids to assist the driver or alerts the
driver. In such cases, those features do not require the vehicle to
react but instead elicit a driver reaction. As these vehicles were not
included in the testing conducted by the agency, our analysis is unable
to characterize the performance of AEB on these vehicles. Therefore, in
the absence of any data to characterize how these systems may perform
on LSVs, they were not included in the final rule.
Heavier Vehicles
The Alliance and FCA commented about the interaction between the
proposed standard and FMVSS Nos. 105 and 135, which regulate braking.
The Alliance recommended a comprehensive review of the impact of the
proposed rule with appropriate accommodations to exclude or include a
cap on the applicability of the proposal based on vehicle weight. The
Alliance stated that typical electronic stability control (ESC) systems
may not provide the fluid flow rates needed to produce the braking
performance necessary to meet the proposed rule. FCA noted that the
proposed standard applies to vehicles between 7,716 pounds GVWR (the
upper limit for FMVSS No. 135 application) and 10,000 pounds GVWR,
opining that this proposed standard is not intended to force changes in
the underlying braking performance of vehicles in that range and noting
that testing has not been conducted on vehicles over 7,000 pounds GVWR.
FCA suggested limiting application of proposed FMVSS No. 127 to
vehicles under 7,716 pounds GVWR.
NHTSA evaluated compliance test results for FMVSS No. 135 conducted
over the last several years. There were 30 vehicles included in this
testing, including small sedans, large pickup trucks, minivans, SUVs
and other vehicle types to which this new FMVSS would apply. The
results indicate that the braking performance of nearly all vehicles
was much better than what FMVSS No. 135 requires and the average
deceleration for the larger pickup trucks also outperformed some of the
smaller sedans, SUVs, and minivans. These test results indicate that
braking performance is more than sufficient to permit compliance with
this final rule without a need for braking changes or supplements.
While this rule is not intended to force changes in the underlying
braking performance of vehicles, the commenters stopped short of
asserting that braking improvements would be necessary, stating only
that improvements may be necessary. Moreover, even if underlying
braking performance improvements were necessary, nothing in the
comments suggests that there are any technical barriers or any other
impediments that would make such improvements infeasible.
Automated Driving Systems
Several commenters suggested exempting vehicles with automated
driving systems from the application of some or all of the proposed
FMVSS No. 127. Volkswagen recommended exempting autonomous vehicles
(AVs) from the parts of the regulation that involve displaying warnings
and the parts for which manipulation of manual controls is part of the
test procedure. Similarly, AVIA requested that the forward collision
warning requirements not apply to AVs.
Zoox requested that the proposed FMVSS not apply to AVs. Zoox
viewed the proposed rule as directed toward human drivers, and that
applying it to AVs may result in unintended consequences, such as
establishing emergency collision avoidance standards for AVs without
considering other avoidance tools available to AVs, thereby
constraining their safety capabilities.
AVIA also provided suggested changes to the proposed application
language that would exclude vehicles equipped with ADS from the
requirement to have an AEB system if the ADS meets the performance
requirements of the proposed standard. The Alliance commented that ADS-
equipped vehicles without manual controls should be exempt from the
driver warning and DBS requirements, which it viewed as relevant only
when there is a human driver and similarly that the DBS requirements
should be applicable only if a brake pedal is installed or required to
be installed in the vehicle.
NHTSA expects that ADS-equipped vehicles are capable of meeting the
performance requirements of this rule, especially those related to
identifying crash imminent situations with vehicles and pedestrians and
applying the brakes to avoid contact. Volkswagen is correct that NHTSA
is considering how to address telltales, alerts, and warnings, like
FCW, in the context of vehicles driven by ADS.\47\ While NHTSA
continues to engage in research to support the related rulemakings
evaluating the application of existing FMVSS to ADS-equipped vehicles,
NHTSA is finalizing this rule for all light vehicles and will consider
future modifications regarding telltales, alerts, and warnings, as well
as crash avoidance standards, generally, for ADS-equipped vehicles as
needed under separate rulemaking efforts.\48\
---------------------------------------------------------------------------

\47\ See https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202304&RIN=2127-AM07.
\48\ See https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202304&RIN=2127-AM00.
---------------------------------------------------------------------------

C. Definitions

The proposed rule contained key definitions to facilitate the
understanding of the rule. While there were 15 proposed definitions
included in section S4 of the proposed new FMVSS, this section focuses
on those raised in comments.
AEB System
The NPRM defined an automatic emergency braking system as a system
that detects an imminent collision with vehicles, objects, and road
users in or near the path of a vehicle and automatically controls the
vehicle's service brakes to avoid or mitigate the collision. Several
commenters recommended changes to the definition of AEB system:
Bosch asked NHTSA to consider adopting the definition of ``Advanced
Emergency Braking System (AEBS)'' used in United Nations Regulation No.
152 (UNECE R152) to promote global harmonization and enhance clarity in

[[Page 39711]]

the terminology used across various jurisdictions.
Porsche and Volkswagen stated that the AEB system requirements
throughout the NPRM require performance metrics specific to mitigating
collisions with lead vehicles and pedestrians, generally not mitigating
collisions with objects, but the proposed definition for AEB includes
reference to ``objects'' and ``road users.'' Specifically, Porsche
referred to the requirements that the vehicle is required not to apply
braking when encountering a steel trench plate. Porsche expressed
concern that, by including ``object,'' the AEB definition could
introduce confusion in whether braking could be applied in false
activation tests. Volkswagen noted that the trench plate could be
categorized as an ``object.'' Bosch commented that the broad definition
poses challenges in requiring that there is no collision with any
``object.''
In reference to the term ``road users,'' Porsche and Volkswagen
commented that the NPRM referenced pedestrians and was not more broadly
inclusive of other road-users such as bicyclists. Both recommended
replacing the term ``road user'' with ``pedestrian'' to align with the
proposed requirements. Bosch did not specifically address the term
``road users,'' but recommended that NHTSA replace ``object'' with
``pedestrian'' in the proposal for more clarity and consistency in the
context of the FCW and AEB system.
An anonymous commenter stated that the AEB system definition does
not specify what constitutes a ``crash imminent situation'' or how the
system determines if the driver has not applied the brakes, or how much
braking force is applied to the system. This commenter noted that these
are important details that may affect the performance and effectiveness
of the AEB system.
BIL requires that an FCW system alert the driver if there is a
``vehicle ahead or an object in the path of travel'' if a collision is
imminent. Consistent with this definition, NHTSA defines an AEB system
as one that detects an imminent collision with a vehicle or with an
object. However, nothing in the definition of AEB system requires
vehicles to detect and respond to imminent collisions with all vehicles
or all objects in all scenarios. Such a requirement would be
unreasonable given the wide array of harmless objects that drivers
could encounter on the roadway that do not present safety risks.
The agency has reviewed the various definitions used in the NPRM to
assess whether meaningful harmonization could be achieved with UNECE
regulations. In UNECE Regulation No. 152, ``Advanced Emergency Braking
System (AEBS)'' means a system which can automatically detect an
imminent forward collision and activates the vehicle braking system to
decelerate the vehicle with the purpose of avoiding or mitigating a
collision. The definition proposed in the NPRM is functionally very
similar, but uses language from BIL. Unlike UNECE Regulation No. 152,
NHTSA's definition also provides a level of clarity as to where the
detection of vehicles, objects, and road users must occur, that is ``in
or near the path of a vehicle.''
The commenters' concern that this definition requires detection of
and reaction to ``all objects'' is unfounded. NHTSA has also considered
the use of the term ``road users'' in the AEB definition. NHTSA is
aware of manufacturers that have designed AEB systems to detect
pedestrians. However, the performance requirements make clear that this
final rule requires detection and reaction to pedestrians and lead
vehicles. The use of ``objects'' and ``road users'' merely identify
potential hazards on a road that may require emergency braking, but are
not intended to impose requirements beyond the requirements set forth
in the standard.
The agency considered comments seeking inclusion of various
performance requirements in the definitions section. Those comments did
not explain why such a change is necessary. As a general matter of
regulatory structure, NHTSA limits the definition section to defining
terms; the operative regulatory text is the appropriate location for
performance requirements and other directives of substantive effect.
Therefore, NHTSA adopts the proposed definition of AEB, which is
defined as a system that detects an imminent collision with vehicles,
objects, and road users in or near the path of a vehicle and
automatically controls the vehicle's service brakes to avoid or
mitigate the collision.
Forward Collision Warning
The NPRM defined forward collision warning as an auditory and
visual warning provided to the vehicle operator by the AEB system that
is designed to induce immediate forward crash avoidance response by the
vehicle operator.
Consistent with its comment about alignment of the definition of
AEB with UNECE R152, Bosch recommended that NHTSA adopt UNECE R152's
Collision Warning definition for the FCW definition: ``a warning
emitted by the [Advanced Emergency Brake System] AEBS to the driver
when the AEBS has detected a potential forward collision.''
NHTSA has finalized the definition of FCW as an auditory and visual
warning provided to the vehicle operator by the AEB system that is
designed to induce immediate forward crash avoidance. This definition
provides clarity that both an auditory and visual warning are necessary
for a complete warning that is most likely to reengage a distracted
driver. For purposes of the test procedure established in this final
rule, if only the visual or only the auditory component of the FCW is
provided, then the FCW onset has not happened, and the test procedure
steps will not take place until both the auditor and visual components
are both in place. As such, the UNECE R152 definition suggested by the
commenters does not provide this needed clarity.
Zoox also recommended changes to the FCW definition to clarify
applicability to conventional vehicles with human drivers only. As
noted above, NHTSA is finalizing this rule for all light vehicles and
will consider future modifications regarding telltales, alerts, and
warnings, as well as crash avoidance standards, generally, for ADS-
equipped vehicles as needed under separate rulemaking efforts. Because
NHTSA is not adjusting requirements to accommodate ADS, no definition
changes are required to address this issue.
Onset
Commenters requested clarification or addition to the definitions
to further clarify the proposed requirements and test procedures. The
NPRM defined ``forward collision warning onset'' as the first moment in
time when a forward collision warning is provided. Automotive Safety
Council sought clarification whether this would be measured in terms of
a signal output on the Controller Area Network (CAN) bus, or measured
by sound physically emitted from the speaker. NHTSA clarifies that FCW
onset would be determined via measurement of the FCW auditory signal
sound output within the vehicle cabin and the illumination of the FCW
visual signal. CAN bus information would not be used to assess FCW
onset.
The NPRM did not provide a definition of braking onset. Humanetics
stated that the term ``vehicle braking onset'' needed further
clarification in all test protocols. Humanetics suggested a target
value of speed change or deceleration value should be used as an
indicator of the time of braking onset.

[[Page 39712]]

NHTSA has decided to clarify the term ``vehicle braking onset'' in
the regulation text as Humanetics suggested, by defining the ``subject
vehicle braking onset'' as the point at which the subject vehicle
achieves a deceleration of 0.15g due to the automatic control of the
service brakes. To ensure clarity in the PAEB test procedure, NHTSA has
used the term ``subject vehicle braking onset'' to clarify that NHTSA
is referring to the vehicle braking onset of the subject vehicle. The
0.15g deceleration was adopted based on the agency's experience
conducting AEB testing as this value has proven a reliable marker for
PAEB onset during track testing.\49\
---------------------------------------------------------------------------

\49\ https://www.regulations.gov/document/NHTSA-2021-0002-0002.
---------------------------------------------------------------------------

Other Definitions
NHTSA does not believe that any further additional definitions are
necessary for manufacturers to understand the performance requirements
of the standard or their obligations. NHTSA believes that terms
appearing within the proposed definitions are sufficiently clear from
the context of the regulation. For example, we believe the meaning of
``crash imminent situation'' is discernable from close review of the
performance requirements, including the test procedures; from these,
the commenter can determine what the agency would consider crash
imminent for the set of testable ranges included in this rule.
Finally, NHTSA acknowledges Consumer Reports' and AAA's requests to
limit the use of the terms CIB and DBS. NHTSA has already done this by
excluding those terms from the regulatory text. While NHTSA used CIB
and DBS throughout the preamble to the NPRM and in this final rule, it
is doing so because these terms are frequently used by industry, and
their use in the preamble helps readers understand what NHTSA is
saying, particularly in the context of prior research and NCAP, which
use those terms.

D. FCW and AEB Equipment Requirements

NHTSA proposed that an FCW must provide the driver warning of an
impending collision when the vehicle is traveling at a forward speed
greater than 10 km/h (6.2 mph). Similarly, the NPRM require a vehicle
to have an AEB system that applies the service brakes automatically
when a collision with a lead vehicle or pedestrian is imminent at any
forward speed greater than 10 km/h (6.2 mph). NHTSA stated in the NPRM
that this minimum speed should not be construed to prevent a
manufacturer from designing an AEB system that activates at speeds
below 10 km/h (6.2 mph).
This proposed requirement was described as an equipment requirement
with no associated performance test. No specific speed reduction or
crash avoidance would be required. However, this requirement was
included to ensure that AEB systems are able to function at all times,
including at speeds above those NHTSA proposed as part of the
performance test requirements where on-track testing is currently not
practicable. NHTSA received comments regarding both the minimum
required activation speed and the lack of maximum activation speed.
1. Minimum Activation Speed
Comments
MEMA supported not having FCW and AEB performance requirements at a
speed below 10 km/h (6 mph), opining that AEB systems do not offer
consistent performance at such low speeds.
Bosch and Volkswagen suggested changing the FCW minimum activation
speed to 30 km/h. Bosch believed that FCW may not be beneficial at
lower speeds because the AEB system proves to be a sufficient solution.
Bosch stated that at lower velocities no driver reaction is required
because the AEB intervention can fully avoid the collision after the
``last time to steer'' has already occurred. According to Bosch, as the
vehicle speed increases, from 30 km/h upwards, the last point to steer
gradually moves to a point after the last point to brake. In effect, a
driver warning then becomes beneficial, and FCW can help the driver
take appropriate action to avoid or mitigate a collision.
Volkswagen stated that setting a requirement for FCW at low speeds
can lead to high false positive rates. Volkswagen also noted that
meeting the proposed performance requirements depended on the FCW being
issued before the activation of AEB, and could lead to very sensitive
system behavior, especially for PAEB. Volkswagen suggested increasing
the minimum FCW activation speed to 30 km/h, but suggested it would
still be acceptable to display the FCW symbol simultaneously with AEB
activation at speeds below 30 km/h to make the driver aware of the
event that just occurred.
The Center for Auto Safety disagreed with the 10 km/h minimum speed
threshold saying that it was not clear why it was selected. The Center
for Auto Safety commented that PAEB should be activated as soon as the
vehicle is shifted into gear to avoid injurious or fatal rollovers of
children and other hazards. Consumer Reports commented that it
understood the technical reasons for the proposed minimum speed of 10
km/h (6.2 mph), but expressed concern that such a lower speed bound
would fail to address the issue of what it described as ``frontover''
incidents.\50\ Consumer Reports said there had been an increase in
``frontover'' incidents since 2016, and that it believed that the
increasing market share of larger vehicles with increased blind zones
was correlated with this increase.
---------------------------------------------------------------------------

\50\ There is not yet a finalized definition of ``frontover''
that is used within NHTSA or outside of NHTSA, and NHTSA is
currently researching how this crash type should be defined. As
NHTSA previously indicated, until more data is gathered via the Non-
Traffic Surveillance (NTS) system, actual frontover crash counts are
difficult to confirm due to the challenges law enforcement faces in
distinguishing these crashes from other forward moving vehicle
impacts with non-motorists and to the locations where these crashes
often occur. For example, a forward moving vehicle crash involving a
driver turning into a driveway and striking a child playing in the
driveway would typically not be considered a frontover; but if that
driver struck the child while pulling out of a garage (having backed
into the garage), it would be considered a frontover. These nuances
pose difficulties for law enforcement to accurately capture
frontover incidents which, in turn, complicates our data collection.
Additionally, frontover crashes frequently occur in driveways and
parking lots that are not located on the public trafficway; thus,
law enforcement may not report these occurrences using a crash
report.
---------------------------------------------------------------------------

Agency Response
NHTSA is finalizing a minimum activation speed of 10 km/h as
proposed. The agency considered increasing this minimum to 30 km/h, as
suggested by some commenters, to avoid unwanted and unnecessary alert
at low speeds. However, after considering the potential impacts of such
a modification, particularly the safety of pedestrians, the agency is
finalizing the minimum activation speed as proposed for the forward
collision warning. This 10 km/h minimum threshold is also harmonized
with UNECE Regulation No. 152. Furthermore, as stated in the NPRM, 6 of
11 manufacturers whose owner's manuals NHTSA reviewed indicated that
their AEB system have a minimum speed below 10 km/h. NHTSA is
encouraged that manufacturers are choosing to have lower speed
thresholds for AEB functionality.
As for frontover crashes, NHTSA agrees with Consumer Reports about
the importance of understanding driver visibility and about the need to
reduce such crashes. Additional research is needed to develop accurate
and rigorous methods of evaluating direct visibility

[[Page 39713]]

from the driver's seat. Research is also needed to better understand
the safety problem and the scenarios associated with forward blind
zones and frontover crashes. Beginning in January 2023, two new non-
traffic crash data elements related to backovers \51\ and frontovers
were added to the agency's Non-Traffic Surveillance System, which will
enhance evaluation of the scope and factors associated with frontover
crashes.
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\51\ NHTSA has previously defined backover crashes as crashes
where non-occupants of vehicles (such as pedestrians or cyclists)
are struck by vehicles moving in reverse. See https://www.federalregister.gov/documents/2014/04/07/2014-07469/federal-motor-vehicle-safety-standards-rear-visibility.
---------------------------------------------------------------------------

2. Maximum Activation Speed
Comments
The National Transportation Safety Board (NTSB) supported the
proposed requirements for FCW, specifically pertaining to the necessity
of the warning at all speeds above 10 km/h, but the NTSB stated that
FCW activation must never delay AEB engagement. NTSB stated that its
support was rooted in several NTSB investigations of vehicles operating
in partial automation mode at the time of the crash.
In contrast, many commenters raised substantial concerns about the
proposed NPRM requirement that FCW and AEB function, at least at some
level, at all speeds and under all environmental conditions. Among
these concerns was that the requirement would not meet various aspects
of the Safety Act.
The Alliance disagreed with the agency setting undefined
performance requirements that are not stated in objective terms
consistent with 49 U.S.C. 30111 and urged NHTSA to provide
clarification when issuing a final rule that compliance verification
will be measured only by defined test procedures that meet established
criteria for rulemaking. It objected to what it viewed as undefined
performance requirements without a clearly demonstrated safety need
that create significant challenges from a product development
perspective, making it unclear whether or how NHTSA might seek to
verify compliance. Without defined and objective criteria, the Alliance
thought that policy uncertainty would create ambiguity about potential
enforcement actions as there would be no clear parameters to reliably
measure performance.
The Alliance suggested that a defined upper bound or maximum
operational speed for the AEB/PAEB system was needed due to the
possible unstable vehicle dynamics that could result from hard braking
at very high speeds. Furthermore, the Alliance opposed open-ended
performance requirements through regulation without objective test
procedures, noting that it becomes increasingly more challenging to
provide significant levels of speed reductions at higher speeds, and it
viewed the expectation that manufacturers are capable of providing
undefined levels of avoidance at all speeds as neither practicable nor
reasonable. According to the Alliance, requirements that exceed the
current speed ranges must be supported by relevant data to support
practicability and must include defined and objective test procedures.
The Alliance noted that the complexity of designing systems capable of
going beyond what the agency proposes to test would likely result in
significant development costs that are not accounted for in the
agency's cost-benefit analysis and that would add unnecessary costs for
consumers, while diverting research and development efforts from other
priority areas that may yield greater improvements in vehicle safety.
Multiple automakers expressed similar concerns, some recommending
that NHTSA limit AEB activation to maximum speeds and several
specifying suggested upper bounds. For example, Honda suggested that
NHTSA limit AEB activation to when the vehicle is traveling at maximum
135 km/h (84 mph) when approaching a lead vehicle traveling at maximum
75 km/h (47 mph) and limit pedestrian AEB activation to when the
vehicle is traveling at maximum 88 km/h (55 mph). Porsche suggested
that for the lead vehicle, DBS apply to speeds above 100 km/h (62 mph)
and for pedestrians to speeds above 65 km/h (40 mph), and that crash
imminent braking (CIB) be required to operate between 10 km/h (6 mph)
and 100 km/h (62 mph) for lead vehicle and between 10 km/h (6 mph) and
65 km/h (40 mph) for pedestrian. Porsche also provided suggested
regulatory text.\52\
---------------------------------------------------------------------------

\52\ https://www.regulations.gov/comment/NHTSA-2023-0021-0868.
---------------------------------------------------------------------------

NTSB expressed similar concerns about the need for testing, stating
that without a dedicated test protocol or an explicit statement about
the extent of operational functionality, broader capabilities (above
the testing requirements) remain only presumed and not necessarily
expected. NTSB encouraged NHTSA to clarify its intent and expectations
for system performance in scenarios and conditions outside the proposed
test-track compliance testing by considering additional testing or
other compliance tools to examine the performance of AEB systems under
other real-world conditions, and particularly whether the operational
functionality would extend to non-tested hazards such as traffic safety
hardware, bicyclists and motorcyclists, and vehicles with untested
profiles or at varying angles and offsets.
Commenters raised potential technical challenges to effective
implementation of the proposed requirement. For example, Honda was
concerned about AEB and radar sensor limitations when operating at high
speeds--mainly the complex interdependency between speed and the
distance and accuracy at which objects must be detected to be avoided
(or even to mitigate a crash). Honda noted that higher speeds mean that
objects will need to be detected at greater distances, and at greater
distances there is less image resolution, greater positional error, and
greater impact from things like roadway geometry. Honda and Porsche
stated that requiring braking to occur at unrestricted high speeds
leads to misidentification of objects and increases false positive
activations.
Honda further asserted that camera resolution is limited by the
pixel count on the image capture chip and that at longer distances, the
number of pixels for an object will be reduced, resulting in blur that
makes it difficult to detect objects (the blur can be further
exacerbated by the designed focal length of the lens). Further, Honda
stated that a higher resolution can be achieved only through new sensor
hardware that would require further developmental work as well as more
processing power, including a change of imaging processing electronic
control unit (ECU). Honda stated that for camera-radar fusion systems,
small errors in the fusion algorithm are amplified at higher speeds
(due to the longer distances) and could compromise the system's
performance. Additionally, according to Honda, these reductions in
sensor accuracy significantly increase the risk of misidentification of
potential objects and may lead to excessive false positive activations,
potentially creating negative safety consequences. This could include
situations where the system mistakenly recognizes the same lane as the
adjacent lane or roadway objects as other vehicles.
Other commenters also raised concerns about the potential for false
activations caused by the need for AEB to operate at very high speeds.
For example, Volkswagen commented that false activation becomes more of
a risk as speeds increase, and that these risks

[[Page 39714]]

are not controllable, as defined in ISO 26262.
Commenters raised concerns about whether braking was the most
appropriate avoidance maneuver in high-speed scenarios. Honda was
concerned that AEB activation might interfere with other technologies
such as the Automatic Emergency Steering. Mitsubishi, and Toyota echoed
the Alliance's concern that in some situations AEB activation while
traveling at high speed may induce unstable vehicle dynamics.
Mitsubishi stated that these situations may occur due to unfavorable
interactions with road surface conditions, road curvature, or for other
unpredictable reasons. Mitsubishi thought that such activation could
also lead to unexpected outcomes for a vehicle following the subject
vehicle.
Rivian stated that if post-crash review is used to assess
compliance, it may introduce a number of uncontrollable or subjective
variables into the compliance evaluation. Rivian opined that post-crash
review would necessarily involve evaluation of a motor vehicle that is
no longer a new motor vehicle and that may have been modified or
altered in a manner to affect the AEB performance. It further noted
that varying environment or roadway conditions could also impact the
AEB performance and, without a proper comparison using reference test
equipment, it would be difficult to identify discrepancies between the
expected AEB results and the actual results, limiting the technical
effectiveness of a post-crash review.
Commenters suggested a number of different solutions to resolve
their concerns. Most requested that the all-speeds requirement be
removed. Alternatively, Honda and others (as noted earlier) asked that
NHTSA establish a maximum speed at which AEB detection performance is
assessed according to an established test procedure. Volkswagen asked
that NHTSA exclude activation against vulnerable road users at high
speeds, believing it would decrease false positive rates significantly.
Volkswagen thought this could be justified as pedestrians would not be
expected on the roads with these higher speeds.
Agency Response
Authority Under the Safety Act
Various commenters asserted that performance requirements without
objective test criteria were inconsistent with the Safety Act's
requirements for objectivity and practicability. NHTSA believes that
these assertions reflect a misunderstanding of the proposal.
Essentially, NHTSA proposed specific performance requirements for AEB
within a defined range of speeds (accompanied by specific testing
procedures) and, separately, an equipment requirement--i.e., a
requirement for a functioning vehicle AEB system. The proposed
requirement for a functioning AEB system at all speeds was an equipment
requirement, not a performance requirement. Case law supports that
where a performance standard is not practical or does not sufficiently
meet the need for safety, NHTSA may specify an equipment requirement as
part of an FMVSS.\53\ Testing at high speeds is not practical due to
the dynamics of such testing and testing equipment limitations. As
detailed in the NPRM, the testing requirement upper speeds are based on
the capability to safely and repeatably conduct testing. The testing
devices can only be driven, and can only tolerate impacts, up to
certain speeds. These edge speeds are the main limiting factor for the
upper bound of the testing speeds, as testing above those speeds would
be impractical. NHTSA has previously specified an equipment requirement
without an accompanying test procedure. For example, under FMVSS No.
126, NHTSA issued an equipment requirement for understeer and explained
why a performance test for understeer was too cumbersome for the agency
and the regulated community.\54\ In the final rule for FMVSS No. 126,
NHTSA stated that historically, ``the agency has striven to set motor
vehicle safety standards that are as performance-based as possible, but
we have interpreted our mandate as permitting the adoption of more
specific regulatory requirements when such action is in the interest of
safety.'' \55\
---------------------------------------------------------------------------

\53\ Chrysler Corp. v. Dep't of Transp., OT, 515 F.2d 1053 (6th
Cir. 1975) (holding that NHTSA's specification of dimensional
requirements for rectangular headlamps constitutes an objective
performance standard under the Safety Act).
\54\ 72 FR 17236 (Apr. 6, 2007).
\55\ Id. at 17299.
---------------------------------------------------------------------------

There are other FMVSS that contain equipment requirements,
sometimes in addition to performance requirements. FMVSS No. 111 has
several requirements that are equipment requirements. S5.1 of FMVSS No.
111 requires that each passenger car be equipped with an inside
rearview mirror of unit magnification, which is the equipment
requirement without an associated test procedure. S5.3 requires that
any vehicle that has an inside rearview mirror that does not meet the
performance requirements for field of view included in S5.1.1 must also
have an outside rearview mirror meeting certain performance
requirements. FMVSS No. 135 requires that the service brakes shall be
activated by means of foot control. This is an equipment requirement in
an FMVSS that also has performance requirements. S5.1 of FMVSS No. 224,
``Rear impact protection,'' requires trailers and semitrailers with a
GVWR of 4,536 kg or more to be equipped with a rear impact guard
certified as meeting FMVSS No. 223, ``Rear impact guards.''
Technical Concerns
Various commenters raised concerns about technical limitations that
might create challenges for AEB systems at high speeds, such as sensor
limitations, false activations, and whether hard braking was an
appropriate response at higher speeds.
NHTSA is aware, from a review of owner's manuals, that many
manufacturers have equipped their vehicles with AEB systems that
activate at speeds higher than the testable ranges NHTSA proposed. As
an example, the 2022 Toyota Prius Prime owner's manual informs vehicle
owners that the maximum AEB activation speed for its system is 180 km/h
(112 mph). Other examples include: the 2023 Hyundai Palisade lists the
maximum AEB activation speed as 200 km/h (124.27 mph), the 2018 Tesla
Model 3 Dual Motor lists the maximum AEB activation speed as 150 km/h
(93.2 mph), the 2021 Volvo S60 lists the maximum AEB activation speeds
as 115 km/h (71.4 mph), the 2021 Ford Bronco lists the maximum AEB
activation speed as 120 km/h (74.5 mph), and the 2022 Lexus NX 250
lists a maximum AEB activation speed of 180 km/h (111.8 mph). This
demonstrates that it is common practice for AEB systems to function
above the testable range of speeds.
The agency considered comments asserting that higher travel speeds
require longer sensing ranges. However, the equipment requirement does
not specify a particular speed reduction or level of avoidance. The
agency considered the kinematics for an AEB system installed on a
vehicle that meets the track test requirements at 80 km/h without
manual braking. For a vehicle with automatic initiated deceleration
capabilities of 0.7g, in a lead vehicle stopped situation, the brakes
must be applied at a distance of approximately 37 m (equates to a time-
to-collision of 1.66 s). In such a situation, the vehicle's sensor
range would need to demonstrate capabilities at a distance of at least
37 m. In a similar rear end collision situation with the vehicle
traveling at 145 km/h and an identical detection

[[Page 39715]]

range of 37 m, the time-to-collision would be only 0.91 s. If the
vehicle applied the same 0.7g deceleration at the same 37 m distance, a
collision would not be avoided. A theoretical collision would occur
with the vehicle impacting the stopped vehicle at 119 km/h (74 mph).
However, the vehicle would have an AEB system that applied the brakes
when a crash is imminent, as the proposal would require.
Requiring that the AEB system function at higher speeds has
significant safety benefits. According to the injury risk curve used in
the FRIA available in this docket, the probability of a fatality
occurring in a rear-end collision where the striking vehicle is
impacting at 90 mph is almost 20 percent. That probability is reduced
to 6.8 percent for a travel speed of 74 mph. That reduction in fatality
risk is afforded with little to no additional sensing system
capabilities beyond what is required to satisfy the track tested
requirements. In other words, if the AEB system activates at 90 mph and
slows the vehicle down by just 16 mph, the risk of a fatality declines
significantly. If the system were deactivated at speeds above the test
procedure limit of 62 mph, many more fatalities would occur than if the
system is activated and functioning with the capabilities required to
satisfy the track tested requirements. Beyond 145 km/h (90.1 mph),
however, the expected safety benefits are greatly diminished, primarily
because very high travel speeds are relatively uncommon and currently
above legal operating speeds in the U.S.
NHTSA does recognize that pedestrian crash interactions are much
less straightforward kinematically than a lead vehicle rear-end crash
interaction. This is because the pedestrian may be moving in any number
of directions in front of the vehicle, including suddenly darting in
front of a vehicle, making detection and mitigation more challenging as
speed increases. In such situations, the agency agrees with commenters
that it is not practical to require an alert and braking at speeds
greatly above those for which the track test applies. For this reason,
this final rule reduces the speed range for pedestrian detection
functionality to any speed greater than 10 km/h (6.2 mph) and less than
73 km/h (45.4 mph). Similarly, for pedestrian AEB functionality, this
final rule reduces the upper end speed for which alerts and braking are
required to 73 km/h (45.4 mph). This speed range balances
practicability and safety.
Post-Crash Review
As for Rivian's comment on post-crash review, NHTSA can determine
compliance with this equipment requirement through visual observation
and other information, if requested from the manufacturer. Post-crash
review is an important tool to the agency. NHTSA acknowledges Rivian's
discomfort with post-crash review being considered as a primary tool
for compliance purposes, but NHTSA does not believe post-crash review
will be necessary to enforce this requirement. Instead, NHTSA believes
it can rely on visual observation, manufacturer test results used as a
basis for certification, and other information to determine whether a
vehicle meets this equipment requirement.
Conclusion
After careful consideration and in response to commenters stating
that there was not a safety need justifying the lack of a maximum speed
cap on this equipment requirement, NHTSA has decided to modify the
proposed requirement. The agency recognizes that while vehicles are
capable of very high speeds, the current maximum speed limit in the
United States is 85 mph. With this in mind and in response to comments
urging a speed cap for AEB operation, NHTSA decided to require that AEB
systems operate (i.e., warn the driver and apply the brakes) at speeds
up to 145 km/h (90.1 mph) for lead vehicle detection and 73 km/h (45.4
mph--based on the overall complexity of detecting and differentiating
between an imminent pedestrian crash and a pedestrian encounter that is
unlikely to result in a crash, such as when a pedestrian is located on
the sidewalk) for pedestrian detection. NHTSA also believes that
adopting this speed cap is consistent with the agency's analysis of the
safety problem and with NHTSA's goals of resolving as much of the
safety problems as possible.
NHTSA believes this requirement is feasible, particularly in light
of the absence of any performance requirements (for example, that a
vehicle brake automatically to avoid contact) other than at the speeds
tested in the performance requirements specified in this standard. This
final rule simply requires that an AEB system function to warn and
apply the brakes at speeds up to 145 km/h (90.1 mph) for FCW and lead
vehicle AEB. The agency is not preventing manufacturers from having FCW
activate at speeds above 145 km/h (90.1 mph). NHTSA is aware from
recent research into owner's manuals that many AEB systems operate at
speeds above the testable range, and NHTSA wants to ensure that
manufacturers have the flexibility to provide FCW (and AEB) at speeds
above those included in this final rule. This maximum required
activation speed addresses the concerns raised by commenters about a
requirement without an upper bound.
3. Environmental Conditions
In the NPRM, NHTSA explained that this equipment requirement was
intended to complement the performance requirements by, among other
things, ensuring that AEB systems continue to function in all
environments, not just the test track environment. Unlike track
testing, real world traffic scenarios may involve additional vehicles,
pedestrians, bicyclists, buildings, and other objects within the view
of the sensors and should not negatively affect their operation.
NHTSA received several comments expressing concern about the
unspecified environmental conditions included in the NPRM.
NHTSA is committed to establishing performance requirements that
are as reflective of the real world as possible, and that encourage
manufacturers to develop robust AEB systems with sufficient resiliency
to handle the widely variable scenarios they are intended to handle. In
general, NHTSA is concerned that high system brittleness will not
provide the maximum safety benefits and could be confusing to the
public because of expectations about how AEB systems should work. The
language of the NPRM sought to provide safety under environmental
conditions outside of those specified in a track testing environment.
That said, NHTSA agrees with commenters that the expectation that
the AEB system work in unspecified environments should be clarified for
manufacturers to certify that their vehicles will meet the equipment
requirement established by this final rule. There are environmental
conditions that may preclude the safe application of automatic braking,
and to a lesser extent warnings. However, the complexity of conditions
and combination of conditional factors make it difficult to clearly
enumerate those conditions. Therefore, this final rule now clearly
specifies the conditions in which the systems are expected to perform
to meet the equipment requirement are those conditions specified for
testing the performance requirements. Notwithstanding this specificity,
NHTSA encourages manufacturers to continue working

[[Page 39716]]

toward delivering AEB systems that are robust and that function in as
many real-world environments as possible.
The Utah Public Lands Alliance commented that the proposed rule did
not take into account the complexities of off-road environments, such
as obstacles, mud, rocks, and varying slopes, which may render the AEB
less effective or even cause false alarms, disrupting the driving
experience. NHTSA notes that the final rule does not include off-road
environments as a required aspect of AEB performance because the
agency's authority under the Safety Act focuses on the on-road
environment.

E. AEB System Requirements (Applies to Lead Vehicle and Pedestrian)

1. Forward Collision Warning Requirements
Because the window of time that FCW affords a driver in a crash-
imminent situation is small, the proposed warning characteristics were
intended to facilitate quick direction of the driver's attention to the
roadway in front of them and to compel the driver to apply the brakes
assertively. The FCW criteria proposed were based on many years of
warning research and vehicle crash avoidance research conducted by
NHTSA and others as described in the NPRM. The criteria seek to achieve
an effective warning strategy that is consistent across vehicle models
and proven by research to promote the highest likelihood of drivers
quickly understanding the situation and responding efficiently to avoid
a crash.
Comments
Commenters generally supported a requirement for an FCW to be
presented for lead vehicle and pedestrian scenarios. However, a
majority of commenters preferred more flexibility of FCW implementation
than is afforded by the requirements, as summarized below.
Multiple commenters were opposed to the degree of specificity
included in the proposed FCW requirements. These commenters thought
that the state of varied implementation of FCW that exists currently
was sufficient. For example, Volkswagen opined that the regulation
``should specify the warning modes (visual, auditory, optionally
haptic), but leave the implementation up to the manufacturer if the
warning is easily perceivable and visually distinguishable from other
warnings.'' Volkswagen thought that variation in FCW strategy across
manufacturers would not be a problem since manufacturers ``explain
their warning strategy in their owner's manuals.'' Similarly, the
Alliance contended that U.S. customers may be ``already familiar with
the ISO symbol and flashing alert'' and that it ``would be beneficial
to safety'' for NHTSA to allow flexibility for manufacturers to select
the visual warnings deemed to be most effective in the context of the
overall vehicle HMI.
IIHS cited its own research as a basis for contending that the
proposed FCW ``design requirements are unnecessarily overly
prescriptive'' given that ``existing industry practices for FCW are not
only effective for preventing crashes but are also acceptable and
understandable to drivers.'' IIHS highlighted its crash data analyses
for FCW-equipped vehicles stating, ``Our analyses of police-reported
crashes and insurance loss data indicate that most FCW systems are
effective for preventing rear-end crashes despite disparate designs.
Cicchino (2017) examined rear-end crash involvement rates for vehicles
with FCW from five automakers relative to vehicles without the system.
The presence of FCW was associated with statistically significant
reductions in rear-end crash involvement rates for three of the five
automakers.''
Some commenters suggested that the FCW requirements should more
closely follow other related standards. Ford recommended establishing
FCW requirements similar to existing AEB regulations from Europe (UNECE
R152 \56\), Australia (ADR98 \57\), and Korea (KMVSS \58\) instead of
restricting the individual components of the warning. Hyundai opposed
``overly specifying details for FCW and oppose[d] the use of SAE J2400
standards (particularly 10-degree vision cone provision).'' Porsche's
comments sought additional flexibility and alignment with UNECE
Regulation No. 152.
---------------------------------------------------------------------------

\56\ UN Regulation No 152--Uniform provisions concerning the
approval of motor vehicles with regard to the Advanced Emergency
Braking System (AEBS) for M1 and N1 vehicles [2020/1597] (OJ L 360
30.10.2020, p. 66, ELI: http://data.europa.eu/eli/reg/2020/1597/oj).
\57\ Australian Design Rule, Vehicle Standard (Australian Design
Rule 98/01--Advanced Emergency Braking for Passenger Vehicles and
Light Goods Vehicles) 2021.
\58\ Korean Motor Vehicle Safety Standard (KMVSS) Article 15-3,
``Advanced Emergency Braking Systems (AEBS).''
---------------------------------------------------------------------------

Lastly, multiple commenters voiced support for standardization of
FCW characteristics. The GHSA indicated support for FCW
standardization, stating that ``increased consistency will bolster the
safety impact of these features as drivers become more accustomed to
what to expect and how to react when these systems are engaged.'' AAA
also expressed support for standardization, stating that ``consumers
would find it beneficial to standardize visual alert characteristics. .
. such as the location of the warning.'' AAA cited its previous testing
experience that found ``characteristics among vehicles significantly
vary with some warnings hardly noticeable relative to visual warnings
presented in other vehicles.'' As a result, AAA urged NHTSA to
``consider standardization requirements for visual alerts to promote
consistency and understanding for all drivers, particularly hearing-
impaired drivers who may not perceive an auditory signal.''
Agency Response
NHTSA notes the general support from commenters for requiring some
kind of FCW to be presented prior to AEB activation. The point of FCW
is to elicit a timely and productive crash avoidance response from the
driver, thereby mitigating or, if possible, avoiding the need for AEB
to intervene in a crash-imminent situation. The proposed FCW
characteristics outlined in the NPRM are based on more than 35 NHTSA
research efforts related to crash avoidance warnings or forward
collision warnings conducted over the past nearly 30 years. Other
research, existing standards (ISO Standards 15623 and 22839), and SAE
documents (J3029 and J2400) also were considered as input for the
proposed requirements. While multiple commenters sought flexibility for
automakers to use an FCW of their own preference in lieu of one
conforming to the proposed specification, no safety data were provided
concerning consumers' degree of understanding of the wide variety of
existing FCW implementations--just generalized statements about
consumer familiarity. NHTSA does not view these arguments as sufficient
to overcome the value of standardization as a means of ensuring
consumer familiarity.
Data from NHTSA's 2023 AEB testing showed that each of six test
vehicle models from different manufacturers used a different FCW visual
signal or symbol. Only one model used the ISO FCW symbol. FCW visual
symbols that differ by manufacturer and, in some cases across models
from the same manufacturer, are likely to lead to confusion among
consumers. The observed substantial variety in existing FCW
implementations highlights the need for improved consistency of FCW
visual symbols to increase efficient comprehension of crash-imminent
warnings by vehicle operators and aid them in understanding the reason
for

[[Page 39717]]

their vehicle's (or, indeed, an unfamiliar rental vehicle's) active
crash avoidance intervention. Allowing for individual design choices--
even those with positive safety records--does not address this
important safety consideration.
Such confusion has also been documented by past research. Research
by industry published in a 2004 SAE paper focused on comprehension
testing of active safety symbols and assessed the ISO FCW symbol and
the SAE J2400 FCW symbol to assess their ability to communicate the
idea, ``Warning: You may be about to crash into a car in front of
you.'' Results of that research showed the ISO FCW symbol to have 45
percent ``high comprehension'' and the SAE J2400 symbol to have 23
percent high comprehension. However, while high comprehension was noted
for the lead vehicle crash scenario, NHTSA is not aware of any data
supporting effectiveness of the ISO FCW symbol for communicating the
idea of an impending forward pedestrian crash.'' \59\
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\59\ Campbell, John & Hoffmeister, David & Kiefer, Raymond &
Selke, Daniel & Green, Paul & Richman, Joel. (2004). Comprehension
Testing of Active Safety Symbols. 10.4271/2004-01-0450.
---------------------------------------------------------------------------

NHTSA acknowledges the research by IIHS showing crash reduction
benefits from some existing FCW designs. IIHS research results found
that some automakers' FCW designs were associated with higher crash
reductions than others. However, this research did not evaluate FCW
characteristics by automaker or by model for vehicle models it studied
and whether such characteristics may have contributed to FCW
effectiveness differences, so care should be taken when drawing
conclusions. Regardless, while the IIHS studies have shown some
existing FCW in light vehicles are effective for preventing rear-end
crashes, research does not support an argument against taking other
measures to increase FCW effectiveness, as this action seeks to do. It
is likely that increasing the consistency of FCW characteristics and
standardization of the primary warning signals across vehicles and
models will lead to benefits beyond those documented to date due to
increased driver understanding of the meaning of FCW signals.
The agency disagrees with Volkswagen's comment that explanations in
the owner's manual adequately inform consumers about manufacturer-
specific FCW signals. A British study found that only 29% of motorists
surveyed had read their car handbook in full.\60\ That same study
examined owner's manual word counts and estimated that the time
required to read some of the longest would take up to 12 hours. An
April 2022 Forbes article states that ``the average new-vehicle's
owners' manuals, which, concurrent with the complexity of contemporary
cars, have become imposingly thick and mind-numbing tomes of what
should be essential information... remain unread in their respective
models' gloveboxes.'' \61\ With these concerns in mind, NHTSA does not
believe that owner's manual information is an acceptable substitute for
standardization of this important safety functionality across all
vehicles.
---------------------------------------------------------------------------

\60\ ``Car Handbooks Are Longer Than Many Famous Novels--Have
You Read Yours?'' https://www.bristolstreet.co.uk/news/car-handbooks-are-longer-than-many-famous-novels--have-you-read-yours/.
\61\ ``Here's Why Nobody Reads Their Car's Owner's Manual''
https://www.forbes.com/sites/jimgorzelany/2022/04/07/heres-why-nobody-reads-their-cars-owners-manual/?sh=2a76d5d4462d.
---------------------------------------------------------------------------

After careful review of these comments, NHTSA has decided to adopt
a majority of the proposed FCW requirements unchanged as described in
the following sections.
a. FCW Signal Modality
NHTSA proposed that FCW modalities and related characteristics of
auditory and visual components be the same for lead vehicle AEB and
PAEB performance, and that the FCW be presented to the vehicle operator
via at least two sensory modalities--auditory and visual. The FCW
auditory signal was proposed to be the primary means used to direct the
vehicle operator's attention to the forward roadway. NHTSA did not
propose to require a haptic FCW signal component but invited comment on
whether requiring FCW to contain a haptic component presented via any
location may increase FCW effectiveness or whether an FCW haptic signal
presented in only one standardized location should be allowed.
Comments
Of those commenting on FCW signal modality, all supported a
multimodal FCW signal strategy. Multiple commenters including NTSB,
Consumer Reports, Ford, GHSA, Honda, MEMA, and Porsche expressed
support for the combination of auditory and visual warning modalities
that was proposed by NHTSA. For example, NTSB expressed support for
visual and auditory warning, and noted several NTSB investigations in
which visual warnings were found to be ineffective in capturing
drivers' attention. GHSA expressed support for requiring standardized
auditory and visual warnings when a collision is imminent, believing
that increased consistency would bolster the safety impact of these
features. Ford supported an auditory and visual alert based on their
experience implementing an FCW system. Honda stated that a multimodal
auditory and visual warning provided sufficient redundancy. Consumer
Reports also highlighted the importance of providing a visual warning
for those who are hearing impaired, who are listening to music, or are
otherwise distracted.
The remaining supporters of the multimodal approach preferred the
flexibility to use any combination of possible modalities (auditory,
visual and haptic). These included the Alliance, ASC, Bosch, GM, HATCI,
and Rivian. For example, the Alliance agreed with the agency's
conclusion that the auditory signal should be the primary means of
communicating with the driver, but expressed support for allowing
warnings to be provided using any combination of two of the three alert
modalities, with a third allowable, but not required. ASC recommended
that the warnings be aligned with UNECE Regulation No. 152. ASC and ZF
also cited research showing FCW with auditory and haptic components
prompt a quicker driver reaction time than FCW with auditory and visual
components.
Ford and MEMA agreed that OEMs should be permitted to supplement
the primary auditory and visual FCW signal modalities with a haptic
warning component. Bosch encouraged NHTSA to include haptic as one of
the warning modes, citing the potential for advantages in loud
environments or with hearing impaired individuals. Volkswagen agreed
with NHTSA's proposal to not require an FCW haptic component, but
clarified that if haptic was required, then only two out of the three
warning types should be required. HATCI requested that NHTSA permit
haptic signals to be used as the primary or secondary warning, stating
that haptic warnings draw the driver's attention to the hazard without
requiring them to identify a warning symbol with their eyes.
Consumer Reports suggested that a haptic signal may cause driver
confusion because haptic steering signals are also used by many lane
departure warning systems, which activate more frequently. Along the
same line, Porsche noted its desire ``to avoid causing driver confusion
related to other safety systems where haptic signals may be more
appropriate (e.g.,

[[Page 39718]]

steering wheel vibration used for lane keeping).''
Agency Response
After consideration of the comments, NHTSA is moving forward with
the originally proposed requirements for a primary FCW auditory signal
and a secondary visual signal, while neither requiring nor prohibiting
a supplementary FCW haptic signal. While a few commenters expressed the
desire to require a haptic FCW signal, no supporting data were
provided. Therefore, NHTSA declines to make a haptic warning signal a
requirement. However, NHTSA cautions those interested in implementing
supplementary FCW haptic signals to take steps to ensure that the
haptic signal used will not be confused with those currently used in
association with systems not designed to elicit a forward crash
avoidance response, for example, lane-keeping driver assistance
features.
b. FCW Auditory Signal Requirements
NHTSA proposed that the FCW auditory signal would be the primary
warning modality and asserted criteria to ensure that the FCW would be
successful in quickly capturing the driver's attention, directing the
driver's attention to the forward roadway, and compelling the driver to
quickly apply the brakes. NHTSA proposed that the FCW auditory signal's
fundamental frequency be at least 800 Hz and that it include a duty
cycle, or percentage of time the sound is present, of 0.25-0.95, and a
tempo in the range of 6-12 pulses per second. This final rule also
includes FCW requirements that were discussed in the NPRM.
Specifically, the FCW auditory signal is required to have a minimum
intensity of 15-30 dB above the masked threshold.
Comments
GHSA, Honda, and Rivian supported the proposed standardized FCW
auditory signal requirements. Honda stated that the proposed tone,
tempo, and frequency would contribute to making this a distinct and
recognizable warning, especially if standardized across the fleet.
Rivian agreed that a common FCW auditory signal is necessary so that
drivers can easily recognize warning conditions across different
vehicle makers and models.
Multiple commenters, including the Alliance, Ford, Nissan, Porsche,
Toyota, and Volkswagen indicated a preference for more flexibility in
the allowed FCW auditory signal characteristics. More specifically, the
Alliance and Nissan stated that not defining the required sound level
and characteristics is consistent with UNECE Regulation No. 152. Ford
recommended that the manufacturer be provided with flexibility to
design FCW auditory warning signals. Ford stated that the parameters
for an audible alert are often tuned for different vehicle applications
or customizable by drivers. Both Porsche and Volkswagen contended that
consumers may be used to existing FCW auditory signals used in current
vehicles. Volkswagen further stated that allowing flexibility in FCW
auditory signal characteristics enables manufacturers to update or
adjust the warnings as technologies evolve.
Regarding FCW auditory signal distinguishability, IIHS recommended
that NHTSA consider IIHS's method for assessing auditory seat belt
reminders to ensure auditory FCWs are easily discerned by drivers
beyond ambient levels of sound inside the vehicle.
On the issue of FCW auditory signal deactivation, Hyundai MOBIS
encouraged NHTSA to consider permitting the audible warning to be
suppressed as long as the FCW visual warning remains illuminated.
Agency Response
The FCW auditory signal minimum intensity requirement was
inadvertently left out of the proposed regulatory text, although it was
discussed in the preamble of the NPRM. Multiple commenters addressed
the topic of FCW auditory signal intensity in their comments. While
multiple commenters disagreed with NHTSA's proposed FCW auditory signal
criteria, NHTSA's data from 2023 AEB testing also showed that some
existing systems already meet some of the FCW proposed requirements.
One vehicle, a 2024 Mazda CX-90, met all proposed FCW auditory
requirements. Two vehicles met all proposed auditory requirements
except the minimum intensity requirement of 15-30 dB above the masked
threshold. Two other vehicles met 3 of the 5 FCW auditory signal
requirements while the last vehicle met only 2 of the 5 requirements.
All six vehicles' FCW auditory signals met the proposed duty cycle
requirement and four of the six met the fundamental frequency
requirement. Some variety in AEB test vehicles' FCW auditory signals
was also seen. FCW auditory signal intensities above the masked
threshold spanned a range of 28.8 dBA and five of the six tested
vehicles did not meet the proposed intensity requirement. FCW auditory
signals fundamental frequencies ranged from 600 to 2000 Hz.
NHTSA believes that auditory signal intensities are especially
important for FCW because of the urgency of the crash-imminent
situation, the goal of compelling a driver to apply the brakes, and the
speed with which action is necessary. Additionally, the minimum sound
intensity is supported by research that provides a strong foundation
for this requirement. Commenters who did not support the proposed FCW
auditory signal requirements provided no data to document the
effectiveness of existing FCW auditory signals, nor the purported
benefits of permitting vehicle manufacturers to choose their own unique
FCW designs. While providing flexibility for design choices that have
been proven to increase safety is valuable, providing flexibility that
allows for differences related to branding or that just serves to make
a model unique does not add safety value.
Regarding Ford's comment expressing interest in the ability to
decrease FCW auditory signal intensity when the driver's alertness
level is confirmed to be high, NHTSA notes that the proposed
requirements provide leeway for manufacturers to implement a less
invasive advisory or preliminary alert that would precede the required
FCW. It also would not prevent multiple intensities that all meet the
minimum requirement in this final rule.
NHTSA disagrees with the suggestion by Hyundai MOBIS to permit the
auditory warning to be suppressed as long as the FCW visual warning
remains illuminated. As the FCW auditory signal is considered the
primary means of warning a potentially inattentive driver, allowing the
auditory FCW signal to be suppressed would undercut its important
safety function.
After considering the comments, NHTSA has decided to finalize the
proposed FCW auditory signal intensity discussed in the preamble of the
NPRM in this final rule.
c. FCW Auditory Signal Presentation With Simultaneous Muting of Other
In-Vehicle Audio
In the preamble to the NPRM, NHTSA explained its intent to require
muting or substantial reduction in volume of other in-vehicle audio
(i.e., entertainment and other non-critical audio information) during
the presentation of the FCW. This requirement would serve to ensure
that the FCW auditory signal is conspicuous to the vehicle operator and
detectable at the critical moment at which a crash avoidance response
by the driver is needed. However, this intended requirement was
inadvertently left out of the proposed regulatory text.
Comments
ASC, MEMA, and ZF supported the muting or reducing other in-vehicle

[[Page 39719]]

audio during an audio FCW alert because the FCW alert is the highest
priority in the vehicle and should override all other sounds. ASC and
MEMA suggested that FCW alert volume should rise with speed to overcome
external sounds like wind noise or road noise.
Honda, Porsche and Volkswagen opposed muting of other in-vehicle
audio during FCW presentation. Honda stated that, because environmental
sound levels can vary drastically, it is unnecessary to require audio
muting. Honda cited the lack of a sound level requirement for the FMVSS
No. 208 seatbelt warning as rationale for not needing such a
requirement for FCW. Porsche and Volkswagen suggested that it is the
driver's responsibility to ensure that in-vehicle audio does not
interfere with the driving task. Volkswagen cited the requirement of a
both a visual and audio warning as justification for not requiring
muting of in-vehicle audio. Volkswagen also questioned how to
accommodate other mandatory audio signals if these occur simultaneous
with the collision warning.
Agency Response
Regarding Honda's comparison to the FMVSS No. 208 auditory warning
signal requirement for fastening seatbelts, NHTSA does not believe the
two requirements are comparable. The immediate consequences associated
with an impending forward crash are not comparable to those associated
with vehicle occupants fastening seat belts at the start of a drive.
In response to concerns expressed by Volkswagen and Porsche about
addressing multiple simultaneous auditory signals, NHTSA will clarify
that the audio required to be muted would be any audio for other than
crash avoidance or safety purposes, such as music or other
entertainment related audio.
Regarding the assertions by both Porsche and Volkswagen that
drivers are responsible for ensuring that in-vehicle audio system use
does not interfere with the driver's full attention to the driving
task, the situations in which FCW is expected to emit sound are urgent
enough that the most attentive driver would need to be able to hear the
auditory signal. NHTSA does not believe that attention or inattention
is the crux of the issue, though inattention could complicate a
driver's response. It is important to ensure that the FCW auditory
signal is audible even when sound levels from in-vehicle sources are
high.
Although the requirement to mute other in-vehicle audio during the
presentation of the FCW was inadvertently left out of the proposed
regulatory text, NHTSA is including such a requirement in this final
rule. Similar to the issue of auditory intensity, multiple commenters
addressed the topic of muting. The requirement will be finalized to
require that in-vehicle audio not related to a safety purpose or safety
system (i.e., entertainment and other audio content not related to or
essential for safe performance of the driving task) must be muted, or
reduced in volume to within 5 dB of the masked threshold, during
presentation of the FCW auditory signal. This specification will serve
to ensure that the amplitude of the FCW auditory signal is at least 10
dB above the masked threshold (MT) to preserve the saliency of the
auditory warning.\62\
---------------------------------------------------------------------------

\62\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M.,
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December).
Human factors design guidance for driver-vehicle interfaces (Report
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety
Administration. ``The amplitude of auditory signals is in the range
of 10-30 dB above the masked threshold (MT), with a recommended
minimum level of 15 dB above the MT (e.g., [1, 2, 3]).
Alternatively, the signal is at least 15 dB above the ambient noise
[3].''
---------------------------------------------------------------------------

d. FCW Visual Symbol Requirements
NHTSA proposed that FCW visual signals must use the SAE J2400
(2003-08) symbol.\63\ The SAE J2400 symbol relates the idea of an
impending frontal crash without depicting a particular forward object
and, as such, is readily applicable to both lead vehicle and pedestrian
scenarios. The FCW visual signal would be required to be red, as is
generally used to communicate a dangerous condition and as recommended
by ISO 15623 and SAE J2400 (2003-08). Because the FCW visual signal is
intended to be confirmatory for the majority of drivers and because
NHTSA-sponsored research \64\ has shown that instrument-panel-based
crash warnings can draw drivers' eyes downward away from the roadway at
a critical time when crash avoidance action may be needed \65\ the
symbol would be required to be steady burning.
---------------------------------------------------------------------------

\63\ SAE J2400 2003-08 (Information report). Human Factors in
Forward Collision Warning Systems: Operating Characteristics and
User Interface Requirements.
\64\ DOT HS 812 191 September 2015, Evaluation of Heavy-Vehicle
Crash Warning Interfaces. https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf.
\65\ ``Evaluation of Forward Collision Warning System Visual
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547,
https://trid.trb.org/view/1430473.
---------------------------------------------------------------------------

Comments
Multiple commenters voiced support for standardization of FCW
characteristics. For example, the Governors Highway Safety Association
(GHSA) indicated support for FCW standardization, stating that
increased consistency will bolster the safety impact of these features.
AAA cited its previous testing experience that some warnings were
hardly noticeable relative to visual warnings presented in other
vehicles.
Multiple commenters were opposed to specificity included in the
proposed FCW requirements. These commenters thought that the state of
varied implementation of FCW that exists currently was sufficient. For
example, Volkswagen described the proposed warning strategy for AEB as
too prescriptive. Volkswagen thought the regulation should specify the
warning modes, but leave the implementation up to the manufacturer if
the warning is easily perceivable and visually distinguishable from
other warnings. Volkswagen thought that variation in FCW strategy
across manufacturers would not be a problem because manufacturers
explain their warning strategy in their owner's manuals. NADA, Nissan,
Mitsubishi, and Porsche also suggested manufacturers have more
flexibility to choose the form of visual warning.
The Alliance opined that NHTSA should allow flexibility for
manufacturers to select the visual warnings deemed to be most effective
in the context of the overall vehicle human-machine interface, which
could include ISO or SAE symbols, word-based warnings, or other
flashing or steady burning illumination as appropriate. The Alliance
stated that NHTSA has not presented data to indicate that any one
visual alert type or symbol is any more or less effective than another.
Consumer Reports supported standardization but recommended that a word
be used rather than a symbol.
Some commenters suggested that the FCW requirements should more
closely follow other related standards. Ford recommended establishing
FCW requirements similar to existing AEB regulations from Europe,\66\
Australia,\67\

[[Page 39720]]

and Korea \68\ instead of restricting the individual components of the
warning. Hyundai opposed the use of SAE J2400 standards, including the
symbol. Hyundai believed it was more appropriate to adopt ISO 15623.
Porsche's comments seek additional flexibility and alignment with UNECE
Regulation No. 152.
---------------------------------------------------------------------------

\66\ UN Regulation No 152--Uniform provisions concerning the
approval of motor vehicles with regard to the Advanced Emergency
Braking System (AEBS) for M1 and N1 vehicles [2020/1597] (OJ L 360
30.10.2020, p. 66, ELI: http://data.europa.eu/eli/reg/2020/1597/oj).
\67\ Australian Design Rule, Vehicle Standard (Australian Design
Rule 98/01--Advanced Emergency Braking for Passenger Vehicles and
Light Goods Vehicles) 2021.
\68\ Korean Motor Vehicle Safety Standard (KMVSS) Article 15-3,
``Advanced Emergency Braking Systems (AEBS).''
---------------------------------------------------------------------------

Hyundai MOBIS, Toyota, the Alliance, Ford, and Honda, disagreed
with the steady burning requirement for the FCW visual signal,
expressing support for allowing it to flash. Honda recommended aligning
with the specifications of ISO 15008.
Honda supported both visual symbol and word-based FCW options.
Honda recommended that NHTSA allow flexibility to continue using
already well understood text-based warnings like ``BRAKE!,'' which
Honda currently employs, reasoning that a well-designed warning would
instruct drivers what to do to avoid a hazard. Rivian also supported
allowing the use of the word, ``BRAKE,'' in lieu of an FCW visual
symbol.
Agency Response
After careful review of these comments, NHTSA has decided to adopt
the proposed standardized FCW visual warning requirements unchanged.
While multiple commenters sought flexibility for automakers to use an
FCW visual signal of their own choice rather than a standardized
signal, no safety data were provided concerning consumers' degree of
understanding of the wide variety of existing FCW implementations nor
any safety advantages or benefits of not standardizing the visual
symbol. The proposed FCW characteristics outlined in the NPRM are based
on more than 35 NHTSA research efforts related to crash avoidance
warnings or forward collision warnings conducted over the past nearly
30 years. Other research, existing standards (ISO Standards 15623 and
22839), and SAE documents (J3029 and J2400) also were considered as
input for the proposed requirements. NHTSA does not view the provided
arguments as sufficient to overcome the value of standardization as a
means of ensuring consumer familiarity and ensuring the applicability
of the chosen symbol to both lead vehicle and pedestrian scenarios.
Data from NHTSA's 2023 AEB testing showed that each of six test
vehicle models from different manufacturers used a different FCW visual
signal or symbol. Only one model used the ISO FCW symbol. FCW visual
symbols that differ by manufacturer and, in some cases across models
from the same manufacturer, are likely to lead to confusion among
consumers. The observed substantial variety in existing FCW
implementations highlights the need for improved consistency of FCW
visual symbols to increase efficient comprehension of crash-imminent
warnings by vehicle operators and aid them in understanding the reason
for their vehicle's (or an unfamiliar rental vehicle's) active crash
avoidance intervention. Allowing for individual design choices does not
address this important safety consideration.
Such confusion relating to automotive symbol comprehension has also
been documented by NHTSA research. Past research conducted by NHTSA to
assess comprehension of vehicle symbols including the ISO tire
pressure, ISO tire failure, and ISO engine symbols showed that while 95
percent of subjects correctly identified the engine symbol, recognition
percentages for the ISO tire pressure and tire failure icons were the
lowest of the 16 icons tested, 37.5 percent and 25 percent,
respectively.'' \69\ Research by industry published in a 2004 SAE paper
focused on comprehension testing of active safety symbols and assessed
the ISO FCW symbol and the SAE J2400 FCW symbol to assess their ability
to communicate the idea, ``Warning: You may be about to crash into a
car in front of you.'' Results of that research showed the ISO FCW
symbol to have 45 percent ``high comprehension'' and the SAE J2400
symbol to have 23 percent high comprehension. However, while high
comprehension was noted for the lead vehicle crash scenario, NHTSA is
not aware of any data supporting effectiveness of the ISO FCW symbol
for communicating the idea of an impending forward pedestrian crash.''
\70\
---------------------------------------------------------------------------

\69\ Mazzae, E.N. and Ranney, T.A. (2001). ``Development of an
Automotive Icon for Indication of Significant Tire Underinflation.''
Article in Proceedings of the Human Factors and Ergonomics Society
Annual Meeting [middot] October 2001. DOI: 10.1177/
154193120104502317.
\70\ Campbell, John & Hoffmeister, David & Kiefer, Raymond &
Selke, Daniel & Green, Paul & Richman, Joel. (2004). Comprehension
Testing of Active Safety Symbols. 10.4271/2004-01-0450.
---------------------------------------------------------------------------

Consumer Reports ``Guide to ADAS'' states that ``CR's most recent
survey data shows that industry-wide, only 48% of owners of vehicles
equipped with FCW say they understand how it works.'' \71\ NHTSA
believes that improved consistency of FCW visual symbols is important
to increase efficient comprehension of crash-imminent warnings.
---------------------------------------------------------------------------

\71\ Consumer Reports' Guide to ADAS Usability: Consumer
insights on understanding, use, and satisfaction of ADAS December
2022. https://data.consumerreports.org/wp-content/uploads/2021/09/consumer-reports-active-driving-assistance-systems-ux-guide-revised-december-09-2022.pdf.
---------------------------------------------------------------------------

NHTSA acknowledges the research by IIHS showing crash reduction
benefits from some existing FCW designs. IIHS research results found
that some automakers' FCW designs were associated with higher crash
reductions than others. However, this research did not evaluate FCW
characteristics by automaker or by model for vehicle models it studied
and whether such characteristics may have contributed to FCW
effectiveness differences, so care should be taken when drawing
conclusions. Regardless, the IIHS studies have shown some existing FCW
in light vehicles FCW systems are effective for preventing rear-end
crashes, research does not support an argument against taking other
measures to increase FCW effectiveness. It is likely that increasing
the consistency of FCW characteristics and standardization of the
primary warning signals across vehicles and models will lead to
benefits beyond those documented to date due to increased driver
understanding of the meaning of FCW signals.
The agency disagrees with Volkswagen's comment that explanations in
the owner's manual adequately inform consumers about manufacturer-
specific FCW signals. As noted previously, a British study found that
only 29% of motorists surveyed had read their car handbook in full.\72\
That same study examined owner's manual word counts and estimated that
the time required to read some of the longest would take up to 12
hours. An April 2022 Forbes article states that ``the average new-
vehicle's owners' manuals, which, concurrent with the complexity of
contemporary cars, have become imposingly thick and mind-numbing tomes
of what should be essential information . . . remain unread in their
respective models' gloveboxes.'' \73\ With these concerns in mind,
NHTSA does not believe that owner's manual information is an acceptable
substitute for standardization of this important safety functionality
across all vehicles.
---------------------------------------------------------------------------

\72\ ``Car Handbooks Are Longer Than Many Famous Novels--Have
You Read Yours?'' https://www.bristolstreet.co.uk/news/car-handbooks-are-longer-than-many-famous-novels--have-you-read-yours/.
\73\ ``Here's Why Nobody Reads Their Car's Owner's Manual''
https://www.forbes.com/sites/jimgorzelany/2022/04/07/heres-why-nobody-reads-their-cars-owners-manual/?sh=2a76d5d4462d.

---------------------------------------------------------------------------

[[Page 39721]]

Finally, as for the use of words instead of a symbol, as noted in
the NPRM, word-based FCW visual warnings are used by some U.S. vehicle
models including, ``BRAKE!,'' ``BRAKE,'' and ``STOP!''. SAE J2400 also
includes a word-based visual warning recommendation consisting of the
word, ``WARNING.'' With regard to this existing use of word-based FCW
visual warnings in some models, research by Consumer Reports noted in
its online ``Guide to forward collision warning'' found that for some
models, visual warning word use was found to be confusing to some
drivers surveyed. Specifically, survey respondents reported a common
complaint that ``their vehicle would issue a visual ``BRAKE'' alert on
the dash, but it wouldn't bring the car to a stop.'' \74\ While NHTSA
does find merit in the rationale for using an effective word-based
visual warning for FCW purposes, we have decided in favor of the value
of consistency across U.S. vehicles to promote consumer recognition of
a dedicated FCW symbol. This symbol-based strategy for the FCW visual
signal follows is consistent with the strategies of ISO 15623 and SAE
J2400 (2003-08).
---------------------------------------------------------------------------

\74\ ``Guide to forward collision warning: How FCW helps drivers
avoid accidents.'' Consumer Reports. https://www.consumerreports.org/carsafety/forward-collision-warning-guide/.
Accessed April 2022.
---------------------------------------------------------------------------

NHTSA notes, however, that this requirement does not preclude the
use of a word-based warning that supplements the required FCW symbol
presentation. In that event, NHTSA agrees with Honda and Consumer
Reports that the word, ``BRAKE!'', including the exclamation point, is
likely the best choice for effective communication to the driver the
need for them to apply the brakes. NHTSA believes, as has been
suggested by Consumer Reports, that there is a tendency for drivers to
interpret some words used as warnings as describing an action being
performed by the vehicle, rather than a command to the driver. To avoid
such confusion by the driver, NHTSA recommends that manufacturers
wishing to complement the FCW symbol with a word-based warning use,
``BRAKE!'' to aid in drivers interpreting the word as an instruction.
Finally, with respect to the steady-burning requirement, NHTSA does
not agree with commenters recommending that the FCW visual warning be
allowed to flash. As the FCW visual signal is intended to be secondary
to the FCW auditory signal, allowing the symbol to flash in an attempt
to draw the drivers' attention could actually draw the drivers' gaze
downward to the instrument panel rather than to the forward roadway at
a critical time for the driver to initiate a crash avoidance response.
After evaluation of the comments, the agency has determined to
retain the proposal requirement for the visual symbol from SAE J2400
(2003-08), ``Human Factors in Forward Collision Warning Systems:
Operating Characteristics and User Interface Requirements''
(Information report), to communicate the idea of an impending frontal
crash without depicting a particular forward object. With no comments
opposed to requiring the FCW visual signal to be presented using the
color red, NHTSA is also finalizing that requirement as proposed and
clarifying that it will apply to the required FCW symbol and any
manufacturer-chosen words to accompany the required symbol.
e. FCW Visual Signal Location Requirements
The agency proposed that the FCW visual signal be presented within
a 10-degree cone of the driver's forward line of sight.\75\ This
requirement is based on SAE J2400, ``Human Factors in Forward Collision
Warning Systems: Operating Characteristics and User Interface
Requirements,'' paragraph 4.1.14. This FCW visual signal location
guidance is also consistent with ISO 15623, which states that the FCW
visual signal shall be presented in the ``main glance direction.''
Multiple research studies provide support for a visual warning location
close to the driver's forward line of sight. NHTSA-sponsored research
also supports this requirement, showing that instrument-panel-based
crash warnings can draw drivers' eyes downward away from the roadway at
a critical time when crash avoidance action may be needed.\76\
Industry-sponsored research published in 2009 also indicates that an
FCW visual signal presented in the instrument panel can slow driver
response.\77\ The 10-degree requirement would also increase the
likelihood of FCW visual signal detection by hearing-impaired drivers.
---------------------------------------------------------------------------

\75\ Line of sight based on the forward-looking eye midpoint
(Mf) as described in FMVSS No. 111, ``Rear visibility,'' S14.1.5.
\76\ DOT HS 812 191 September 2015, Evaluation of Heavy-Vehicle
Crash Warning Interfaces. https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf.
\77\ ``Evaluation of Forward Collision Warning System Visual
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547,
https://trid.trb.org/view/1430473.
---------------------------------------------------------------------------

Comments
Consumer Reports and AAA supported the proposed requirement that
the FCW visual signal be presented in a location within a 10-degree
cone of the driver's forward line of sight. In contrast, multiple
commenters opposed the 10-degree cone requirement, some believing that
the requirement could only be met using a head-up display. A majority
of commenters who addressed this point requested that NHTSA consider
expanding the 10-degree cone of the driver's line of sight requirement
for FCW visual signal location.
FCA, Hyundai, Nissan, NADA, Rivian, and Volkswagen opposed the 10-
degree cone requirement. The Alliance disagrees that the SAE J2400
information report provides adequate justification for the 10-degree
requirement.
FCA thought the proposed requirement was impracticable. Rivian
recommended that the FCW visual signal be presented on the top location
of the driver instrument panel, in the instrument panel, or in a head-
up display unless NHTSA can demonstrate that the data indicates that
one location is clearly superior for driver perception. Toyota
requested that the cone size be expanded to allow for suitable
placement of the visual alert in areas such as the meter cluster or
multi-information display, which would still be clearly visible in
front of the driver.
Porsche recommended that NHTSA consider replacing the 10-degree
with an allowance of up to 30 degrees, arguing that this would
facilitate the use of long-established visual warning locations which
it viewed as sufficient to provide the necessary cues. Multiple
commenters, including Mitsubishi, the Alliance, and Honda, recommended
use of a 60-degree cone requirement. Mitsubishi explained that the 60-
degree value is based on a book chapter titled, Visual Fields, by R.H.
Spector, et al., which states the vertical viewing angle of humans to
be 60 degrees.
Agency Response
While many current vehicle models present an FCW visual signal
within the instrument panel, drawing a driver's eyes downward away from
the roadway in front of them to the instrument panel during a forward
crash-imminent situation is likely to have a negative impact on the
effectiveness of the driver's response to the FCW. NHTSA's research
indicates that a visual FCW signal presented in the instrument panel
can draw drivers' eye gaze downward away from the forward roadway and
slow driver response to a forward crash-

[[Page 39722]]

imminent event.\78\ Further, Industry-sponsored research published in
2009 also indicates that an FCW visual signal presented in the
instrument panel can slow driver response.\79\
---------------------------------------------------------------------------

\78\ DOT HS 812 191 September 2015, Evaluation of Heavy-Vehicle
Crash Warning Interfaces. https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf.
\79\ ``Evaluation of Forward Collision Warning System Visual
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547,
https://trid.trb.org/view/1430473.
---------------------------------------------------------------------------

Mitsubishi highlighted content from ``Visual Fields,'' by R.H.
Spector, et.al that states the vertical viewing angle of humans to be
60 degrees.\80\ Specter's chapter specifically states that ``a normal
visual field is an island of vision measuring 90 degrees temporally to
central fixation, 50 degrees superiorly and nasally, and 60 degrees
inferiorly.'' Mitsubishi contended that if the FCW visual warning is
displayed within this range, the driver will be able to recognize it.
However, the referenced Spector visual field information relates to
average humans' ability see objects presented before them and not
specifically to drivers' ability to detect and quickly respond to an
FCW visual signal within the potentially cluttered visual scene of a
driver's-view perspective. Research sponsored by NHTSA and industry,
respectively, has shown that instrument panel based visual crash
warnings can draw drivers' eyes downward away from the roadway at a
critical time when crash avoidance action may be needed and that an FCW
visual signal presented in the instrument panel can slow driver
response.^{81 82} Comparison to other warnings is not apt
because other most other warnings do not require as immediate of a
response as FCW.
---------------------------------------------------------------------------

\80\ Spector RH. Visual Fields. In: Walker HK, Hall WD, Hurst
JW, editors. Clinical Methods: The History, Physical, and Laboratory
Examinations. 3rd ed. Boston: Butterworths; 1990. Chapter 116. PMID:
21250064.
\81\ DOT HS 812 191 September 2015, Evaluation of Heavy-Vehicle
Crash Warning Interfaces. https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf.
\82\ ``Evaluation of Forward Collision Warning System Visual
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547,
https://trid.trb.org/view/1430473.
---------------------------------------------------------------------------

As the text of SAE J2400 states, locating the FCW visual signal
within a 10-degree cone could be accomplished in a top-of-dashboard
location, NHTSA did not intend to require presentation of the FCW
visual signal only via head-up display. To evaluate the potential
difficulties associated with attempting to meet this FCW visual symbol
location requirement, NHTSA gathered additional information regarding
what visual angle about the driver's forward line of sight could be
used to locate the FCW visual signal near the driver's forward line of
sight, such as within the upper center portion of the instrument panel,
without requiring substantial redesign of vehicles' instrument panels
or dashboards, or require a head-up display.
NHTSA gathered information regarding the driver's visual angle when
looking at the instrument panel for a set of 10 light vehicles. Eight
of the vehicles were model year 2022, one was from the 2021 model year,
and one was from model year 2023. Vehicle makes examined spanned a wide
range of manufacturers including Chevrolet, Ford, Honda, Hyundai, Jeep,
Nissan, RAM Subaru, Toyota, and Volkswagen. The vehicles examined also
spanned a range of vehicle sizes including two large pickup trucks.
NHTSA used a coordinate measuring machine to record within a single
coordinate system the locations of the upper and lower extents of the
active display area of each vehicle's instrument panel, as well as the
left and right extents of the instrument panel. These points were used
to locate the geometric center of the instrument panel. The eye
midpoint location for a properly seated 50th percentile male driver was
also located using an H-point machine and recorded. The 50th percentile
male driver size was used to represent the midpoint of the range of
possible driver eye midpoint locations across all driver sizes. This
full set of coordinate data was used to calculate visual angles between
the eye midpoint and each of the center and upper and lower extents of
the vehicles' instrument panels at their horizontal center. The plot
below depicts visual angle calculation results for the instrument panel
central upper edge, center point, and central lower edge for a 50th
male driver's point of view.

[[Page 39723]]

[GRAPHIC] [TIFF OMITTED] TR09MY24.022

Visual angle values for the instrument panel center point for these
vehicles were found to range from 15.7 to 18.5 degrees. Nine of the ten
vehicles were found to have instrument panel center locations that
reside within 18 degrees downward of the driver's forward horizontal
line of sight. Based on these data, NHTSA believes that revising the
FCW visual symbol location 10-degree requirement to an 18-degree
vertical angle would permit the large majority of current vehicle
designs to display a telltale-sized or larger FCW visual symbol in the
upper half of the instrument panel without any structural redesign or
necessity of using a head-up display. Therefore, NHTSA has decided to
expand the vertical angle to 18 degrees while retaining the 10-degree
horizontal angle. The 10-degree value is being retained for the
horizontal angle to preserve the FCW symbol's presentation at the
center of the driver's forward field of view to maximize its
perceptibility.
2. AEB Requirement
a. AEB Deactivation
NHTSA discussed the issue of AEB deactivation in various
circumstances, and the various ways it might become deactivated (i.e.,
manually or automatically). NHTSA used both ``disablement'' and
``deactivation'' in the proposal, intending that those terms mean the
same thing. The NPRM proposed prohibiting manual AEB system
deactivation at any speed above the proposed 10 km/h minimum speed
threshold for AEB system operation. NHTSA sought comment on this and
whether the agency should permit manual deactivation similar to that
permitted for ESC systems in FMVSS No. 126. NHTSA also sought comment
on the appropriate performance requirements if the standard permitted
installation of a manually operated deactivation switch.
Regarding automatic deactivation, NHTSA stated that it anticipated
driving situations in which AEB activation may not increase safety and
in some rare cases may increase risk. For instance, an AEB system where
sensors have been compromised because of misalignment, frayed wiring,
or other partial failure, could provide the perception system with
incomplete information that is misinterpreted and causes a dangerous
vehicle maneuver. In instances where a light vehicle is towing a
trailer with no independent brakes, or with brakes that do not include
stability control functions, emergency braking may cause jack-knifing,
or other dangerous outcomes. In the proposal, NHTSA stated that it was
considering restricting the automatic deactivation of the AEB system
generally and sought comment on providing a list of situations in which
the vehicle is permitted to automatically deactivate the AEB or
otherwise restrict braking authority granted to the AEB system.
In addition to these situations, NHTSA requested comment on
allowing the AEB system to be placed in a nonfunctioning mode whenever
the vehicle is in 4-wheel drive low or the ESC is turned off, and
whenever equipment is attached to the vehicle that might interfere with
the AEB system's sensors or perception system, such as a snowplow.
NHTSA requested comment on the permissibility of automatic deactivation
of the AEB system and under which situations the regulation should
explicitly permit automatic deactivation of the AEB system.
Comments
Several commenters discussed AEB deactivation. The City of
Philadelphia, the Richmond Ambulance Authority, DRIVE SMART Virginia,
the National Association of City Transportation Officials (NACTO),
Advocates for Highway and Auto Safety (Advocates), the Nashville
Department of Transportation and Multimodal Infrastructure, and the
City of Houston supported the proposed requirement to prevent AEB
deactivation. In general, they stated that allowing system deactivation
would diminish safety benefits.
In contrast, many commenters stated that AEB deactivation should be
allowed. For example, ASC, ZF, MEMA, NADA, Mitsubishi, Porsche, Aptiv
and Volkswagen suggested that the agency should follow the specific
deactivation criteria under UNECE Regulation No. 152. That regulation
requires at least

[[Page 39724]]

two deliberate actions to deactivate the AEB system, and the system
must default back to ``on'' after each ignition cycle.\83\ Toyota,
Porsche, and Hyundai stated that manual deactivation for AEB systems
should be similar to what is allowed for ESC systems in FMVSS No. 126.
Rivian stated that manual deactivation should be allowed via either a
software or hardware switch.
---------------------------------------------------------------------------

\83\ UN Regulation No 152--Uniform provisions concerning the
approval of motor vehicles with regard to the Advanced Emergency
Braking System (AEBS) for M1 and N1 vehicles [2020/1597] (OJ L 360
30.10.2020, p. 66, ELI: http://data.europa.eu/eli/reg/2020/1597/oj).
---------------------------------------------------------------------------

Advocates opposed allowing deactivation of AEB systems, but they
provided some suggestions for NHTSA if deactivation were allowed in
narrowly tailored instances for specific applications with strong
justification and supporting data. Advocates stated that any conditions
allowed for automatic deactivation must not enable a means to
intentionally deactivate the AEB system and suggest that any
deactivation should trigger the malfunction telltale and be recorded as
part of a data recording requirement. If NHTSA were to allow manual AEB
deactivation, Advocates thought the process should require multiple
steps while the vehicle is not moving and require drivers to engage in
a deliberate and significant effort (i.e. a driver should not be able
to disable AEB by pressing a single button). Advocates aligned with
other commenters in suggesting that if any AEB deactivation occur, the
system should default back to ``on'' at any new ignition cycle.
The Alliance, Honda, NADA, Porsche, and Volkswagen suggested that
the agency should allow manual deactivation to mitigate consumer
dissatisfaction. Honda and NADA also stated that not allowing
deactivation may lead to substantially higher false positive rates,
while AAA stated that allowing for automatic or manual deactivation
could increase consumer acceptance and minimize the perception that the
systems are overbearing. NADA also stated that AEB false positives are
a significant source of consumer complaints about AEB systems and that
only 59 percent of respondents to a Consumer Reports survey indicated
that they were satisfied with their AEB systems. The Alliance stated
that in many cases, the circumstances warranting AEB deactivation are
already described in vehicle owner's manuals or other information
sources, and that it supports the continuation of describing such
circumstances to the user.
ASC stated that for ADAS-equipped vehicles where the primary
operating responsibility belongs to the driver, AEB is an assist
function and the driver should be able to deactivate the AEB system if
required. ASC also stated that under extreme operating or environmental
conditions, the AEB system may be outside its operating design domain
and should automatically deactivate (temporarily) and that in some
situations such as testing, or service, the AEB system should be able
to be deactivated.
SEMA, Ford, The Alliance, Rivian, Volkswagen, and HATCI suggested
that there are likely several circumstances where deactivation of the
system may be needed to ensure a safe vehicle operation, including
track use, off-road use, and car washes. Some specific examples
suggested by commenters include the use of chains on tires for
traction, towing, four-wheel drive, low traction driving scenarios, and
off-roading. SEMA and Mitsubishi stated that on a vehicle towing a
trailer without an independent brake system, AEB activation may cause
jack-knifing or other dangerous conditions. MEMA stated that drivers of
many existing vehicles can currently disable their AEB system in cases
where the AEB system is predictably, but incorrectly, triggered by
objects or structures.
NTEA stated that there is a need to be able to deactivate AEB when
certain vocational equipment is attached in frontal areas where it
intrudes into the field-of-view of an AEB system. NTEA stated that
final stage manufacturers and alterers are not currently (nor
foreseeably in the future) able to move/reinstall/recalibrate these
systems to accommodate vocational upfits that can be in direct conflict
with how these systems need to function. NTEA uses snowplows as an
example of a vehicle equipment for which sensor relocation cannot
accommodate AEB. NTEA stated, as an example of how provisions for
deactivation could be included in the requirement, that one vehicle
manufacturer has previously created a method to detect the presence of
a plow blade in their electrical architecture, so that when the blade
is attached, AEB is deactivated. AEB functionality resumes when the
blade hardware is removed. NTEA provided examples of other front-
mounted equipment such as winches, sirens and push bumpers on emergency
vehicles that could cause unintended consequences with the system
reaction of AEB. Further, NTEA identified operational aspects of
emergency and first responder vehicles that merit more consideration
for AEB deactivation.
The Alliance and Porsche stated that NHTSA should provide
manufacturers with the ability to define automatic deactivation
criteria. While Volkswagen stated that NHTSA should provide a list of
situations where automatic deactivation is allowed it stated that this
list should not be mandatory and joined the Alliance and Porsche in
stating that OEM's should establish the situations where the AEB system
is permitted to automatically deactivate, or otherwise restrict braking
authority granted to the AEB system. HATCI did not specifically comment
on the list of situations, but stated that allowing manual deactivation
would provide affordances for unforeseen scenarios that industry and
NHTSA have not yet contemplated which would help futureproof against
situations that may not exist today. The Alliance stated that this
approach introduces additional complexity in terms of demonstrating
compliance with the standard. Porsche stated that providing a not
``overly intrusive'' deactivation warning message would be appropriate
and that the range of situations in which the systems would be
automatically deactivated be infrequent and of limited duration.
Finally, the Alliance also addressed whether the deactivation of
ESC may cause deactivation of AEB. While not encouraged, a driver
seeking to disable AEB may be left with no option but to turn both AEB
and ESC systems off under NHTSA's proposal, reducing potential safety
benefits from having the ESC system remain active.
Agency Response
In this final rule, NHTSA does not allow for vehicles to be
equipped with a manual control whose sole functionality is the
deactivation of the AEB system. NHTSA agrees with the commenters who
noted concerns about diminishing the safety benefits of this rule.
Harmonization alone is an insufficient justification for allowing a
control to deactivate the AEB system. Commenters have not explained why
there is a safety need of a dedicated deactivation control or why a
dedicated deactivation control would not diminish the safety benefits
of AEB. The agency also disagrees with ASC's assertion that AEB is an
``assist function,'' and even if true, that such a description would
serve as a justification for allowing a manual deactivation control.
NHTSA does not agree that any theoretical consumer dissatisfaction
is one of the circumstances that justify allowing manual deactivation.
AEB systems have been available on vehicles for many years. It is not
reasonable to assume that there will be consumer acceptance issues due
to the requirements of this final rule.

[[Page 39725]]

NHTSA is not persuaded by comments that suggest that not permitting
deactivation would lead to substantially higher false positive rates.
NHTSA recognizes that AEB false positives are a source of consumer
complaints, but NHTSA does not believe AEB deactivation is the solution
to the engineering challenges manufacturers with lower performing
systems might face in meeting this rule's requirements.
That said, NHTSA recognizes that there are certain circumstances
where deactivation may be appropriate, and the commenters raise several
situations where NHTSA believes automatic deactivation would be the
best approach. Examples of such a scenario include when a trailer is
being towed, or when a snowplow is attached to a pickup truck. AEB
activation while towing a trailer may be unsafe if the trailer does not
have brakes. A snowplow may interfere with the sensing capabilities of
the AEB system. In such cases, NHTSA expects that the manufacturer
would automatically disable AEB functionality when interference with
the sensing capabilities occurs. Using the example of towing, NHTSA
expects that the manufacturer would design AEB to scan for towing
connections and automatically disable AEB if it registers any.
NHTSA agrees that it is important for the AEB system to default
back to ``on'' after each ignition cycle, except in one circumstance--
in a low-range four-wheel drive configuration selected by the driver on
the previous ignition cycle that is designed for low-speed, off-road
driving. In that situation, NHTSA believes that reverting to the
manufacturer's original default AEB setting would not be necessary.
There is a similar exception for the ESC Off control.
NHTSA also agrees with the Advocates that any deactivation should
trigger the malfunction telltale because consistent illumination is
important to remind drivers that safety equipment (i.e., AEB) is not
functioning as the driver expects. Should the OEM design its systems in
a way where the AEB system would automatically deactivate when the
system detects that it cannot function properly (i.e., change
performance in a way that takes the AEB system out of compliance with
the requirements of the standard), then the driver must be alerted of
this performance issue through a telltale. This applies to partial or
full disablement of the system.
NHTSA does not agree with the Alliance that restricting the
installation of an ``AEB off'' control leaves a driver seeking to
disable AEB with no option but to turn both AEB and ESC systems off.
First, it is up to the manufacturer to decide if AEB is automatically
turned off when ESC is turned off. Second, while it is not restricted
by the FMVSS, it is the manufacturer's choice to install an ESC off
switch. Finally, the agency asserts that if a driver does use the ESC
off control for the purpose of turning off AEB, the restrictions
included in this final rule limit the potential safety impacts
particularly once the vehicle's ignition is turned off because AEB is
required to turn back on with each ignition cycle, except when using a
low-range four-wheel drive configuration.
While NHTSA understands commenters' concerns about emergency
vehicles, the Agency notes that flexibilities already exist for these
vehicles, and we anticipate those flexibilities would be appropriate
and sufficient to address these concerns. There are a number of ways
that owners, and purchasers of emergency vehicles for official
purposes, could modify their vehicles to fit the unique needs of
emergency responders. Currently, manufacturers have the ability to sell
upfit packages that provide the means, and instructions (upfit guides),
for an emergency responder to interact with various vehicle features,
including mandated safety features. A common example of these
modifications involves the modification of lighting equipment and the
activation of patterns which are not compliant with FMVSS No.108. While
a vehicle manufacturer cannot manufacture a vehicle for sale with such
lighting and activation patterns that fail to comply with FMVSS No.
108, Lamps, reflective devices, and associated equipment, an emergency
responder, as the owner of a vehicle, is not prohibited from making
modifications to the vehicle.\84\ In addition, this final rule allows
for the deactivation of AEB when ancillary systems that may affect AEB
performance are activated.
---------------------------------------------------------------------------

\84\ In the absence of an AEB mandate, some OEMs currently
facilitate deactivation for emergency responders; for example
``Available PreCollision Assist With Pedestrian Detection-- . . .
For unique law-enforcement demands, a switch allows the feature to
be temporarily disabled.'' https://www.ford.com/police-vehicles/hybrid-utility/, Accessed March 7th, 2024 at 10:20 a.m.
---------------------------------------------------------------------------

In summary, NHTSA agrees with those commenters expressing
opposition to broad inclusion of an on-off switch. The agency believes,
as do those commenters, that the lifesaving benefits would be
significantly compromised. However, some commenters noted that certain
vehicles are used in unusual environments or for unique purposes, and
their operation might be hampered by an AEB system that cannot be
deactivated. The agency has not included on-off AEB functionality for
emergency vehicles, as a broad group, as these purpose-built vehicles
already have flexibilities. However, the agency believes that one other
situation is appropriate for inclusion of on-off functionality--
vehicles used by law enforcement.
Law enforcement has unique needs that often necessitate some
differences in the configuration or functionality of their motor
vehicles. The motor vehicles they purchase may be purpose-built police
vehicles or unaltered vehicles available to the general public. In
either case, law enforcement has a critical need to deactivate AEB when
such vehicles are used in intervention maneuvers to disable a suspect's
vehicle or in security escorts and processions driving in tight
formation. For this reason, this final rule provides a limited
exception that allows the manufacture, or the modification after sale,
of vehicles that include the ability to activate and deactivate AEB for
vehicles owned by law enforcement agencies.\85\ Manufacturers should
work to directly provide an on-off capability for verified law-
enforcement-owned vehicles or make it as easy as possible for a third
party to do so on behalf of law enforcement, with appropriate security
safeguards, and NHTSA is committed to actively facilitating this
process. Should manufacturers fail to address this important need,
NHTSA may consider taking additional regulatory action. NHTSA
anticipates that law enforcement vehicles resold to other than law
enforcement entities will be restored to their original condition
(i.e., by disabling the on-off capability).
---------------------------------------------------------------------------

\85\ The agency does not have a precise estimate of the number
of vehicles that may be affected by this flexibility, but notes
that, when considered as part of the entire fleet, this effect is
likely to be de minimis.
---------------------------------------------------------------------------

NTEA's comment requests that NHTSA consider adding regulatory
compliance pathways for upfitters. NHTSA understands NTEA's concern
regarding glass replacement and the impact that has on FCW/AEB sensors.
As AEB is not a new system, this is not a new issue for glass
replacement upfitters. The agency is aware of glass replacement
upfitters that already work with manufacturers to ensure proper sensor
calibration. It is not expected that the requirements of this final
rulemaking will affect their ability to continue to collaborate as they
have been. NHTSA also expects that manufacturers might provide for
automatic deactivation for vocationally

[[Page 39726]]

specific equipment when it is in use, such as the snowplow example NTEA
provides in its comment.
As for the equipment installed for vocational vehicles, NHTSA
expects upfitters to avoid installing equipment that would result in
AEB no longer working (or malfunctioning). NHTSA expects that in rare
cases where no engineering solution may exist such as with snowplows,
that upfitters would leave final installation of this equipment to the
vehicle owners to avoid making inoperative required safety equipment.
In such situations, NHTSA expects that the malfunction indicator would
illuminate as a constant reminder to the driver that AEB is not
working. As discussed in other sections, NHTSA believes that this
consistent illumination is important to remind drivers that important
safety equipment (i.e., AEB) is not functioning as the driver expects.
b. Aftermarket Modifications
SEMA stated that while the proposed rule applies to motor vehicle
manufacturers and alterers of new passenger cars and light trucks, it
does not specify how aftermarket vehicle modifications and alterations
may impact AEB systems. SEMA stated that they seek guidance from NHTSA
on implementing FMVSS for AEB and PAEB and the legal obligations of
SEMA members who produce, install, or sell aftermarket parts, as well
manufacturers, installers, retailers, distributors, and independent
repair shops regarding the ``tampering/make inoperative'' provision (49
U.S.C. 30122).
NHTSA notes that SEMA's comment invokes two separate provisions of
the Safety Act because the situations of alterers and repair businesses
are different. NHTSA has issued several interpretations of the
obligations of both alterers and repair businesses, and the agency
summarizes those key points here.\86\
---------------------------------------------------------------------------

\86\ Letter to Antonio Salvetti (Dec. 29, 1994) https://
www.nhtsa.gov/interpretations/
10425#:~:text=An%20%22alterer%22%20is%20one%20who,such%20as%20paintin
g%2C%20or%20by; Letter to Alan Nappier, Earl Stewart Toyota (Apr 17,
2015). https://www.nhtsa.gov/interpretations/30122-make-inoperative-alan-nappier-april-14.
---------------------------------------------------------------------------

An ``alterer'' is defined as a person who alters by addition,
substitution, or removal of components (other than readily attachable
components) a certified vehicle before the first purchase of the
vehicle other than for resale.\87\ The Safety Act and NHTSA's
regulations require vehicle manufacturers certify that their vehicles
comply with all applicable FMVSSs (49 U.S.C. 30112; 49 CFR part 567).
NHTSA's regulations at 49 CFR 567.7 require the alterer to ensure that
the vehicle, as altered, conforms to the FMVSSs affected by the
alteration(s) and to certify to that effect in accordance with the same
section. Alterers make this certification by affixing a permanent label
to the altered vehicle identifying the alterer and the date of
alteration.
---------------------------------------------------------------------------

\87\ 49 CFR 567.3.
---------------------------------------------------------------------------

In contrast, a vehicle repair business is defined as a person
holding itself out to the public to repair for compensation a motor
vehicle or motor vehicle equipment. Repair businesses usually work on
vehicles after the time of first sale, which means that instead of
complying with the certification requirements like a manufacturer or
alterer, a repair business must ensure that it does not violate the
Safety Act's make inoperative prohibition. The Safety Act states that a
vehicle manufacturer, distributor, dealer, rental company or repair
business is prohibited from knowingly making inoperative any part of a
device or element of design installed in or on a motor vehicle that
complies with an applicable FMVSS.\88\ An entity does not need to have
actual knowledge that a device or element of design would be made
inoperative by the entity's modification in order for that modification
to violate section 30122.\89\
---------------------------------------------------------------------------

\88\ 49 U.S.C. 30122.
\89\ Letter to Alan Nappier, Earl Stewart Toyota (Apr. 17,
2015), https://www.nhtsa.gov/interpretations/30122-make-inoperative-alan-nappier-april-14.
---------------------------------------------------------------------------

Additionally, section 30122 does not require repair shops to
restore safety systems damaged in a collision to a new or pre-crash
condition.\90\ Instead, under section 30122, when any repair to a
vehicle is completed, the vehicle must be returned to the customer with
the safety systems capable of functioning at least as well as they were
able to when the vehicle was received by the repair shop.\91\
---------------------------------------------------------------------------

\90\ See, e.g., http://isearch.nhtsa.gov/aiam/aiam4681.html,
letter to Linda L. Conrad, January 19, 1990.
\91\ Nonetheless, NHTSA strongly encourages repair shops to
restore functionality to safety systems to ensure that the vehicles
will continue to provide crash protection for occupants during the
life of the vehicle.
---------------------------------------------------------------------------

Given the information above, NHTSA concludes the two types of
entities about which SEMA is concerned both have an obligation to
prevent a noncompliance with the FMVSS created by this final rule.
Since NHTSA is establishing a new FMVSS with this final rule, the same
rules of certification and make inoperative will apply, except for
narrow circumstances for law enforcement-owned vehicles.
NHTSA is aware that many law enforcement vehicles are modified
after purchase to meet the unique needs of law enforcement. Sometimes
this work is completed by in-house entities, and other times, this work
may be contracted out to third parties. If those third parties are the
entities listed in 49 U.S.C. 30122, they are prohibited from making
inoperative any system or element of design that is in compliance with
a FMVSS, including this new FMVSS. To ensure that law enforcement are
able to modify their vehicles to fit their unique needs, and to ensure
that third-party repair businesses are capable of assisting them, NHTSA
has added a make inoperative exemption in 49 CFR part 595 that permits
manufacturers, dealers,and motor vehicle repair businesses to modify a
vehicle owners by a law enforcement agency to provide a means to
temporarily deactivate an AEB system. This addition is complementary to
the additional text added in S5.4.2.1 and discussed in the proceeding
section.
c. No-Contact Requirement for Lead Vehicle AEB
The proposed performance criterion for all AEB tests involving a
lead vehicle is full collision avoidance, meaning the subject vehicle
must not contact the lead vehicle.
NHTSA requested comment on two alternatives to a no-contact
requirement for the lead vehicle performance test requirements. The
first alternative would be to permit low speed contact in NHTSA's on-
track testing. The agency requested comment on the appropriateness of
such a requirement, any factors to consider surrounding such a
performance level, and what the appropriate reduction in speed or
maximum impact speed should be. The other alternative discussed in the
proposed rule was a requirement that permits the vehicle to use
multiple runs to achieve the performance test requirements. This
alternative is discussed in the ``Permissibility of Failure'' section.
Comments
In response to the NPRM, the IIHS, the Advocates, NTSB, AAA,
Adasky, and Luminar, expressed support for the full collision avoidance
(i.e., no-contact) requirement in all proposed AEB tests. IIHS stated
that their evaluations of existing AEB systems indicated that some
current systems are completely avoiding collisions at the highest
speeds IIHS has tested, which is 70 km/h. Advocates stated that the
vehicles are

[[Page 39727]]

tested under nearly ideal conditions and, by requiring a no-contact
condition for success, the benefits of the system will be stronger
under less-than-ideal conditions in the real world. NTSB and AAA stated
that the no-contact requirement is consistent with the need for safety,
and potentially necessary to ensure test repeatability. Luminar stated
that they were concerned that regulating some degree of contact in
these scenarios presents significant concerns for test efficiency,
integrity and cost related to compliance. Luminar stated that the no-
contact performance is within the capability of existing technology.
Several commenters, including the Alliance, Honda, FCA, Nissan,
Volkswagen, SEMA, and MEMA stated that the proposed no-contact
requirement in lead vehicle AEB tests is not practicable at the
proposed test speeds. Many of these commenters suggested a hybrid
approach of collision avoidance at lower speeds and speed reduction at
higher speeds. Multiple commenters stated that the proposed test speeds
will require earlier intervention by AEB systems to meet the ``no-
contact'' requirement, which they state will cause various unintended
consequences, such as false positives due to test speeds or AEB
intervention at a time where evasive steering may still be possible.
Many commenters stated that the expectation of no contact in the
real world is not practical. The Alliance stated that while the
research indicated that certain vehicles performed better under certain
test conditions, the number of tests run, particularly at higher
speeds, is insufficient to make any reliable determination as to the
repeatability and reproducibility of testing and that the agency ran
only one test per vehicle at each of the different speed ranges in each
scenario. Many commenters also observed that no vehicle was found to
have met all the proposed requirements.
Further, the Alliance described two aspects of brake performance
that they suggested should be considered. First, they stated that peak
deceleration capability of the vehicle is generally limited by the tire
adhesion and is therefore not likely to be impacted by brake hardware
changes, and performance today typically exceeds the mandated
performance from FMVSS No. 135 or FMVSS No. 105. The second aspect of
brake performance which the Alliance stated must be considered is the
time factor to reach the target deceleration.
Honda, Nissan, and other commenters stated that the proposed test
requirements do not consider the trade-off between collision avoidance
through evasive steering and emergency braking, leading to increased
concerns for false activations. Further, Honda stated that to meet the
proposed higher speed no-contact requirements, current systems would be
forced to provide braking intervention with significantly reduced
recognition reliability and that current AEB systems would need to be
completely redesigned.
Bosch stated that its testing shows that when the speed reaches
approximately 75 km/h, there are reproducibility challenges with multi-
sensor fusion of the object in time to initiate AEB and avoid the
obstruction, and considerations should be made on how these
requirements align with current functional safety requirements.
Volkswagen stated that they conducted an analysis using the Crash
Investigation Sampling System (CISS) where data from rear-end crashes
were collected from Event Data Recorder (EDR) data. The results were
that there were no injuries above the Vehicle Abbreviated Injury Scale
(VAIS) of 3+ in this small sample, noting that this was a non-
statistically significant sample of 56 rear end crashes below a
relative collision speed of 50 km/h.
MEMA stated that they agreed with the NHTSA alternate proposal for
contact which, consistent with European regulations, allows low speed
contact during testing. MEMA suggested a no-contact test requirement at
speeds up to 25 mph (roughly 40 km/h), and a realistic speed reduction
requirement above this speed (i.e., collision mitigation). Hyundai
stated that a target deceleration rather than no contact should be used
as the appropriate criterion for assessing AEB performance.
HATCI stated that the requirements for damageability from 49 CFR
part 581 address the need to reduce severity of any impact following
activation of AEB, such that reductions in fatalities and injuries are
achieved without stipulating no contact. Further, HATCI stated that the
part 581 bumper standard speeds do not cause damage to the vehicle or
Global Vehicle Target (GVT) and are highly unlikely to cause injuries
to the vehicle occupants.
Mitsubishi stated the agency should allow for maximum contact speed
instead of no contact, especially for higher test speeds, as the NPRM's
proposed requirement would require OEMs to fully redesign their AEB
systems, including new hardware. Further, Mitsubishi stated that the
benefit for systems which allow a low speed, such as a 10 km/h, impact
to the rear-end of another vehicle can be considered comparable to no
contact in terms of fatal or severe injury likelihood. Mitsubishi also
stated that they opposed a regulatory requirement whose purpose appears
to be reduction of the test burden by seeking to avoid rebuilding the
strikable target when impacted. Therefore, Mitsubishi stated that they
suggest 1) allowing low speed contact, 2) eliminating the higher
approaching-speed test, and 3) securing reasonable headway distance,
particularly with higher speed of the decelerating lead-vehicle
scenarios.
FCA raised issues with whether the no-contact requirement was
appropriate for vehicles with greater mass. FCA provided a graph
developed from their research that suggests that as test weight went
up, the overall pass (contact) rate went down.\92\ FCA stated that this
means one of two things: heavier vehicles installed less capable AEB
systems or otherwise if all AEB systems were comparable, then the test
weight of vehicle hardware could be a dominant factor in the compliant
``no-contact'' outcomes.
---------------------------------------------------------------------------

\92\ https://www.regulations.gov/comment/NHTSA-2023-0021-0999,
see page 9.
---------------------------------------------------------------------------

Furthermore, FCA stated that the proposed requirements that the
subject vehicle under test ``does not collide'' is subjective. The soft
coverings over both devices will have dimensional variation as they
exhibit wrinkles and folds or fluttering. FCA stated that they do not
understand what ``not collide'' means in this context. FCA suggested
NHTSA investigate this concept and make a new proposal as to what
``collide'' means as an objective, regulatory concept.
Agency Response
This final rule adopts the full collision avoidance (i.e., no-
contact) requirement proposed in the NPRM, which requires that the
subject vehicle must not contact the lead vehicle in all AEB
performance tests listed in the regulation. After considering all
comments and for the reasons discussed below, the agency believes that
the proposed no-contact requirement continues to be the most
appropriate. NHTSA does not believe that further investigation is
necessary to determine what collide means, in the context of this rule.
No Contact Provides Maximum Safety Benefits and Is Consistent With the
Safety Act
As noted in the NPRM, one of the primary reasons for choosing the
no-contact requirement in lead vehicle AEB tests is to maximize the
safety benefits of the rule. Many commentors agreed

[[Page 39728]]

with the agency's decision to obtain maximum benefits to the public.
Advocates stated that allowing contact during AEB testing will lessen
the strength/benefit of the rule. Similarly, NTSB stated that the no-
contact requirement is consistent with the need for safety and should
be mandated to obtain the best possible safety outcome. Further, AAA
and NSC stated that the no-contact requirement could eliminate millions
of injuries and thousands of fatalities over a five-year period.
Alliance acknowledged that the alternative approaches proposed by the
organization could provide meaningful safety gains (not the best
benefit). As for additional benefits of the requirement, we agree with
Luminar that the no-contact requirement also provides economic benefit
by reducing the total cost of vehicle ownership with insurance savings.
NHTSA agrees with the commenters who stated that obtaining safety
benefits is crucial for this final rule. NHTSA agrees with IIHS that
some current systems are already completely avoiding collisions under
the proposed lead vehicle AEB testing more than five years before this
rule will take effect. One vehicle discussed in the additional research
section performed very well and passed all lead vehicle AEB
requirements except for only the most stringent condition under the
lead vehicle decelerating scenario--satisfying the requirements in two
out of five tests. Thus, the outcome of that additional confirmatory
testing is encouraging and demonstrates that these requirements are
practicable. The testing results provided by IIHS in their comment
provide NHTSA with additional evidence that the requirements are within
reach for manufacturers because the technology exists and the final
rule provides sufficient lead time.
The No-Contact Requirement Is Practicable
The commenters who opposed the no-contact requirement and asserted
that it is not practicable rely heavily on the 2020 testing and that no
single vehicle achieved compliance in any single run. This assertion
rests on misunderstandings of the applicable law and a failure to
consider the trajectory of the technology and its performance.
First, no single vehicle must meet every requirement for an FMVSS
to be considered practicable under the Safety Act. The Sixth Circuit in
Chrysler Corp. v. Dep't of Transp. provided detailed analysis of the
technology-forcing authority possessed by NHTSA and the legislative
history that reinforces the court's conclusion.\93\ The Sixth Circuit
stated:
---------------------------------------------------------------------------

\93\ 472 F.2d 659 (6th Cir. 1972).
---------------------------------------------------------------------------

``[the] explicit purpose of the Act, as amplified in its
legislative history, is to enable the Federal government to impel
automobile manufacturers to develop and apply new technology to the
task of improving the safety design of automobiles as readily as
possible.'' \94\ The Senate Report also states that Congress rejected
the Automobile Manufacturers Association's attempt to bind the rate of
innovation imposed by safety standards to the pace of innovation of the
manufacturers.\95\ Similarly, the House Report states that NHTSA should
consider all relevant factors when considering whether a safety
standard is practicable, ``including technological ability to achieve
the goal of a particular standard.'' \96\ The Sixth Circuit rightly
points out that there would be no need for NHTSA to consider
technological ability to achieve a particular safety goal if NHTSA was
limited to issuing standards that reflected the current state of
technology.\97\ The court ultimately ruled that NHTSA is empowered by
the Safety Act to issue FMVSS that require improvements in existing
technology or that might even require development of new
technology.\98\
---------------------------------------------------------------------------

\94\ Id. at 671, citing S.Rep. 1301, 89th Cong., 2d Sess., 2
U.S.Code, Cong. and Admin.News, 2709 (1966).
\95\ S.Rep. 1301, 89th Cong., 2d Sess., 2 U.S.Code, Cong. and
Admin.News, 2709 (1966), which states ``In fact, specific efforts by
the Automobile Manufacturers Association to tie the rate of
innovation imposed by safety standards to the pace of innovation of
the manufacturers were rejected by the House Committee on Interstate
and Foreign Commerce, and the reported bill proposed that safety
standards be ``practicable, meet the need for motor vehicle safety,
and be stated in objective terms.''
\96\ H.R. Rep. 1776, p. 16.
\97\ 472 F.2d at 672.
\98\ Id. at 673.
---------------------------------------------------------------------------

Second, NHTSA has evidence that AEB performance improved
dramatically between 2020 and 2023 model years. Considering the marked
improvement in AEB system performance demonstrated in NHTSA's
additional testing, NHTSA finds that manufacturers are already coming
close to meeting the requirements of this final rule.
The agency disagrees with commenters that the no-contact
requirement is not practicable because no vehicle in the agency's 2020
research met all lead vehicle AEB tests as presented in the NPRM. We
believe that the vehicles used in the 2020 research were designed with
the intention to meet the demands from the 2016 voluntary commitment
and the existing U.S. NCAP. As presented in the NPRM, these programs
demand a much lower level of AEB performance than those of this final
rule. For example, the highest test speeds of the 2016 voluntary
commitment and the NCAP are both 40 km/h (25 mph) in a lead vehicle
stopped test scenario. On the other hand, the highest subject vehicle
test speed of this rule for the same scenario is 80 km/h (50 mph)--much
higher than that of the programs. Even though the AEB systems were
designed with substantially low target performance goals, three out of
eleven vehicles in the 2020 research were able to meet the no-contact
requirement at the speed up to 72.4 kph (45 mph) in the lead vehicle
stopped test scenario.
NHTSA conducted additional AEB research with six model year 2023
vehicles (from six different manufacturers) using the performance
requirements and test procedures of this final rule.\99\ The results of
this additional research demonstrated that one vehicle was able to meet
the no-contact requirement at least once in all required lead vehicle
AEB test conditions. Thus, the technologies needed to make the AEB
systems which can meet the no-contact requirement and other performance
requirements of this final rule are currently available. IIHS also
observed similar results, which they assert indicate that some existing
AEB systems are able to completely avoid collisions in the required
lead vehicle AEB testing conditions.
---------------------------------------------------------------------------

\99\ NHTSA's 2023 Light Vehicle Automatic Emergency Braking
Research Test Summary, available in the docket for this final rule
(NHTSA-2023-0021).
---------------------------------------------------------------------------

Furthermore, in analyzing whether an FMVSS is objective,
practicable and meets the need for motor vehicle safety, NHTSA must
balance benefits and costs and consider safety as the preeminent factor
in its considerations.\100\ NHTSA believes that lowering the
performance requirement to one that allows for contact would fail to
treat safety as the preeminent factor for this final rule and otherwise
be inconsistent with the goals of the Safety Act.
---------------------------------------------------------------------------

\100\ See, e.g., Motor Vehicle Mfrs. Assn. of United States,
Inc. v. State Farm Mut. Automobile Ins. Co., 463 U.S. 29, 55 (1983)
(``The agency is correct to look at the costs as well as the
benefits of Standard 208 . . . When the agency reexamines its
findings as to the likely increase in seat belt usage, it must also
reconsider its judgment of the reasonableness of the monetary and
other costs associated with the standard. In reaching its judgment,
NHTSA should bear in mind that Congress intended safety to be the
preeminent factor under the Motor Vehicle Safety Act.'').

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[[Page 39729]]

Increasing Unintended Consequences
In the comments, vehicle manufacturers and equipment suppliers
expressed concern that the no-contact requirement may cause some
unintended consequences, such as increasing false positive activations
and taking away driver's authority at a high speed.
As for the false positives, the concern is based on a hypothetical
situation that the no-contact requirement might cause a vehicle to
prematurely activate the AEB system from a far distance where there is
not a true risk of an imminent crash. The rationale is that the vehicle
would be forced to initiate an early braking to achieve a full
collision avoidance. These comments represent a combination of
concerns--concerns with the no-contact requirement and concerns with
the maximum speed in the testable range. This section addresses only
the issue of no contact. Other related issues are addressed in the
appropriate sections.
NHTSA does not expect that false activation would occur for well-
designed systems. NHTSA recognizes that false activation could occur
when an AEB system has low accuracy and reliability. As mentioned
previously, we agree with Luminar and other commentors that no-contact
performance is within the capability of existing technology. For
example, Honda asserted that an AEB system will likely intervene
improperly when the road in front of a subject vehicle is curved to the
left and there is a vehicle parked on the right side of the road that
causes no risk of collision. If the subject vehicle is equipped with
sufficient technology to detect the shape of the road ahead, the AEB
system would not improperly activate based on the mere fact that a
parked vehicle appeared in the middle of AEB's field of view. There are
manners in which an algorithm can assess the shape of the road. The
system will also be continuously receiving more data as the vehicle
gets closer.
Another technical option is having redundant systems as suggested
in the Alliance's comment. Regardless of whatever technical solution
manufacturers choose, NHTSA does not believe that it should lower
performance to match that of poor performers. Rather, manufacturers
with poorly performing vehicles should strive to resolve their systems'
deficiencies so that they can perform as well as the market's better or
best performing vehicles.
Additionally, while this rule imposes performance requirements for
AEB systems, it does not specify how manufacturers must meet the
requirements. The agency is providing maximum flexibility to
manufacturers in designing AEB system for their vehicles. NHTSA
recognizes that different manufacturers have different economic and
practical realities that face their businesses. NHTSA principal concern
is with the safety outcome and not the path that a manufacturer chooses
to take to get to the required outcome. Given the various technical
options, selecting technology for their AEB systems and setting the
level of accuracy and reliability are at the manufacturers' discretion.
At the same time, the manufacturers should be responsible for any
safety-related defects in their vehicle products, in this case
potential false positive activations. Therefore, we expect that vehicle
and equipment manufacturers will mitigate and resolve any product
defect issues including potential false activation in their AEB
systems. NHTSA will continue to monitor complaints on AEB systems from
the public, including those involving false activations, and will
evaluate the risks they present.
NHTSA does not agree with the Alliance and other commenters that an
AEB activation at a high speed may remove a safer crash avoidance
option from drivers. The AEB system presumably only starts braking when
the system detects an imminent crash, which is the first thing NHTSA
expects a driver would do. While last-minute steering by the driver
intended to avoid a crash is another possibility, NHTSA is not
persuaded this is the safest option or that it is incompatible with AEB
activation. A steering maneuver to avoid a crash might succeed under
very limited circumstances. First, there must be another lane adjacent
to the primary lane where a subject vehicle and a target vehicle are
located. Second, a sufficient space must also be available in the
adjacent lane. Finally, the driver must have the ability to safely
maneuver a vehicle at such a high speed. Regardless, nothing in this
rule specifies what an AEB system must do when a driver executes a
steering maneuver to avoid a crash.
Global Harmonization Is Not Possible for No Contact Because it
Unreasonably Lowers the Safety Benefits Received by the Public
NHTSA received comments that requested NHTSA to reject the no-
contact requirement and adopt UNECE Regulation No. 152 requirements
that permit low speed contact. Consistent with NHTSA's longstanding
commitment to international harmonization \101\ and section 24211 of
BIL, NHTSA cooperates to the maximum extent practicable with respect to
global harmonization of vehicle regulations as a means for improving
motor vehicle safety.
---------------------------------------------------------------------------

\101\ https://www.federalregister.gov/documents/1994/03/08/94-5181/revision-of-the-1958-united-nations-economic-commission-for-europe-agreement-regarding-the.
---------------------------------------------------------------------------

NHTSA has been a leader in various international forums that impact
vehicle safety for decades. The primary forum in which NHTSA engages in
these activities is UNECE World Forum for Harmonization of Vehicle
Regulations (WP.29). This international work is crucial to NHTSA's
safety mission because it allows the agency to share its knowledge and
expertise with foreign counterparts around the world, and for NHTSA to
learn from its foreign counterparts. It also allows for NHTSA to
advocate for standards that meet NHTSA's robust requirements and
improve safety is measurable ways. Analysis of safety benefits provide
NHTSA with a good understanding of the expected impact of its
regulations. Such analysis is not necessarily required or conducted at
WP.29.
NHTSA does not interpret section 24211 of BIL as requiring that
NHTSA adopt harmonized regulations for the primary purpose of
harmonization. To adopt this interpretation would be inconsistent with
the text of section 24211 and the Safety Act. NHTSA interprets section
24211 as requiring NHTSA to promote safety in global forums. NHTSA
believes that ``as a means for improving motor vehicle safety'' is
intended to convey that the requirement to harmonize has the goal of
improving motor vehicle safety. In situations where adopting an
international or regional regulation would result in reducing motor
vehicle safety, NHTSA does not believe the agency carries any
obligation under the abovementioned section to adopt regulations that
result in lower performance.
UNECE Regulation No. 152 was drafted by entities under an agreement
to which NHTSA is not a party, and it was drafted years before NHTSA's
NPRM. The testing NHTSA has conducted in support of this rule indicate
that the industry has made substantial progress between 2020 and 2023
model years. NHTSA's adoption of more stringent requirements than
existing UN Regulations indicates NHTSA's commitment to maximizing
safety.

[[Page 39730]]

Variability and Compliance Margins
FCA's comment indicates that it is concerned both about variability
and about the compliance margins it thinks may be necessary for it to
ensure compliance with this rule. First, FCA commented that the no-
contact requirement would force early decisions and that the NPRM did
not discuss why, in multiple runs, vehicles can pass some but not all
tests without contacts. From NHTSA's perspective, the variability seen
in NHTSA testing is expected because the systems tested were not
designed to be compliant with the proposed requirements. As NHTSA has
seen through its NCAP testing, manufacturers design systems to meet
whatever thresholds are set, and when they do that, their vehicles are
designed to pass those tests. This suggests to NHTSA that the
variability in the NHTSA testing is due to the fact that no
manufacturer has designed their systems to meet all of these
requirements. While NHTSA understands that industry is concerned about
the stringency of the no-contact requirement, variability does not seem
to be at the heart of that issue.
FCA also raised concerns about the compliance margins it believes
may be necessary for its products to comply with the no-contact
requirement. Compliance margins are usually manufacturer dependent due
to a variety of reasons that include the fact that each manufacturer
establishes a different level of organizational risk acceptance and
each manufacturers' products are usually unique to that manufacturer.
As stated in the FRIA accompanying this rule, different manufacturers
may have differing compliance margins with which their companies are
most comfortable. Differing compliance margins and overall
organizational risk management practices can impact the product and
costs to make that product. Manufacturers are free to choose what
compliance margins make sense for their organization and their
products, and NHTSA does not dictate that. NHTSA establishes a minimum
level of performance and manufacturers are required to ensure that
their products meet that minimum level.
NHTSA's Testing Is Sufficient To Support This Rule
The testing conducted by the agency included the most common rear-
end crash scenarios across several speeds and included a range of
vehicle types and both camera and radar and camera fusion systems. In
the case that the vehicle met the requirements (no contact) for a
specific crash scenario and speed, testing continued at higher speeds.
For the Lead Vehicle AEB testing, each vehicle was tested five to seven
times for each scenario and speed combination. For the PAEB testing,
each vehicle was typically tested five times for each combination of
scenario, speed, and lighting condition.
In the absence of unlimited time and resources, it is not possible
to test every vehicle across each combination of scenario, speed, and
condition. Further, contact with a target object has the potential to
compromise future test runs. Even relatively low speed impacts can
result in a misalignment of forward-looking sensors, particularly those
mounted behind lower trim and/or the grill. As a result, subsequent
(i.e., post impact) tests may not be representative of the vehicle
condition at time of first sale.
The vehicles included in the testing conducted by the agency
include a variety of body styles including heavier vehicles such as
SUVs and pick-up trucks. The heavier vehicles included in testing NHTSA
used to support the NPRM were Ford F-150 SuperCrew, Mercedes-Benz GLC
300, Hyundai Palisade, Audi Q5, and Range Rover Sport. The vehicles
that NHTSA tested also included a mix of camera only and radar and
camera fused systems utilized by model year 2020/19 vehicles.
Furthermore, NHTSA performed additional confirmatory testing that
included 2023 model years. This testing showed that the models tested
performed even better than those in 2020, which supports NHTSA's
position that this rule is not only achievable but very close to being
within reach for many manufacturers. NHTSA believes that the research
from 2020 and 2023 is sufficient to support this final rule.
d. No-Contact Requirement for Pedestrians
Similar to the lead vehicle AEB performance test requirements,
NHTSA proposed that PAEB-equipped vehicles must completely avoid a
collision with a pedestrian test mannequin during specific test track
scenarios. NHTSA requested comment on the same two alternatives to a
no-contact requirement for pedestrian performance test requirements.
NHTSA notes that the positions taken by commenters for both lead
vehicle AEB and PAEB are substantially similar, and therefore, much of
what was said in the previous section also applies. This section
primarily addresses issues specific to pedestrians.
Comments
IIHS stated that their evaluations of existing PAEB systems
indicated that some current systems are completely avoiding collisions
in the required PAEB testing conditions. IIHS stated that they began
evaluating PAEB performance in new vehicles during the day in 2019 and
at night in 2022. Furthermore, they stated that IIHS's PAEB ratings are
based on a mixture of the data submitted by manufacturers for
verification and the results from their internal testing. As of June
2023, IIHS stated that they rated 194 model year 2023 PAEB systems
tested during the day. Of those, 33 (17 percent) fully avoided the
pedestrian mannequin in every test condition. IIHS further stated that
of the 114 model year 2023 PAEB systems tested at night, 12 (11
percent) fully avoided the pedestrian mannequin in every test
condition.
MEMA commented that full avoidance is not reproduceable at higher
velocities in low light conditions and in obstructed scenes. Due to
external influences, MEMA contended that it is impossible to ensure
that every test run is performed under the exact same conditions in
this test, which is why it cannot be guaranteed that AEB will always
achieve its maximum performance.
The Alliance stated that they suggest that the agency set the
requirements of the regulation with the goal of minimizing the risk of
serious injury in cases where vehicle to pedestrian contact occur,
while providing for more certainty in making a determination to apply
the brakes for crash avoidance and mitigation. Based on available
research, the Alliance stated that establishing a no-contact
requirement up to 30 km/h and a residual relative speed contact
threshold not to exceed 25km/h would ensure the risks of sustaining a
MAIS 3+ injury is well below 10%. Further, The Alliance stated that
this exceeds the acceptable injury thresholds established in NCAP (for
achieving a five-star rating) as well as the recommendations of
Academic Expert Group for the 3rd Global Ministerial Conference on Road
Safety. The Alliance stated that the suggested hybrid approach which
would maintain the no-contact requirements at vehicles speeds up to 30
km/h but permit some level of contact if an acceptable speed reduction
were achieved would reduce the potential for false positives under real
world conditions.
Bosch stated that they wanted to address the ``no-contact''
requirement in performance testing and its implications for safety
systems, particularly in the

[[Page 39731]]

context of pedestrian dummy detection and reaction. Further, Bosch
stated that considering the challenge of detecting and reacting to the
pedestrian dummy, there are still reservations concerning the no-
contact requirement. Further, Bosch stated that they suggest that the
criteria for collision mitigation systems be based on a certain amount
of minimum speed reduction while considering injury-related
assessments, such as the Head Injury Criteria (HIC) or similar measures
(e.g., acceleration exerted on the body during crash).
Agency Response
After considering the comments, the agency has concluded that the
full collision avoidance requirement in PAEB tests, as proposed in the
NPRM, is most appropriate for this final rule.
First, we agree with commenters that pedestrians could suffer
severe injury at any speed in the testable range. Pedestrians are
particularly vulnerable when coming in contact with a vehicle of any
size. This is especially true when pedestrians are stuck by larger
vehicles such as SUVs and pickup trucks. NHTSA believes that the
increased vulnerability of pedestrians makes it even less desirable to
permit any vehicle-to-pedestrian contact within the testable range.
Second, the impracticability argument raised by Alliance, MEMA and
other manufacturers is not persuasive. That argument is primarily based
on the agency's 2020 PAEB research presented in the NPRM, in which no
vehicle met all required PAEB performance tests. The commenters assert
that this reflects that the existing AEB related technologies are not
ready for the level of PAEB performance required by this rule. However,
we disagree with the commentors and believe that the results of the
2020 research are not indicative of shortcomings in the overall
capability of the current PAEB technology. Rather, they are systems
designed to meet a lower level of performance.
The agency conducted PAEB research with six model year 2023
vehicles (from six different manufacturers) using the proposed
performance requirements and test procedures.\102\ The results
demonstrated that at least one vehicle was able to meet all performance
requirements of this final rule. To the extent others do not, NHTSA has
authority to issue technology-forcing standards when it is shown, as it
is here, that meeting the standard is practicable.
---------------------------------------------------------------------------

\102\ NHTSA's 2023 Light Vehicle Pedestrian Automatic Emergency
Braking Research Test Summary, available in the docket for this
final rule (NHTSA-2023-0021).
---------------------------------------------------------------------------

While the Alliance asserts that reducing impact speeds with
pedestrians below 25 km/h could reduce the risk of serious injury,
NHTSA believes that striking a person with a vehicle is not acceptable
at any speed under any conditions. NHTSA included pedestrians in this
rule because of their vulnerability and the trend of increasing
pedestrian fatalities. Accordingly, we believe that retaining the no-
contact requirement for the PAEB performance tests in the final rule is
the most appropriate to ensure the maximum safety of the pedestrians.
e. Permissibility of Failure
As an alternative to the no-contact requirement with a single run
that NHTSA proposed for lead vehicle AEB and PAEB, NHTSA sought comment
on permitting the subject vehicle to use multiple test runs to achieve
the performance test requirements. NHTSA provided background about how
NHTSA's crash imminent braking and dynamic brake support testing within
the New Car Assessment Program tests performance criteria, at the time
of NPRM publication, specify that the speed reduction requirements for
each test scenario must be met in at least 5 out of 7 tests runs. NHTSA
stated this approach would provide a vehicle more opportunities to
achieve the required performance and the agency more statistical power
in characterizing the performance of the vehicle.
The agency also requested comment on the number of repeated tests
for a given test condition and on potential procedures for repeated
tests. The agency further requested comment on the merits of permitting
a vehicle that fails to activate its AEB system in a test to be
permitted additional repeat tests, including a repeat test process
similar to that in the recent revisions to UNECE Regulation No. 152.
Finally, the agency requested comment on whether there should be
additional tests performed in the event no failure occurs on an initial
test for each series.
The Advocates, Forensic Rock and AAA oppose allowing repeated test
trials in all test situations. Forensic Rock stated test failures
should not be allowed when performing testing under ideal conditions.
AAA stated that repeated tests would lead to ambiguity around whether a
vehicle that has previously passed the test should be retested.
The ASC, ZF, Humanetics, MEMA, Bosch, Mitsubishi, the Alliance,
Porsche, Hyundai, Aptiv, Rivian, and Volkswagen all support allowing
repeated test trials. ASC, ZF, Humanetics, MEMA, Bosch, and the
Alliance specifically acknowledge that testing with a 5 out of 7
passing threshold for the speed reduction tests would be appropriate.
Rivian recommends running between 3 and 5 tests and averaging the speed
reduction achieved with a passing grade being given to vehicles that
average greater than a 50 percent speed reduction. The Alliance and
Porsche also recommend that a vehicle could pass after three
consecutive successful tests. ASC and ZF recommend that repeated trial
testing be used at speeds of 25 mph and higher. ZF recommends that the
speed reduction targets should be data driven based on speeds where
there is a severely limited risk of injury to pedestrians or vehicle
occupants. ZF, Porsche, Aptiv, Volkswagen and ASC also suggest the test
requirements be aligned with UNECE Regulation No. 152 speed reduction
requirements for daytime scenarios.
NHTSA is not including multiple test trials in this final rule.
NHTSA agrees with commenters that allowing for repeated test trials,
which would essentially permit a certain threshold of failures, under
ideal test conditions is not acceptable. NHTSA believes that a single
test run, and the expectation that a manufacturer pass all test runs if
NHTSA chooses to run the same test several times, provides the
performance consistency that consumers expect and safety demands. This
is particularly true given that NHTSA will be conducting testing in
idealized, controlled conditions when compared to real-world
situations. For many years, NCAP testing and other testing around the
world has permitted repeated test trials, and NHTSA believes that is
appropriate for a technology that is new or being developed. However,
for more mature systems with a long record of real-world use, NHTSA
believes that a single test run is necessary to provide the agency the
confidence that the performance it is regulating will perform as
consistently as possible.
NHTSA believes it is even more important that PAEB perform in a
single run with no contact due to the vulnerability of pedestrians in a
vehicle-to-pedestrian crash. First, the speed ranges in which PAEB is
expected to not contact a pedestrian mannequin during testing are lower
than they are for lead vehicle AEB. Second, as with the no-contact
provision, allowing for multiple runs is even more unacceptable for
vehicle-to-pedestrian crashes because pedestrians are more vulnerable
when being struck by a vehicle.

[[Page 39732]]

F. False Activation Requirement

NHTSA proposed to include two scenarios in which braking is not
warranted. The agency proposed that AEB systems need to be able to
differentiate between a real threat and a non-threat to avoid false
activations. The two proposed false activation scenarios were the steel
trench plate and the vehicle pass-through test scenarios.
1. Need for Requirement
NHTSA remains concerned that false activation events may introduce
hard braking situations when such actions are not warranted,
potentially causing rear-end crashes. The false activation tests
establish only a baseline for system functionality. They are by no
means comprehensive, nor sufficient to eliminate susceptibility to
false activations. Rather, the tests are a means to establish minimum
performance. NHTSA expects that vehicle manufacturers will design AEB
systems to thoroughly address the potential for false activations.
Vehicles that have excessive false positive activations may pose an
unreasonable risk to safety and may be considered to have a safety-
related defect. Previous implementations of other technologies have
shown that manufacturers have a strong incentive to mitigate false
positives and are successful even in the absence of specific
requirements.
The two proposed false activation scenarios are the steel trench
plate and the vehicle pass-through test scenarios. Both of these tests
include acceleration pedal release and testing both with and without
manual braking, similar to testing with a stopped lead vehicle. NHTSA
proposed that, during each test trial, the subject vehicle accelerator
pedal will be released either when a forward collision warning is given
or at a headway that corresponds to a time-to-collision of 2.1 seconds,
whichever occurs earlier. For tests where manual braking occurs, the
brake is applied at a headway that corresponds to a time-to-collision
of 1.1 seconds.
In the steel trench plate false activation scenario, a subject
vehicle traveling at 80 km/h (50 mph) encounters a secured 2.4 m (7.9
ft) wide by 3.7 m (12.1 ft) long steel by 25 mm (1 in) thick ASTM A36
steel plate placed flat in the subject vehicle's lane of travel, and
centered in the travel path, with its short side toward the vehicle
(long side transverse to the path of the vehicle).
The pass-through test, as the name suggests, simulates the subject
vehicle encountering two vehicles outside of the subject vehicle's path
that do not present a threat to the subject vehicle. The test is
similar to the UNECE Regulation No. 131 and UNECE Regulation No. 152
false reaction tests.\103\ In the pass-through scenario, two vehicle
test devices (VTDs) are positioned in the adjacent lanes to the left
and right of the subject vehicle's travel path, while the lane in which
the subject vehicle is traveling is free of obstacles.
---------------------------------------------------------------------------

\103\ UNECE Regulation No. 131 (Feb. 27, 2020), available at
https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2015/R131r1e.pdf; UNECE Regulation No. 152, E/ECE/TRANS/505/Rev.3/
Add.151/Amend.1 (Nov. 4, 2020), available at https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2020/R152am1e.pdf.
---------------------------------------------------------------------------

The two stopped VTDs are positioned parallel to each other and 4.5
m (14.8 ft) apart in the two adjacent lanes to that of the subject
vehicle (one to the left and one to the right with a 4.5 m (14.8 ft)
gap between them). The 4.5 m (14.8 ft) gap represents a typical travel
lane of about 3.6 m (11.8 ft) plus a reasonable distance at which a
vehicle would be stationary within the adjacent travel lanes.
Comments
ASC, MEMA, Hyundai, Volkswagen, Mitsubishi, and the Alliance for
Automotive Innovation submitted comments opposing the proposed false
activation tests. ASC stated that EuroNCAP does not include a false
activation test because the vehicle could be programmed to pass any
specific false activation test. ASC further stated that the current
sensors used in vehicles do not have the same susceptibility to false
activations that the proposed tests were designed to identify.
Volkswagen and Hyundai questioned whether the test scenarios were
comparable to real world scenarios. MEMA and the Alliance stated that
testing for two specific scenarios does not entirely represent what is
required to design AEB systems that accurately discriminate between
actual crash-imminent situations and false triggers. As a consequence,
the commenters asserted that meeting the proposed performance
requirements only increases testing burdens while not providing a good
indicator of the likelihood of a system producing false activations in
real world driving conditions.
Advocates, Humanetics, and Consumer Reports support the proposed
false activation requirements, stating that to maximize safety and
consumer acceptance, false activations must be limited as much as
possible through test procedures included in the final rule. In
addition, these performance-based tests are a more robust solution than
a document-based approach. Adasky also supported including false
positive testing.
Luminar Technologies stated that it is neutral on the matter of
requiring the false positive testing as proposed or demonstration of
false positive measures by the manufacturer in another way. Luminar
believes that false positive testing is absolutely necessary for safety
and to create public trust, but understands that in some situations,
especially for future autonomous vehicles, that the proposed false
positive scenario may not necessarily occur in the real world.
Porsche recommends NHTSA consider aligning false activation test
requirements with those that are found on the UNECE Regulation No. 152.
Agency Response
The agency has retained the two false activation requirements
including the steel trench plate and the vehicle pass-through
scenarios. Like many NHTSA tests, the false activation tests do not
cover all the situations in the real world where false activations can
occur. However, NHTSA believes that these tests add value to the rule.
The steel trench place test provides protection against a known
engineering challenge for some sensing technologies. Road construction
sites often include steel trench plates for which vehicles will
encounter in the real world. Likewise, a vehicle driven particularly in
urban areas often drives between parked cars on both sides of the road.
Manufacturers must be responsible for false activations regardless
of FMVSS test requirements and must engage in the precision engineering
to prevent false activation and unintended consequences. The industry
responsibility does not mean that NHTSA should not include aspects of
performance that products must continue to meet. NHTSA believes that
issuing an FMVSS with false activation prevent testing underscores the
industry responsibility and works to ensure better performing systems.
The comments from MEMA and Alliance suggests a potential need for
more robust false activation testing. However, it is impossible for
NHTSA to test all circumstances in which false activations may occur.
That is not a logical basis for having no false activation tests. The
commenters did not suggest additional tests for NHTSA to consider in
this final rule.
NHTSA agrees with Advocates, Humanetics, and Consumer Reports that
maximizing safety and consumer acceptance are essential elements to

[[Page 39733]]

help ensure the public receives the benefits of this technology. NHTSA
agrees with Mitsubishi that ultimately protecting against the
activation of AEB in situations where there is no imminent crash is the
responsibility of the manufacturer. However, it is also appropriate for
the FMVSS to set a minimum standard below which no vehicles should
perform. While current systems may be less prone to false activations
in the scenarios proposed, the scenarios represent known
vulnerabilities in previous technologies. The tests ensure that
performance of new technologies continue to provide the resistance to
these false activation situations.
Considering Porsche's suggestion that NHTSA use the same false
activation tests as the UNECE, NHTSA agrees that the curved road and
turning scenarios that are part of UNECE Regulation No. 152 are
relevant real-world conditions. Not all situations, however, can be
tested through regulation. NHTSA is finalizing the two false activation
tests it proposed because of the expected positive impacts they will
have on system performance by preventing reemergence of prior
performance issues and preventing other types of false activations.
2. Peak Additional Deceleration
NHTSA proposed that the AEB system must not engage the brakes to
create a peak deceleration of more than 0.25g additional deceleration
than any manual brake application generates (if used) in the steel
trench plate false activation scenario. Similarly, NHTSA proposed that
the AEB must not engage the brakes to create a peak deceleration of
more than 0.25g beyond any manual braking in the pass-through test.
Comments
Consumer Reports suggested the threshold for maximum deceleration
should be zero, especially under manual brake application. Consumer
Reports opined that a 0.25g braking event is noticeable by passengers
and could confuse or distract the driver. Consumer Reports asked that
NHTSA remove any tolerance for false braking in these scenarios, or at
the very least lower the threshold.
Agency Response
NHTSA is finalizing the braking criteria limit of 0.25g beyond
manual braking as proposed. The agency balanced two factors in
determining that a 0.25g criterion is more appropriate than using a
0.0g criterion. First, the ability to measure negative acceleration
that results from the automatic application of the service brakes is
difficult at low levels. As the total magnitude of deceleration
increases, it is easier to establish that the service brakes are
contributing as opposed to wind, tire friction, or engine drag. Second,
it is unlikely that small levels of additional deceleration (less than
0.25g) could present a safety risk that could potentially lead to a
crash.
3. Process Standard Documentation as Alternative to False Activation
Requirements
As an alternative to the false activation requirements that were
proposed, NHTSA requested comment on requiring manufacturers to
maintain documentation demonstrating that robust process standards were
followed specific to the consideration and suppression of false
application of AEB in the real world. ISO 26262, ``Road vehicles--
Functional safety,'' ISO 21448, ``Safety of the Intended Functionality
(SOTIF),'' and related standards, are examples of this approach. The
agency requested public comment on all aspects of requiring
manufacturers to maintain documentation that they have followed
industry process standards in the consideration of the real-world false
activation performance of the AEB system.
Comments
Advocates, Mitsubishi, the Alliance for Automotive Innovation,
Honda, and FCA opposed the agency's alternative to require that
manufacturers maintain technical documentation that they have followed
industry process standards. Advocates and Consumer Reports stated that
documentation should not be used as a replacement for testing, but as a
supplement to testing. MEMA, ZF and Volkswagen supported the technical
documentation option presented in the NPRM.
Mitsubishi explained as part of its opposition to technical
documentation that it is impossible to predict all false-positive
scenarios and be able to generate technical documentation for it. The
Alliance stated such a requirement will increase the administrative
burden on manufacturers with no added safety benefit. FCA and
Mitsubishi stated that the suggested processes standard, like ISO 26262
or SOTIF, should not be an element of any FMVSS. FCA also stated that
any FMVSS should be purely about a vehicle presented to a test site and
with performance assessed according to objective criteria. FCA further
stated that it is not necessary for the agency to understand how a
product was developed to meet a minimum performance requirement, just
that it does. Finally, FCA noted that NHTSA has other information
gathering powers over industry (e.g., the current ADAS Standing General
Order) and development practices or engineering methods should fall
under that authority, not as part of an FMVSS.
In its support for a technical documentation requirement, ZF stated
that, although they do not recommend a false activation test, they
agree that efforts should be made in system design to mitigate against
that risk. ZF supported some documentation to demonstrate efforts had
been made in system design to prevent false activation. Volkswagen
stated the most effective way to combat false positives is during the
development process. Volkswagen and ZF both considered the suggested
documentation requirements on measures taken against false positives to
be a suitable approach.
Agency Response
After considering comments, NHTSA has opted not to include a
requirement in the FMVSS that manufacturers maintain documentation of
the application of process standards during AEB system development.
Instead, the agency chooses to keep the false activation tests proposed
and incorporate them into this final rule. NHTSA believes that
performance testing of final products remains an important compliance
tool for the agency.
Even though the agency is not finalizing the documentation
proposal, NHTSA disagrees with commenters who asserted that this sort
of documentation is not of use to the agency. The agency believes that
the application of process standards in good faith is likely to
increase the chances that manufacturers have created products that
minimize unreasonable safety risks. NHTSA agrees that the agency has
other pathways through which it could seek this sort of information,
including during an inquiry into the reasonableness of a manufacturer's
certification and through a defect investigation. Therefore, it is not
necessary to include such a requirement in the FMVSS.
4. Data Storage Requirement as Alternative to False Activation
Requirements
As another alternative to the two proposed false activation tests,
NHTSA requested comment on requiring targeted data recording and
storage of significant AEB activations. As an example, NHTSA considered
requiring that an AEB event that results in a speed

[[Page 39734]]

reduction of greater than 20 km/h (12 mph) activate the recording and
storage of key information.
Comments
ASC, IIHS, MEMA, APCI, NTSB, and Forensic Rock supported data
storage requirements. Advocates and Consumer Reports stated data
storage requirements should not be used as a replacement for testing,
but as a supplement to testing. ZF recommended that AEB system data be
retained in some capacity by EDR systems. They stated that
classification of the target that triggered the AEB activation may be
useful for accident or false activation reconstruction. AAA and Rivian
recommended the agency weigh how the data recording requirement would
be implemented in the context of consumer privacy concerns. ASC stated
its support of Event Data Recording (EDR) to assist in crash
reconstruction and identification of false activation trigger factors.
NTSB stated that without the data, it will be extremely challenging to
determine whether and to what extent these systems were engaged during
a crash. Forensic Rock stated that ensuring investigators have access
to post-collision data that can objectively evaluate the performance of
the AEB system in both lead vehicle and pedestrian collision scenarios
is paramount and should be included in the FMVSS.
Honda, Bosch, Hyundai, Mitsubishi, the Alliance for Automotive
Innovation and Volkswagen opposed requirements that would include AEB
data storage. Honda stated that it was unclear as to the problem such a
requirement would be meant to address. Bosch stated data recorders have
limitations and are not able to determine whether a safety system's
decision was reasonable, considering the provided sensor data. Hyundai
stated it would entail significant burdens and unwarranted delays to
this rulemaking and would provide no direct safety benefit. Mitsubishi
stated a lack of objective and clear definitions of false activation
indefinitely increases the data elements to record, which would require
hardware reengineering. In addition, Mitsubishi stated that data is
more likely to include privacy-sensitive information. The Alliance
stated the agency has not provided any analysis on the technical
feasibility of the proposal under consideration, nor has sufficient
justification been made as to the practical utility of any data
obtained as part of an information collection effort or the overall
safety benefit to consumers. Volkswagen stated that to determine
whether an activation was justified, camera data would be required in
most cases and that storing camera data is not technically feasible for
most current vehicle platforms due to processing and storage
limitations of the existing architectures.
Agency Response
After considering comments, NHTSA is not including data storage as
part of this FMVSS, and intends to keep the false activation tests that
it proposed. NHTSA believes that the false activation tests will
provide the minimum level of assurance that AEB systems will not
provide unwarranted engagement. In the future, NHTSA can consider
amending the EDR requirements established in 49 CFR part 563 and more
broadly consider updates to vehicle data collection, event triggers for
crash reconstruction, and potential gaps in performance of AEB and
other safety systems. By looking at vehicle data holistically and
considering the updates necessary to modernize 49 CFR part 563 and
capture the information necessary for various driver assistance
systems, the agency can further consider the data needs and associated
burden to update the regulation to reflect the vehicle safety needs of
today, current vehicle systems, and current manufacturer practices,
while balancing privacy concerns.\104\ Finally, regarding data
manufacturers are already collecting, NHTSA has broad authority to
request information from manufacturers during the course of
investigations. Therefore, even absent a data recording requirement in
an FMVSS or regulation, NHTSA expects that it can require manufacturers
to provide the information that they are currently collecting on AEB
systems.
---------------------------------------------------------------------------

\104\ With regard to consumer privacy, those concerns should be
alleviated, at least partially, by the existence and application of
the Driver Privacy Act of 2015, part of the Fixing America's Surface
Transportation Act of 2015. The Driver Privacy Act assigned
ownership of EDR data, as defined in 49 CFR 563.5, as the property
of the owner or lessee of a vehicle. Importantly, it limits the
access of EDR data to specific parties for specific purposes.
---------------------------------------------------------------------------

G. Malfunction Detection Requirement

In the NPRM, NHTSA proposed that AEB systems must continuously
detect system malfunctions. If an AEB system detects a malfunction that
prevents it from performing its required safety function, the vehicle
would illuminate a telltale that identifies (or indicates) the
malfunction condition. The telltale would be required to remain active
as long as the malfunction exists while the vehicle's starting system
is on. NHTSA would consider a malfunction to include any condition in
which the AEB system no longer functions as required by this rule.
NHTSA proposed that the driver must be informed of the malfunction
condition in all instances of component or system failures, sensor
obstructions, or other situations that would prevent a vehicle from
meeting the proposed AEB performance requirements. While NHTSA did not
propose a specific telltale, NHTSA anticipates that the characteristics
of the alert will provide sufficient information to the vehicle
operator to identify it as an AEB malfunction.
1. Need for Requirement
The rationale behind the requirement that AEB systems continuously
detect system malfunctions is that drivers would need to know when AEB
is not functioning because AEB is an important safety system. NHTSA
stated in the NPRM that it was considering minimum requirements for the
malfunction indication to standardize the means by which the
malfunction is communicated to the vehicle operator. Malfunctions of an
AEB system are somewhat different than other malfunctions NHTSA has
considered in the past. While some malfunctions may be similar to other
malfunctions NHTSA has considered in FMVSSs because they require repair
(loose wires, broken sensors, etc.), others are likely to resolve
without any intervention, such as low visibility due to environmental
conditions or blockages due to build-up of snow, ice, or loose debris.
Comments
Advocates, NAMIC, IIHS, MEMA and NTSB supported the proposed
requirements for malfunction. NAMIC commented that it is important to
include in a final rule a requirement that manufacturers notify the
driver when AEB or other advanced driver assistance systems are
malfunctioning or not performing as designed, and to include detailed
directions for resolving the issue such as cleaning the sensor or going
to a service center.
The Alliance stated that wording of the proposed malfunction
requirements would likely result in excessive notifications to
consumers and notifications that do not accurately communicate the
status of the system. and may be misleading as to the actions required
on the part of the driver to remedy the situation. The Alliance and
Aptiv stated that it is not reasonable or practicable to require a
manufacturer to detect changes in the roadway environment (e.g., road
surface condition) or the extent to which these changes may affect the
performance of a vehicle in meeting the requirements of the rule. The
Alliance, Consumer Reports, and ITS America commented

[[Page 39735]]

that malfunction failure indication should be limited to specific
failures related to the hardware or software components that comprise
an AEB system, not diminished performance due to environmental
conditions such as heavy fog or snow.
The Alliance, NADA, and AAA recommended that NHTSA create separate
definitions for ``malfunction warning'' and ``system availability
warning'' to characterize these two conditions more accurately. Aptiv,
Volkswagen, and Porsche suggested a warning based on UNECE Regulation
No. 152 for non-electrical failures (for example, obstructions due to
weather). Bosch suggested further specification in the warning of ``an
appreciable time interval between each AEB system self-check.''
NTEA recommended that a compromised system function should not only
warn the driver, but consider the possible prohibition of AEB
activation. NTEA also provided cases where they feel sensors need self-
monitoring abilities and temporary deactivation, such as a when going
through a car wash or when overhead cargo is present that obstructs a
portion of the forward camera's field of view.
Agency Response
The agency agrees with commenters who state that it is necessary
that AEB systems monitor system health and notify the driver when a
malfunction is present. Where the agency diverges from commenters is
with regard to the need to require manufacturers to provide detailed
information regarding the nature of the malfunction. The primary
information necessary for a driver to determine if it is safe to
operate the vehicle is simply whether the AEB system is working
relative to the performance requirements of this new final rule.
The agency agrees with the commenters who stated that external
conditions that limit system performance (such as minute changes in the
road surface construction, the presence of sand or gravel on the road
surface, etc.) are not malfunctions of the system, and in some cases,
it is not possible to determine the AEB system's ability to perform.
These conditions are often not readily measurable by vehicle sensors
and are often temporary in nature.
NHTSA is clarifying that it did not intend to mandate that AEB
perform in all environmental conditions. Rather, NHTSA requires that
AEB systems function as required within the set of conditions provided
in S6 of the regulatory text. The same is true for malfunction
detection. NHTSA understands that there are differences between the
driving environment hindering ideal AEB performance and true
malfunctions of the system that likely require intervention to resolve.
To give an example, snow might cause degraded performance for a variety
of reasons, but a malfunction notification would not be necessary
unless that snow results in deactivation of the AEB system, such as a
situation when the snow obstructs the AEB sensors, causing the system
to not meet the performance requirements. Alerting the driver to this
type of malfunction is vital to the safe operation of the vehicle. Any
notification of degraded system performance arising from any source
(temporary or permanent) should end when the conditions that lead to
the degradation end.
Therefore, this final rule clarifies that if the system detects a
malfunction, or if the system adjusts its performance such that it will
not meet the performance requirements, the system must provide the
vehicle operator with a telltale notification. This requirement makes
clear that if the system reduces its performance capabilities
(regardless of if the reason is because of environmental conditions or
for other reasons), the driver must be informed. Also, if the system is
broken or a sensor is obstructed, the driver must be informed. However,
if there are environmental conditions that decrease the system's
ability to function (for instance decreased stopping distance) but the
system has made no internal adjustments, a telltale is not required.
As for the issue of separate telltales to inform the driver of
permanent and temporary malfunctions, the requirement proposed and
adopted here was intended to give manufacturers flexibility in the
style and nature of the driver malfunction notification. The
requirements allow for different notification types for different types
of degraded performance (e.g., internal malfunctions or external
conditions) that degrade performance, should the manufacturer choose to
do so. The manufacturer may also, at the manufacturer's discretion,
choose to use the same telltale or other notification for the different
types of degraded performance. NHTSA has observed that some
manufacturers currently do this and nothing in the NPRM was intended to
prohibit this. This is consistent with the malfunction warning
requirements in UNECE Regulation No. 152.
The agency appreciates Bosch suggesting a more specific definition,
but NHTSA is not adopting the proposed definition for malfunction
detection provided at this time because it is not workable for an
FMVSS. For example, ``appreciable time interval'' is not an objective
measure of timing, nor does it give manufacturers notice as to what
NHTSA expects of them. Furthermore, NHTSA does not have a basis for why
it would treat electrical failure conditions differently than any other
type of system malfunction, as suggested by Bosch.
Regarding NTEA's suggestion that NHTSA prohibit AEB activation in
the instances where a malfunction may be present, NHTSA does not
believe that mandating the prohibition of AEB activation is necessary
since there is no evidence that a manufacturer would permit its systems
to function in a state so degraded as to present an unreasonable risk
to safety.
2. Malfunction Telltale
NHTSA did not propose the specifics of the telltale but anticipated
that the characteristics of the alert would provide sufficient
information to the vehicle operator to identify it as an AEB
malfunction, and would also be documented in the vehicle owner's
manual. NHTSA requested comment on the potential advantages of
specifying test procedures that would describe how the agency would
test a malfunction telltale and on the related level of detail that
this regulation should require. The agency also requested comment on
the need and potential safety benefits of requiring a standardized
appearance for the malfunction telltale and what standardized
characteristics would achieve the best safety outcomes. The agency
further requested comment on the use of an amber FCW warning symbol as
the malfunction notification.
Comments
The Alliance and Nissan commented that specifics of a telltale for
malfunction (and related system status) should be defined by the
manufacturer. Nissan observed that UNECE Regulation No. 152 does not
define the specific form of the malfunction telltale.
ASC suggested that the agency require an AEB malfunction telltale
to be located on the vehicle's instrument panel. ASC stated that on
start-up, the AEB system could run diagnostics and trigger the
malfunction telltale if a failure or obstruction is detected.
However, several other commenters suggested standardization of a
common malfunction telltale. ZF and MEMA suggest a telltale modeled
after the ESC telltale, in an effort to better alert the driver to an
AEB malfunction.
Toyota stated that an amber telltale may be appropriate, as it
aligns with

[[Page 39736]]

similar malfunction requirements, such as those in FMVSS No. 135.
IIHS commented that NHTSA should require manufacturers to notify
the driver when AEB or other ADAS are malfunctioning or not performing
as designed. They noted that, ideally, the notification should provide
directions for resolving the issue, such as cleaning the sensor or
going to a service center, noting that drivers should not be expected
to troubleshoot misbehavior or malfunctions from their ADAS, especially
when the malfunction introduces new risks. They provided two examples
of a vehicle with a misaligned radar following a crash and a skewed
camera following a windshield replacement, which did not provide an
indication of malfunction or reduction of performance.
AVIA commented that for AVs, NHTSA should consider adding language
that allows a malfunction detection notification to be directly
communicated to the ADS itself or communicated to a remote assistant or
to service personnel in the case of an AV without manually operated
driving controls. They added that for an ADS-equipped vehicle with
manually operated driving controls, the notification can be directly
communicated to the ADS when it is engaged as well as through a
telltale notification to the human operator. Zoox commented that the
malfunction telltale requirement should specify that it be visible from
the driver seating position and that, for vehicles without a driver
seating position, the mechanism is specified by the manufacturer and
provided upon request, and suggested that testing not be conducted
while an equivalent notification to the telltale is active for vehicles
without a driver seating position.
Agency Response
NHTSA agrees that the specifics of a telltale for malfunction
should be defined in detail by the manufacturer. The agency has
concerns, however, about drivers confusing a malfunction indicator that
is co-located with the FCW symbol. As such, Toyota's suggestion to
align the malfunction telltale with the FCW symbol may be problematic.
The agency is concerned about confusing drivers, because using the same
telltale could be interpreted as asking the driver to brake or as a
malfunction.
NHTSA understands the positions of commenters who requested a
standardized malfunction telltale. Nothing prohibits the industry from
working together, such as through a standards organization, to
implement a common telltale. However, NHTSA does not believe
standardization is necessary at this time. Commenters did not provide
sufficient evidence to demonstrate a need for a standardized
malfunction indicator. Thus, NHTSA is not adding additional constraints
on the telltale, in this final rule. If warranted, NHTSA would consider
standardization if in the future it is determined that drivers do not
adequately comprehend when an AEB malfunction has occurred.
NHTSA does not agree with ASC's suggestion of a standardized
location for a telltale. FMVSS No. 101 does not provide specification
for the location of any telltale except that it be visible to the
driver when a driver is restrained by a seat belt. There is no evidence
of a safety need for any more specific location requirement for an AEB
system malfunction telltale.
As discussed in other sections, NHTSA agrees with IIHS that the
driver should be notified when AEB is malfunctioning, which is the
entire goal of a malfunction telltale requirement. NHTSA does not
believe that it is necessary to notify drivers of the directions for
resolving the issue, but that such information could be provided to
drivers in the owner's manual. A driver who is driving on the street
doesn't need to be told while the vehicle is moving that she needs to
clean the sensor. Rather, this is diagnostic information that could be
communicated through other means, like through the use of diagnostic
tools accessing information in the OBD-II port.
As for the comments related to AVs, NHTSA believes it is most
appropriate to address specific concerns related to AVs through other
mechanisms, rather than shaping this particular FMVSS around the needs
of a very specific set of vehicles that may still have to apply for an
exemption from other FMVSS. NHTSA is considering crash avoidance test
procedures to facilitate the safe introduction and certification of new
vehicle designs equipped with automated driving systems in a separate
rulemaking.\105\ NHTSA is also looking across all FMVSS to address the
applicability and appropriateness of safety messaging (telltales,
indicators, and warnings) in new vehicle designs without conventional
driver controls.\106\ Additionally, NHTSA notes that manufacturers are
free to design their vehicles to have the malfunction detection
notification be communicated directly to the ADS, a remote assistant or
service personnel, as a redundant means of communication. Such
redundancy is permissible in situations that a manufacturer believes it
is necessary.
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\105\ https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202310&RIN=2127-AM00.
\106\ https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202310&RIN=2127-AM07.
---------------------------------------------------------------------------

3. Sensor obstructions and testing
NHTSA proposed that the driver must be warned in all instances of
malfunctions, including malfunctions caused solely by sensor
obstructions. The NPRM also proposed that during track testing of the
AEB system all sensors used by the system and any part of the vehicle
immediately ahead of the sensors, such as plastic trim, the windshield,
etc., would be free of debris or obstructions. NHTSA stated that it was
considering requirements pertaining to specific failures and including
an accompanying test procedure.
Comments
The Alliance stated that it is important that NHTSA define a finite
set of scenarios that could be reasonably defined as a malfunction,
should the agency decide to regulate in this area, to ensure that
relevant scenarios are being addressed, and that other factors that may
influence AEB performance are evaluated independently. Mobileye
recommended performing full blockage camera/radar testing as in the
Euro-NCAP Assisted Driving protocol. ZF also suggested testing by
obstructing sensors. Rivian recommended that NHTSA adopt detailed
procedures that can be performed on the test track and are
representative of relatively high frequency occurrence in actual use
cases. ZF commented that malfunction indicator light testing could be
done by deliberately blocking for radar to simulate snow accumulation,
or a piece of tape for cameras to simulate a lens blockage.
Agency Response
After considering the comments, NHTSA is not making any further
specifications of failures that would be tested. As is customary with
NHTSA's standards, the laboratory compliance test procedures will
specify how NHTSA intends to run its compliance test regarding
illumination of a malfunction telltale.

H. Procedure for Testing Lead Vehicle AEB

This section describes the lead vehicle AEB performance tests
adopted by this final rule. After considering the comments to the NPRM,
NHTSA has adopted the proposed procedures with a few changes. Some
minor parameters

[[Page 39737]]

and definitions were modified and various definitions were added, to
clarify details of the test procedures. Additionally, to increase the
practicability of running the tests, a third manual brake application
controller option, a force only feedback controller, has been added.
The force feedback controller is substantially similar to the hybrid
controller with the commanded brake pedal position omitted, leaving
only the commanded brake pedal force application.
This section responds to the comments and explains NHTSA's reasons
for adopting the provisions set forth in this final rule. For the
convenience of readers, a list of the test specifications can be found
in the appendix A to this final rule preamble.
The lead vehicle AEB performance tests require a vehicle to
automatically brake, or supplement insufficient manual braking, when
tested during daylight under three specific test scenarios. The
scenarios involve a stopped lead vehicle, a slower-moving lead vehicle,
and a decelerating lead vehicle. The performance criterion for all AEB
tests involving a lead vehicle is full collision avoidance, meaning the
subject vehicle must not contact the lead vehicle.
The lead vehicle AEB tests include parameters necessary to fully
define the initial test conditions in each scenario. Key test
parameters for the lead vehicle AEB tests include the travel speed of
both the subject vehicle and lead vehicle, the initial headway between
the subject vehicle and the lead vehicle, the deceleration of the lead
vehicle, and any manual brake application made to the subject vehicle.
For each test run conducted under each of the scenarios, NHTSA will
select the subject vehicle speed (VSV), lead vehicle speed
(VLV), headway, and lead vehicle deceleration from the
ranges specified in the standard.\107\
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\107\ In instances where an FMVSS includes a range of values for
testing or performance requirements, 49 CFR 571.4 states that the
word any, used in connection with a range of values, means generally
the totality of the items or values, any one of which may be
selected by NHTSA for testing, except where clearly specified
otherwise.
---------------------------------------------------------------------------

There will be testing under two conditions. In one condition, NHTSA
will test without any manual brake application. This would simulate a
scenario where a driver does not intervene at all in response to the
FCW or impending collision. In the other condition, NHTSA will test
with manual brake application that will not be sufficient to avoid the
crash. Not only will the second condition ensure that the AEB will
supplement the manual braking when needed, it also provides a way to
ensure that an application of insufficient manual braking will not
suppress automatic braking in circumstances where automatic braking is
initiated before the manual brake application is used.
1. Scenarios
Many commenters suggested including additional scenarios in lead
vehicle AEB testing.\108\ Many commenters urged NHTSA to include lead
vehicle AEB testing in the dark to increase the benefits of the rule.
The Lidar Coalition commented that it supports testing AEB in the
darkest realistic conditions possible. It stated that a test procedure
in dark conditions would evaluate AEB and PAEB technologies in the
real-world scenarios where these systems are most needed because of
diminished visibility. Forensic Rock state that they found differences
in the performance of a specific vehicle's AEB system during the day as
compared to testing under the same conditions at night and that to
comprehensively evaluate the performance of AEB systems, daytime and
nighttime tests should be conducted under the same closing speeds.
Advocates suggested that NHTSA evaluate and present data demonstrating
that the exclusion of testing lead vehicle (vehicle-to-vehicle) AEB
under dark conditions is not limiting the performance level demanded by
the proposed rule nor needlessly jeopardizing safety.
---------------------------------------------------------------------------

\108\ These commenters included Luminar, Forensic Rock, Consumer
Reports, Applied, Rivian, Advocates, Adsky and the Lidar Coalition.
---------------------------------------------------------------------------

In response, NHTSA appreciates the interest in including additional
scenarios to potentially assess AEB systems under a wider range of
potential real-world situations. NHTSA does not, however, include
further tests in this final rule. The decision to include a particular
test scenario depends on various factors, including the safety benefit
resulting from a requirement, the practicability of meeting the
requirement, the practicality and safety of conducting a test, and, in
accordance with E.O. 12866, the likelihood that market forces will
incentivize manufacturers to provide the needed performance absent the
requirement. NHTSA at present does not have sufficient supporting data
to assess the need for, practicability of, or practicalities involved
with adding darkness test scenarios to the lead vehicle AEB tests. This
is in contrast to the PAEB test, which includes darkness test
scenarios.
There is not enough data supporting a finding for a safety need for
a darkness test. The test scenarios of this rule broadly represent real
world situations by sampling the most common types of light vehicle
rear-end crashes. In NHTSA's latest testing described earlier in this
document, the agency observed that vehicle performance during the dark
ambient tests were largely consistent with those produced during the
daylight tests (in the absence of a regulation). The dark- compared to
day-contact results observed for a given test speed were identical or
nearly identical for several of the vehicles tested. Where impacts
occurred, the impact speeds were very similar. Additionally, as
detailed in the safety problem section of this preamble, 51 percent of
rear end crash fatalities occur during daylight, and injury and
property-damage-only rear-end crashes were reported to have happened
overwhelmingly during daylight, at 76 percent for injury rear-end
crashes and 80 percent for property-damage-only rear-end crashes.
Some data indicate that there may not be a technical need for a
darkness test to reap the benefits of lead vehicle AEB in darkness. As
part of this final rule, NHTSA is specifying minimum performance
requirements for pedestrian avoidance in dark conditions. The agency
believes that systems that can identify, and respond to, a pedestrian
in the roadway at night could also possibly detect lead vehicle
taillamps and other reflective surfaces that distinguish a vehicle from
the surrounding visual landscape. The agency also believes a radar
sensor will perform the same regardless of the lighting condition. As
such, NHTSA believes an AEB system could be highly effective at
classifying the rear of a lead vehicle in a dark condition, even
without an explicit regulation requiring such performance. Only the
daylight condition was proposed for lead vehicle AEB testing, and this
sole lighting condition is maintained in this final rule.
Luminar, Forensic Rock, Consumer Reports, and Aptiv suggest the
agency expand testing with additional overlaps (the measurement of
deviation of the lead vehicle centerline and the subject vehicle
centerline) for lead vehicle testing. Luminar stated that a 50 percent
overlap in car-to-car scenario is used in both US and Euro NCAP testing
and suggested that NHTSA should consider 50 percent overlap which, the
commenter believed, is a common, achievable, car-to-car test scenario.
Forensic Rock suggests expanding the testing to include a 25-50%
overlap condition would ensure that the

[[Page 39738]]

performance of these systems included more than just pure collinear
crash scenarios.
In response, NHTSA has not included test scenarios with an overlap
less than 100 percent (although a tolerance on the travel path of the
subject vehicle is included). A rear-end crash as defined in the FARS
database is ``a collision in which one vehicle collides with the rear
of another vehicle.'' \109\ Even at the higher speeds used in testing,
a change of the overlap during testing from 100 percent to 50 percent
or 25 percent would result in only a marginal change in the position of
the lead vehicle in the field of view of the sensors. The proposed
overlap for lead vehicle AEB testing is consistent with NHTSA's NCAP
test procedures for CIB and DBS, the IIHS test procedure, as well as
UNECE Regulation No. 152.\110\ The agency does not have the necessary
information to demonstrate practicality and need for a regulation that
adopts scenarios that include a broad range of overlap.
---------------------------------------------------------------------------

\109\ https://www-fars.nhtsa.dot.gov/Help/
Terms.aspx#:~:text=Rear%2Dend%20Collision,The%20Rear%20Of%20Another%2
0Vehicle. Accessed November 21st, 2023 at 3:22 p.m.
\110\ National Highway Traffic Safety Administration (Oct.,
2015), Crash Imminent Brake System Performance Evaluation for The
New Car Assessment Program. Available at: https://www.regulations.gov/document/NHTSA-2015-0006-0025; National Highway
Traffic Safety Administration (Oct., 2015), Dynamic Brake Support
Performance Evaluation Confirmation Test for The New Car Assessment
Program. Available at: https://www.regulations.gov/document/NHTSA-2015-0006-0026; Insurance Institute for Highway Safety (Oct., 2013),
Autonomous Emergency Braking Test Protocol (Version I), Available
at: https://www.iihs.org/media/a582abfb-7691-4805-81aa-16bbdf622992/REo1sA/Ratings/Protocols/current/test_protocol_aeb.pdf; and UN
Regulation No 152--Uniform provisions concerning the approval of
motor vehicles with regard to the Advanced Emergency Braking System
(AEBS) for M1 and N1 vehicles [2020/1597] (OJ L 360 30.10.2020, p.
66, ELI: http://data.europa.eu/eli/reg/2020/1597/oj).
---------------------------------------------------------------------------

Some commenters suggest that NHTSA should consider adding
additional testing scenarios from EuroNCAP, such as the head-on
scenarios and left turn across path. Consumer Reports suggested NHTSA
incorporate additional scenarios such as a curved travel path,
scenarios involving challenges posed by environmental conditions, and
circumstances in which the lead vehicle is revealed suddenly or is not
aligned straight when in front of the subject vehicle.
In response, this final rule requires lead vehicle AEB systems that
will prevent or mitigate rear-end crashes of light vehicles and is
based on the research and other data demonstrating the efficacy and
practicability of these systems. The data and technologies for test
scenarios representing crashes other than a rear-end crash are not yet
available to support possible inclusion in an FMVSS.
Applied stated that NHTSA should include additional scenarios and
elements through virtual testing procedures. It stated that modeling
and simulation technologies allow for a vehicle to be put through a
much more expansive set of testing scenarios and elements than what are
possible in real-world testing and may allow to vastly increase the
number of tests that can be run creating a much greater pool of data to
evaluate a vehicle.
In response, while virtual test scenarios involving modeling and
simulation may be employed, and are employed, by manufacturers in
developing lead vehicle AEB systems, such testing is not suitable for
NHTSA's compliance testing of AEB systems at this time. Virtual testing
has the potential to provide many benefits and advancements to motor
vehicle safety. There are challenges, however, in using virtual
assessments in agency compliance tests. The agency must be assured that
the virtual scenarios it was running are representative of the real
world and that the test results it obtained would be the same as those
obtained in tests of an actual vehicle. Neither condition currently
exists. Also, virtual test environments are reliable only if they have
been appropriately validated. Right now, NHTSA does not have the
research available to support the development of a simulator designed
for the purposes of testing compliance with this rule. Though
simulation testing is a method that NHTSA is very interested in from a
research perspective, it is not yet an approach that is ready for NHTSA
use in compliance testing.\111\
---------------------------------------------------------------------------

\111\ There are also several practical challenges that prevent
NHTSA from using virtual testing to determine compliance with the
FMVSS. NHTSA's goal is to independently purchase vehicles available
on the market without notification to the manufacturer (or anyone)
that it is purchasing a particular vehicle. This helps make sure
that the product that NHTSA is testing is one that consumers of that
product would also purchase. If NHTSA were to obtain vehicles
directly from manufacturers for compliance testing, NHTSA may not be
as confident about the independence of its testing results. Also,
AEB systems are proprietary systems. If NHTSA needs capabilities and
access to the technicalities of the AEB system to conduct virtual
testing, confidential business information issues may arise.
---------------------------------------------------------------------------

After considering the comments, this final rule adopts the three
track test scenarios, which are lead vehicle stopped, lead vehicle
moving and lead vehicle decelerating, as proposed in the NPRM.
2. Subject Vehicle Speed Ranges
The proposed speed ranges were selected based on the speeds at
which rear-end crashes tend to happen, while considering two primary
factors. The first factor is the practical ability of AEB technology to
consistently operate and avoid contact with a lead vehicle. NHTSA's
2020 and 2023 research testing indicate that the selected speed ranges
for the various scenarios are within the capabilities of current
production vehicles. NHTSA proposed speed ranges to ensure AEB system
robustness. To illustrate, during the agency's AEB research testing,
two vehicles performed better at higher speeds (48 km/h or 30 mph) than
at lower speeds (40 km/h or 25 mph) in the lead vehicle stopped tests,
which suggests that a range of speeds should be used in FMVSS No.
127.\112\
---------------------------------------------------------------------------

\112\ https://www.regulations.gov/document/NHTSA-2021-0002-0002.
---------------------------------------------------------------------------

The second factor is the practical limits of safely conducting
track tests of AEB systems. Based on the available data, a majority of
fatalities and injuries from rear-end crashes occur at posted speeds up
to 97 km/h (60 mph). Due to the tendency of fatalities and injuries to
increase as the vehicle travel speed increases, NHTSA proposed AEB
system testing at the highest speeds at which NHTSA can safely and
repeatably conduct tests. If a system does not intervene as required
and the subject vehicle collides with the lead vehicle test device, it
should do so in a manner that will not injure test personnel or
demolish the laboratory's equipment and set-up.
Comments Seeking To Increase Testing Speeds To Increase Potential
Safety Benefits
Many government entities, consumer interest groups, private
individuals and others suggested that NHTSA consider exploring ways to
increase test speeds.\113\ Many suggested lead-vehicle AEB tests above
100 km/h (~60 mph) for the stopped lead vehicle and slower-moving lead
vehicle scenarios, and 80 km/h (~50 mph) for the decelerating lead
vehicle scenarios. These commenters point to the increased risk of
crashes as well as fatalities and serious injuries resulting from
crashes as speeds rise, and some believed that a requirement to meet
higher test speeds is practicable. Forensic Rock stated that if a
private accident reconstruction firm can find suitable track length to
conduct

[[Page 39739]]

high closing speed tests, NHTSA should be able to as well. NTSB stated
that test scenarios be designed to best reflect real world operating
conditions as NTSB investigations have shown there is a need to
consider systems' performance in other crash-relevant scenarios
including unusual vehicle profiles and configurations encountered in
real-world conditions.
---------------------------------------------------------------------------

\113\ These commenters included the cities of Philadelphia,
Nashville, and Houston, the Richmond Ambulance Authority, DRIVE
SMART Virginia, NACTOA, the Lidar Coalition, Consumer Reports,
Forensic Rock, and Luminar.
---------------------------------------------------------------------------

Agency Response
After considering the comments, NHTSA declines to increase the test
speeds proposed in the NPRM. The agency explained in the NPRM that
NHTSA proposed what it believed to be the highest practicable and
reasonable testing speeds. Testing speeds are bound by important
practicability matters and practical limitations, such as the safety of
the testing personnel, vehicle and test equipment damage, and the
repeatability of testing and test validity. Forensic Rock suggested
adding equipment such as ``deer/cattle guards'' to the subject vehicle
during testing. NHTSA believes such an approach is untenable because
such equipment would still not protect testing equipment and would
alter the ``real-world'' condition of the vehicle.
NHTSA limited the maximum test speeds for lead vehicle AEB to no
more than a maximum 80 km/h (50 mph) speed differential. NHTSA is
encouraged by Luminar and Forensic Rock's testing at speeds higher than
the NPRM, but, with regard to Luminar's comment that the systems they
tested performed at speeds up to 120 km/h, the agency's limit for the
testing speed was determined based on factors including safety need and
practicability, and not just on AEB performance. While NHTSA is
currently researching other testing scenarios for AEB, the agency does
not have the needed information regarding practicability and the need
for a higher speed regulation to include a broader speed range at this
time.
Comments Suggesting Different Approaches
Several commenters suggested NHTSA should take a hybrid approach
and reduce speeds for a no-contact requirement while allowing contact
at a higher speed. The Alliance, Toyota and others suggested NHTSA
implement a hybrid approach that maintains no-contact requirements for
lower-mid-range speeds while permitting compliance if acceptable speed
reductions that reduce the risk of serious injury can be achieved in
higher-speed scenarios. It stated that such an approach would align
with the approach implemented by other international bodies, such as
UNECE Regulation No. 152, where no contact is required up to 40 km/h
and various levels of maximum impact speeds are allowed from 42 km/h up
to 60 km/h.\114\ A number of other commenters suggested reducing the
range of testing speeds and allowing contact above certain testing
speeds.\115\
---------------------------------------------------------------------------

\114\ https://unece.org/transport/documents/2023/06/standards/un-regulation-no-152-rev2. Other commenters supported harmonizing
with UNECE Regulation No. 152, including ASC, Ford, Mitsubishi, and
Nissan.
\115\ These commenters included HATCI, Nissan, ZF, and Aptiv.
---------------------------------------------------------------------------

The Alliance stated that the hybrid approach would ensure that
vehicle speeds are reduced to a level where crashworthiness features
can provide an additional layer of protection for reducing the severity
of occupant and pedestrian injury outcomes by lowering the overall
impact speed. Volkswagen provided an analysis, which it stated is not
statistically significant, which showed that vehicles on the road today
can protect their occupants from severe injuries of MAIS 3+ even with
collision speeds up to 50 km/h. Toyota recommended an approach that
vehicle-to-lead vehicle target contact be allowed ``at a speed low
enough that the crash would be highly unlikely to be fatal or to result
in serious injury.'' Honda also considered NHTSA's crash injury
estimations for the risk of severe injury or fatality in frontal
crashes to suggest a hybrid type approach.
Agency Response
The commenters support a hybrid approach where collision avoidance
would be required only up to 42 km/h (26.1 mph) and speed reduction (a
mitigated collision) permitted at speeds above 42 km/h (26.1 mph)
during testing. NHTSA does not find this approach acceptable. The
agency's intent is to prevent crashes at the highest practicable speeds
and the proposed limits in testing speeds reflect this.
Using the speed limit as a proxy for traveling speed, the data
presented earlier in this document show that about 60 percent of fatal
rear-end crashes were on roads with a speed limit of 97 km/h (60 mph)
or lower. That number is 73 percent for injury rear-end crashes and 78
percent for property-damage-only rear-end crashes. Out of the total
rear-end crash population, only about 1 percent of fatalities, 5
percent of injuries and 7 percent of property-damage-only crashes
happen where the speed limit is 40 km/h (25 mph) or less. If NHTSA were
to require collision avoidance only for crashes up to 40 km/h (25 mph),
in NHTSA's view only a fraction of fatalities and injuries would be
avoided when so many more motorists could benefit. Such an outcome
would fall short of meeting the need for safety, as meeting the
proposed test speeds is practicable. As detailed in the research
section, the 2023 Toyota Corolla Hybrid was able to avoid collision
under all testing conditions up to the maximum proposed testing speed
requirement for lead vehicle stopped and lead vehicle moving. That same
vehicle, when tested for the lead vehicle decelerating scenario with a
12 m headway and 0.5g lead vehicle deceleration, was able to avoid
collision in all trials when tested at 50 km/h and was able to avoid
collision on two trials and incur impact speeds of approximately 5 km/h
and below on the other three trials when tested at 80 km/h (50 mph). If
NHTSA were not to require collision avoidance during testing at speeds
up to 100 km/h (62 mph), the majority of fatal rear-end crashes would
not be prevented.
NHTSA is providing a five-year lead time to push development of the
technology while providing time to foster the evolution of it to
achieve AEB's life-saving potential. Four out of the six vehicles
tested avoided collision during agency testing at 50 km/h subject
vehicle to 50 km/h lead vehicle and 12 m and the other two avoided in
four out of the five trials. Considering that current AEB systems seem
somewhat detuned at higher speeds because they were not designed to
this requirement, the agency is encouraged that when engineered to meet
this requirement, AEB will be able to avoid collision in a similar
fashion as they do now under the 50 km/h condition.
The injury curves and thresholds provided by the commenters show
that below 40 km/h (25 mph), there is a reduced probability of AIS3+
injury. With AEB, there is the potential to prevent the crash from
occurring in the first place, i.e., to completely mitigate the risk of
injury. The technology has proven capable of avoiding collisions during
testing at higher speeds. With the potential of AEB technology, its
rapid evolution, and the significant lead time this final rule is
providing to allow for maturation and deployment of AEB, NHTSA has
decided to maintain the no-contact requirement and speed limits at the
levels proposed in the NPRM.
As another approach, Honda suggested to test only at what they
state are worst case scenarios that pose the highest risk of injury
(i.e., impact relative speed) and present the most challenging
situations for AEB systems to react quickly (i.e., time to impact).
Honda stated that after evaluating

[[Page 39740]]

various combinations within the proposed headway distance and lead
vehicle deceleration ranges, the worst-case scenarios are for impact
relative speed of 72 km/h, time to collision (TTC) of 2.1 sec with a
lead vehicle deceleration of 0.5 g, at both the 12 m and 40 m headway
distances at 50 or 80 km/h.
In response, NHTSA does not believe that ``worst case'' scenario
testing is appropriate for this standard in this final rule. In past
NHTSA tests, vehicles sometimes avoided contacting the vehicle test
device at higher speed tests but contacted it at lower speeds. A range
of tests is necessary to better ensure satisfactory performance of the
systems in the real world.
Some Commenters Suggest Reduced Speeds and Repeat Trials To Avoid What
They See as Potential Negative Consequences
A number of commenters believed that having to meet the higher end
of the proposed speed range will increase the likelihood of negative
consequences. Several commenters believed that the higher end of the
proposed speed range will increase the likelihood of false
positives.\116\ Porsche and Volkswagen stated that doubling the
relative velocity at which no contact is required, as compared to UNECE
Regulation No. 152, may impact the robustness of the system in real-
world performance, potentially leading to increased instances of
premature or unnecessary braking in the real-world. Aptiv stated that
due to the possibility of false positives, NHTSA should reduce testing
speeds to 50 km/h (31 mph) and allow repeat trials. Mobileye stated
that the proposed requirement will necessitate hardware updates or
replacement, and preferred a speed reduction requirement, based on a 2
out of 3 test runs. HATCI stated that NHTSA should follow the AEB
voluntary commitment requirements.\117\
---------------------------------------------------------------------------

\116\ These commenters included, ASC, Mobileye, Bosch, Ford,
Mitsubishi, Honda, the Alliance, Porsche, Volkswagen, HATCI, Rivian,
Bosch, and Aptiv.
\117\ The voluntary commitment included automatic braking system
performance (CIB only) able to achieve a specified average speed
reduction over five repeated trials when assessed in a stationary
lead vehicle test conducted at either 19 or 40 km/h (12 or 25 mph).
To satisfy the performance specifications in the voluntary
commitment, a vehicle would need to achieve a speed reduction of at
least 16 km/h (10 mph) in either lead vehicle stopped test, or a
speed reduction of 8 km/h (5 mph) in both tests.
---------------------------------------------------------------------------

Agency Response
One reason the commenters requested lowering the upper speed range
for a no-contact requirement was the concern that false activations
would increase. In the NPRM, NHTSA stated that the proposed testing
requirements are practicable and are intended to avoid and mitigate the
most crashes. In the NPRM, NHTSA expressed that AEB systems are
undergoing rapid advancement and have been able to achieve collision
avoidance at higher testing speeds without major updates. Since the
publication of the NPRM, NHTSA research has confirmed that a vehicle
(the 2023 Toyota Corolla Hybrid) was able to avoid collision under all
testing conditions up to the maximum proposed testing speed requirement
for lead vehicle stopped and lead vehicle moving. That same vehicle,
when tested for the lead vehicle decelerating scenario with a 12 m
headway and 0.5 g lead vehicle deceleration, was able to avoid
collision in all trials when tested at 50 km/h and was able to avoid
collision on two trials and incur impact speeds of approximately 5 km/h
and below on the other three trials when tested at 80 km/h (50 mph).
This vehicle's ability to pass these tests demonstrate that the
proposed requirements are practicable and the technology is still
evolving. As stated in the NPRM, the expectation for the tested AEB
production systems (which were not designed to meet these requirements)
was not that they would pass all trials; rather, it was to inform the
agency on the practicability of the proposed testing speeds. The fact
that a current AEB system is already capable of meeting the AEB
requirements confirms the agency's assumption that current AEB systems
can be further developed within the lead time provided.
Another area of concern expressed by the commenters was sensor
range performance. Honda and Bosch both had concerns about requiring no
contact when testing at higher speeds as current AEB systems sensor
range makes it difficult for the system to discern objects far enough
to achieve no contact and mitigate false positives. In previous agency
testing that informed development of the NPRM, for the vehicle that
performed the best--according to the publicly available information
from the manufacturer--the upgrades to the AEB system from the previous
generation included, among others, improved sensor range.\118\ As shown
by the evolution of the Toyota system, and based on the testing results
from the other vehicles which also show significant advancement in
collision avoidance, NHTSA is confident that current systems, given
sufficient development time, can be engineered to avoid contact and
mitigate false positives in a similar manner as the Toyota system.
---------------------------------------------------------------------------

\118\ https://www.jdpower.com/cars/shopping-guides/what-is-toyota-safety-sense, accessed November 13, 2023.
---------------------------------------------------------------------------

The request for further development time was raised by the majority
of industry commenters, and, as discussed later in this preamble, NHTSA
agrees and is providing more time to meet this final rule. Based on the
comments received, it seems that the main solution currently employed
by manufacturers to mitigate false positives is to detune the system at
higher speeds (consistent with current UNECE requirements). Euro NCAP,
while not a regulation, employs similar testing at similar speeds as
proposed in the NPRM (and adopted by this final rule), and many
vehicles achieve a full score on Euro NCAP testing due to their
collision avoidance capabilities. This information further reinforces
NHTSA's assessment that the proposed testing speeds are practicable and
deployable in the real world with sufficient lead time.
Ford stated that harsh braking to avoid high speed collisions can
result in rear end collisions based on an internal controllability
study with randomly selected drivers in Germany. Based on that study
Ford stated there is an increase in rear end collisions resulting from
AEB activation above differential speeds of 60 km/h (37.5 mph).
In response, NHTSA was unable to find this study as Ford did not
provide any data on it. Thus, NHTSA was unable to evaluate the
relevance of Ford's statement to the current rule. The agency observes,
however, the proposed requirements do not require hasher braking than
currently demonstrated by vehicles compliant with FMVSS No. 135.
Further, if all vehicles were equipped with AEB systems conforming to
this final rule, it is plausible that no crash would happen.
Comments About Increased Costs as New Hardware is Needed
Mobileye stated that for the stopped lead vehicle, the majority of
AEB systems in vehicles today will need a new safety strategy and may
need hardware updates/replacements. Therefore, Mobileye states, the
assumption that all vehicles have the necessary hardware is not
correct.
Agency Response
In response, NHTSA concurs that the cost estimates in the NPRM
underestimated the incremental hardware costs associated with this
final rule. Accordingly, this final rule has

[[Page 39741]]

adjusted the estimates presented in the NPRM to include the costs
associated with software and hardware improvements, compared to the
baseline condition. Incremental costs reflect the difference in costs
associated with all new light vehicles being equipped with AEB with no
performance standard (the baseline condition) relative to all light
vehicles being equipped with AEB that meets the performance
requirements specified in this final rule. The Final Regulatory Impact
Analysis (FRIA) provides a detailed discussion of the benefits and
costs of this final rule.
Comments About the Effect of Test Speed on Evasive Steering
When a driver is alerted to an impending crash, the driver may
manually intervene by, for example, applying the vehicle's brakes or
making an evasive steering maneuver, to avoid or mitigate the crash.
Several commenters believed that the agency should ensure that all
final test conditions (especially at higher test speeds) would preserve
steering intervention or other intentional driving behavior regarding
the TTC intervention times.
A number of commenters believed that at higher testing speeds, AEB
could interfere with evasive steering maneuvers.\119\ Honda stated that
AEB should only intervene when a collision is otherwise unavoidable and
is designed to intervene as late as possible to mitigate injury and not
interfere with evasive or normal driver steering maneuvers. Honda
stated that differentiating between those situations where steering is
more appropriate than emergency braking is critical when considering
the unintended consequences of AEB. Honda believed that, under the
proposed speeds, AEB intervention will be forced to occur before the
driver might steer, hindering the driver's appropriate and intended
response in real-world higher speed scenarios.
---------------------------------------------------------------------------

\119\ These commenters included ASC, Mobileye, Bosch, the
Alliance, HATCI, Ford, Mitsubishi, Porsche and ITS America.
---------------------------------------------------------------------------

The Alliance stated that, based on a NHTSA study,\120\ the time
required to avoid impact by steering or braking are equal at
approximately 35 kph and 0.61 seconds and that above 35 kph, avoidance
though braking begins to require increasingly more time than steering.
Drivers are generally more likely to initiate braking to avoid striking
an object at speeds below 44 kph and are more likely to initiate
steering to avoid impact above 44 kph. The Alliance stated that the
driver will typically initiate their maneuver before 1.7 seconds TTC
and therefore, any ``no-contact'' requirement for AEB at higher speeds
will necessitate activating AEB before the driver has an opportunity to
steer around the threat when a steering maneuver would be more
effective. Similarly, Toyota stated that NHTSA should define a maximum
speed for the lead vehicle AEB testing with no manual brake
application, of no greater than 60 km/h for the ``no-contact''
requirement, due to the potential effect of evasive steering and the
timing of AEB activation.
---------------------------------------------------------------------------

\120\ Forward Collision Warning Requirements Project Final
Report--Task 1 (DOT HS 809 574)--January 2003.
---------------------------------------------------------------------------

Agency Response
NHTSA has considered the comments but does not find the arguments
relating to evasive steering compelling. AEB intervention is a last
resort crash avoidance maneuver, and it does not seem reasonable to
assume that a driver who is inattentive until moments before a crash
will reengage and be able to perform a safe steering maneuver that
would not jeopardize other traffic participants. The information
provided by Honda, Toyota, and the Alliance seem to consider only the
timing required for a vehicle to brake to a complete stop versus the
timing of a steering maneuver, without considering any other factors.
Such factors as vehicle dynamics, traffic conditions, and traffic
participants all influence the safety benefit of a steering avoidance
maneuver. While NHTSA does not encourage aggressive and unsafe driving
behavior as shown in that example, we do note that because the test
procedures involve manual braking, disengagement of AEB cannot happen
solely due to brake application. Nothing in our standard, however,
requires a manufacturer to suppress steering. A manufacturer, outside
of the testing requirements, may elect to detune or disengage the AEB
system based on an emergency steering maneuver as long as they meet all
the AEB requirements.
The type of roadway (two lane, divided, interstate) is an important
factor in assessing whether a steering maneuver is appropriate, as is
the traffic on such roadways. It seems unreasonable to expect that,
except for very specific situations such as when an adjacent lane
exists and is empty, a disengaged driver could perform any type of
steering maneuver safer than stopping in the lane.
In normal driving situations, rear end crashes frequently happen in
heavy traffic where crash avoidance maneuvers from automatic or manual
steering could cause the vehicle to either depart the road, collide
with a vehicle in the adjacent lane, or, on an undivided two-lane road,
cause a head-on frontal crash. Further, research referenced by Porsche
in their comments shows that overwhelmingly, drivers either brake, or
brake and steer, when presented with a surprise obstacle catapulted
from the side.\121\ In this research, when the obstacle was presented
to the drivers at a TTC of 1.5s, with the adjacent lane free of
obstacles and the drivers had the opportunity to avoid a collision by
steering alone, 43 percent of participants attempted to avoid by
braking alone. The other 57 percent of participants tried to avoid the
collision by braking and steering, while no participant tried to avoid
contact by steering alone.
---------------------------------------------------------------------------

\121\ Emergency Steer and Brake Assist--A Systematic Approach
for System Integration of Two Complementary Driver Assistance
Systems (Eckert, Continental AG, Paper Number 11-0111), https://www-esv.nhtsa.dot.gov/Proceedings/22/files/22ESV-000111.pdf.
---------------------------------------------------------------------------

At a TTC of 2.0 s, 46 percent of participants tried to avoid by
braking alone, 38 percent by braking and steering, and 15 percent by
steering alone, while at a TTC of 2.5s 72 percent of participants tried
to avoid by braking only, 14 percent tried to avoid by braking and
steering, and 14 percent tried to avoid by steering alone.
This research found that only at TTCs later than two seconds did
drivers attempt to avoid only by steering alone, which suggests that
drivers were not comfortable steering to avoid the presented object at
the speed they were traveling without braking, further reinforcing the
agency's assertion that braking in lane is appropriate. Looking at
these results and considering that this research was performed with a
surprise object catapulted from the side (which induces a preference
for drivers to avoid by steering), it is clear that drivers are more
inclined to brake in an emergency. Additionally, drivers brake even as
they attempt a steering maneuver, which can lead to unstable vehicle
dynamics. This serves to reinforce the agency's findings that a brake
in the lane maneuver, even if it occurs early, before a TTC of 1.5s, is
the safest, most appropriate, maneuver.
The other situation where steering may be more appropriate,
according to the commenters, is an engaged driver who consciously
decides to avoid by steering. The steering avoidance maneuver by an
engaged driver as shown by HATCI in their comment would still present a
higher safety risk than a brake in the lane maneuver. In that example,
a vehicle avoids the lead vehicle by cutting in front of a vehicle

[[Page 39742]]

on the adjacent lane. NHTSA fails to understand how such a maneuver is
safe for any of the vehicles involved, especially considering the
likelihood that other vehicles would be in the adjacent lanes. A
subject vehicle darting out of its lane into an adjacent lane could
result in a different type of crash.
3. Headway
Comments
A key test parameter for the lead vehicle AEB tests is the initial
headway \122\ between the subject vehicle and the lead vehicle. Several
vehicle and equipment manufacturers opposed the proposed headway
conditions (12 m at 80 km/h) in decelerating lead vehicle AEB
tests.\123\ They stated that the proposed headway requirement is not
practical because the short headway values at high relative speeds go
beyond the capabilities of current AEB systems. Volkswagen, Porsche,
Rivian, and others argued that the low headway conditions at high
relative speeds may increase false positive rates, leading to phantom
braking because earlier braking means the system looks further ahead,
both in space and in time. (Hence, commenters stated, the probability
for a collision is estimated at a lower accuracy value and this may
lead to a false positive activation.)
---------------------------------------------------------------------------

\122\ Headway refers to the distance or interval of time between
vehicles moving in the same direction on the same route.
\123\ These commenters included Volkswagen, Porsche, Mitsubishi,
Rivian, Honda, MEMA, Bosch, and Mobileye.
---------------------------------------------------------------------------

Many commenters believed the 12 m proposed headway at 80 km/h is a
very close following distance that would equate to an unsafe following
distance in the real world and that AEB systems are not designed to
account for this type of ``misuse'' by the driver. In addition, they
believed that compliance with a no-contact requirement would require
immediate emergency braking at maximum deceleration, which, the
commenters stated, would result in an uncontrollable safety hazard for
following traffic. Volkswagen and Porsche suggested removing the 12 m
headway at the 80 km/h scenario from the decelerating lead vehicle
tests and aligning with the requirements of UNECE Regulation No.
152.\124\ Similarly, Mitsubishi suggested 23 m as the minimum headway
because the proposed minimum headway distance (12 m) is considered
close enough to issue an FCW even with minimal deceleration of the
subject vehicle. MEMA and Bosch suggested a headway greater than 16 m
and a time gap greater than 0.2 seconds at 80 km/h to create a more
representative test scenario that resembles a constant following
distance. Mobileye stated that the headway of the 12 m in decelerating
lead vehicle test scenario at 80 km/h is around 0.5 s which, the
commenter believed, was not realistic because research data showed that
the median headway time across 10 different sites was 1.74 s.
---------------------------------------------------------------------------

\124\ That regulation currently requires full collision
avoidance up to 40 km/h relative speed between the subject and lead
vehicle.
---------------------------------------------------------------------------

Agency Response
The agency disagrees with Volkswagen and other manufacturers that
the lower bound (i.e., 12 m) of the headway range is not practicable
for the current AEB systems at a high speed (e.g., 80 km/h). NHTSA
discussed in the NPRM that 4 out of 11 vehicles in the agency's 2020
AEB research met the no-contact requirement of this rule when the
subject vehicle and lead vehicle were traveling at 72.4 km/h (45 mph)
with an initial headway of 13.8 m (45 ft). The deceleration of the lead
vehicle was 0.3 g. This research also included decelerating lead
vehicle testing at 56.3 km/h (35 mph) with a deceleration rate of 0.5
g.
In the NPRM, NHTSA tentatively concluded that the current lead
vehicle AEB systems would be able to meet the most stringent headway
requirement (i.e., 12 m) if their perception software was properly
tuned for the higher lead vehicle deceleration (0.5 g). The agency's MY
2023 AEB research supports this.\125\ The test results demonstrated
that one of the six vehicles was able to meet the requirements of this
standard in all five trials at 80 km/h with the initial headway of 12 m
and the lead vehicle deceleration of 0.5 g. Another vehicle was also
able to meet the test requirements in 2 out of 5 trials for the same
test speeds.
---------------------------------------------------------------------------

\125\ NHTSA's 2023 Light Vehicle Automatic Emergency Braking
Research Test Summary, available in the docket for this final rule
(NHTSA-2023-0021).
---------------------------------------------------------------------------

In their comment, Honda stated that the worst-case scenarios for
impact relative speed (72 km/h) are accomplished with a lead vehicle
deceleration of 0.5 g at the 12 m headway distance. Given the
performance of these two vehicles in the most difficult testing
scenario, NHTSA continues to believe that the headway specifications of
this final rule--any distance between 12 m (39.4 ft) and 40 m (131.2
ft)--are within the capabilities of the AEB systems designed to comply
with this final rule.
As for the potential increase of false positive rate raised by
Volkswagen, Porsche and Rivian, false positive activation that causes
an unreasonable risk to safety is a defect issue. Vehicle manufacturers
are responsible for mitigating and resolving any defects in their
vehicle products. Here, the concern is based on a hypothetical
situation where a vehicle at a high speed with a small headway (e.g.,
12 m) may prematurely activate the AEB system--forcing initiation of
early braking--when there is not a true risk of an imminent collision.
At 80 km/h (50 mph), a headway of 12 m is uncomfortably close to a
crash imminent situation and the agency feels strongly that it is
difficult even for an attentive driver to react properly to avoid a
crash in this scenario, especially with a lead vehicle braking above
0.3g. It is up to manufacturers to design their AEB systems to deal
with situations where the driver is following close to the vehicle in
front of it, and the lead vehicle decelerates between 0 and 0.3 g. They
must determine what is a false positive and what is an actual positive.
As for replacing the current range requirements for headway with
discrete values, NHTSA disagrees with Honda and Volkswagen that the
range requirements require infinite number tests and cause unreasonable
test burden to manufacturers. The agency noted in the NPRM that the use
of a range of potential values allows NHTSA to ensure that AEB system
performance remains consistent, as conditions--in this case headway--
vary within the bounds of the range. NHTSA has observed that some lead
vehicle AEB systems performed well under high speed or shorter headway
scenarios, but did not perform as well under lower speed or longer
headway scenarios. This type of performance inconsistency is why the
agency proposed a range of values, and not just discrete values.
The current range headway provides manufacturers an understanding
of the performance the FMVSS requires. Manufacturers have the ability
and flexibility to decide how they can certify that a given AEB system
complies with the requirements contained in this final rule. This
includes the number and types of tests needed to ensure that an AEB
system works throughout the proposed range. The agency is providing
notice of how we test a vehicle's compliance. For these reasons, NHTSA
believes that the headway range requirements do not cause an
unreasonable test burden.
Accordingly, NHTSA declines to amend the range of headway
specifications in decelerating lead vehicle AEB tests. This final rule
adopts that the headway specifications in

[[Page 39743]]

decelerating lead vehicle AEB tests to include any distance between 12
m (39.4 ft) and 40 m (131.2 ft) as proposed in the NPRM.
4. Lead Vehicle Deceleration
The decelerating lead vehicle scenario is meant to assess the AEB
performance when the subject vehicle and lead vehicle initially are
travelling at the same constant speed in a straight path and the lead
vehicle begins to decelerate. NHTSA's proposed lead vehicle AEB tests
included parameters for the deceleration of the lead vehicle.
Honda expressed concern that the proposed rule included a broad
range of parameters for lead vehicle deceleration (ranging from 0.3 to
0.5 g). It further stated that testing a theoretically infinite number
of combinations within the proposed range is impractical. Honda
suggested that the proposed range of deceleration values should be
replaced with discrete nominal test values for lead vehicle AEB
deceleration tests.
In response to Honda, NHTSA believes that the targeted average
deceleration is best represented by a bounded range, rather than a
discrete value, to better evaluate vehicle performance. During agency
testing, NHTSA has observed vehicles that may perform well at the upper
and lower bounds of a performance range, yet inconsistently perform in
the middle of a performance range. The agency believes that specifying
a bounded range of 0.3 g to 0.5 g will better ensure consistent
performance of AEB systems in real world situations than if a discrete
value were specified. Further, the test procedures of this rule provide
information regarding how the agency will conduct tests. Manufacturers
have the flexibility to certify the compliance of their vehicles using
reasonable care, and are not required to conduct testing as the agency
does if the vehicle passes when tested by NHTSA as specified in the
standard. Therefore, this final rule adopts the average deceleration
range proposed in the NPRM.
Humanetics commented that the provision related to ``targeted
deceleration'' should state that the deceleration is maintained until
the speed is below a target value (such as 1 km/h) and that the
regulatory text ``250 ms prior to coming to a stop'' in proposed
S7.5.3a should be replaced with ``the lead vehicle speed is reduced to
1 km/h.''
NHTSA disagrees with the comment. When determining the targeted
average deceleration, the agency has specified that the targeted
deceleration will occur within 1.5 sec of lead vehicle braking onset,
giving the lead vehicle time to reach the desired deceleration. As the
vehicle comes to a stop, the acceleration profile becomes noisy and is
not reflective of the actual deceleration observed through most of the
test. Thus, the agency proposed that the last 250 milliseconds (ms) of
the vehicle braking before coming to a stop are not used in the
calculation of the targeted average deceleration. Changing this
threshold to be a speed measurement, as suggested by Humanetics, would
change the end of test parameter to allow for contact and would not
address the noise in the deceleration as the vehicle comes to a stop.
(This metric is consistent with how NCAP currently performs AEB
testing.) NHTSA concludes that the metric does not need additional
clarification and thus declines to replace the current time-based
provision with a speed-based protocol.
5. Manual Brake Application
NHTSA proposed lead vehicle AEB performance tests that included
parameters for the manual brake application made to the subject
vehicle.
NHTSA received several comments from vehicle and equipment
manufacturers on the provisions. Porsche and Volkswagen stated that
NHTSA should provide additional clarity specific to the brake robot
application, particularly regarding proposed S10 specific to the set-up
and calibration of the braking robot and the rate of brake pedal
application. Hyundai suggested removing the manual braking tests and
replacing them by a statement in FMVSS No. 127 to the effect that, ``A
driver's manual activation of the brake pedal shall not impair the
operation or effectiveness of AEB.'' ASC sought further clarification
regarding the manual brake application profile. Humanetics believed
that the tolerance was too tight in proposed S10.4 that brake pedal
force is to be maintained within 10 percent of the commanded brake
pedal force. Humanetics encouraged NHTSA to adopt a wider tolerance,
such as allowing an applied force within 25 percent of the commanded
force, while also allowing shorter duration forces (less than 200 ms)
that may exceed the 25 percent tolerance.
This final rule adopts the NPRM's proposed specifications for the
manual braking conditions. It also includes a third brake control
option that a manufacturer may choose.
The agency disagrees with Hyundai that the purpose of the manual
braking conditions can be achieved by the suggested statement. The
tests with manual braking application are different from the lead
vehicle AEB tests without manual braking. First, manual braking tests
are conducted at a higher range of subject vehicle speed, at any
subject vehicle speed between 70 km/h (43 mph) and 100 km/h (62 mph)
for both the stopped and slower-moving lead vehicle scenarios, than
that of corresponding AEB tests without manual braking application.
Second, the tests with manual braking application represent two
different real-world situations. The first represents a driver that
reacts to the FCW and re-engages in the driving task by applying the
brake (although with insufficient force to prevent a collision). In
this case, the vehicle must be capable of recognizing that the driver
has failed to provide adequate manual braking and supplement it with
automated braking force. The second represents a driver who re-engages
very late in the AEB event. The test ensures that the act of late
manual braking does not disrupt or disengage crash imminent braking
functionality.
The language suggested by the commenter considers only this second
condition and not the first. Additionally, Hyundai did not provide a
metric for ensuring that this performance could be met using their
proposed language. Therefore, NHTSA declines to remove the manual
braking test conditions in the lead vehicle AEB tests of this final
rule.
Regarding the specifications for the braking robot, the agency
notes that both Porsche and Volkswagen requested more detail but
neither explained the issues they faced, or what is needed in terms of
additional information. Both manufacturers have experienced braking
robots in other AEB testing. In the proposal, NHTSA stated that either
a displacement braking controller or a hybrid braking controller
(braking robot) could be used, at the manufacturer's discretion, and
proposed requirements for the performance of these two styles of
controllers. Additionally, the agency imposed no limitations on how
manufacturers can self-certify. Thus, manufacturers, who have the best
knowledge of their AEB systems, are free to choose a braking method
(type of braking controller, human test driver, etc.) that best serves
their needs to certify their vehicles. As Porsche recognized, various
brake robots are available with different specifications. A
manufacturer can easily select the one that is most appropriate for
testing its AEB system. Therefore, NHTSA concludes it is unnecessary to
specify a single brake controller or braking robot.
ASC sought further clarification regarding the tests that require
manual brake application on the manual brake

[[Page 39744]]

application profile. It specifically highlighted the time for driver
reaction, movement of foot brake pedal application, and build system
pressure. They also highlighted that 1.2 seconds after an FCW would be
a typical driver response time according to Euro NCAP.
As stated in the proposal, brake pedal application onset occurs 1.0
0.1 second after the forward collision warning onset,
thus, the driver response time is approximately one second. The agency
does not have data showing that a reaction time of 1.2 is more
appropriate. Specifics such as the movement of foot brake pedal
application and system pressure are best not stipulated as absolutes,
as they may change based off each brake system and in-vehicle brake
controller. The agency believes it has provided sufficient notice for
manufacturers to understand how NHTSA will test.
ASC also sought information on how the agency determines brake
pedal application onset. NHTSA does not believe that specifying a
minimum brake pedal displacement, along with a minimum level of force
applied to the pedal is necessary. To displace the pedal at all
requires a minimum amount of force. The agency believes that 11 N (2.5
lbf) of force is small enough to be easily achieved by a driver or
controller, and large enough to show intent to brake. Thus, the agency
is not adopting a change to the brake pedal application onset.
ASC highlighted that NHTSA had not considered braking systems using
force feedback. The agency agrees that a force only feedback controller
will provide another useful method of brake application. As such, the
final rule includes this third brake control option that a manufacturer
may choose. It is substantially similar to the hybrid controller with
the commanded brake pedal position omitted, leaving only the commanded
brake pedal force application. The force feedback brake pedal
application applies the force that would result in a mean deceleration
of 0.4 g in the absence of AEB activation.
6. Testing Setup and Completion
The NPRM proposed that the subject vehicle and lead vehicle speeds
are maintained within 1.6 km/h, the travel paths do not deviate more
than 0.3 m laterally from the intended travel path, and the subject
vehicle's yaw rate does not exceed 1.0 deg/s. MEMA and ASC
suggested that the lane positioning requirements should be harmonized
with UNECE Regulation No. 152, e.g., 0.2 m not 0.3 m permitted lateral
variance. Humanetics suggested that NHTSA use more strict tolerances
for the subject vehicle, to increase repeatability. Humanetics also
stated that as the yaw rate is quite a noisy signal, a filter should be
used for the lead and subject vehicles. Humanetics further suggested
that the agency should consider currently accepted tolerances to test
speeds and other test parameters in defining these FMVSS tests.
In response, NHTSA disagrees with the commenters that a tighter
tolerance is needed. The agency's specification is in line with
previous NHTSA testing. As for requiring a smaller tolerance for
vehicle speed and providing additional tolerances for a target carrier,
the agency disagrees with Humanetics that the tolerance specified is
excessively large for attaining repeatable and reliable testing. NHTSA
does not have any data showing that manufacturers cannot meet these
tolerances, nor that the tolerances proposed induce testing failures.
Additionally, requiring a tighter tolerance is not representative of
expected on road conditions. Accordingly, the agency does not see value
in providing tighter tolerances.
NHTSA also notes that the agency proposed tolerances for where the
lead vehicle will be positioned and operated during the performance
tests. NHTSA is concerned that adding more tolerances to the carrier
system that drives the vehicle test device would overly constrain the
testing set up. Lastly, ISO 19206-7 is in draft form and is yet to be
finalized. As such, it would be premature to incorporate the document
into this final rule. Given the above, the agency declines to change
lane positioning requirements or adopt additional tolerancing.
Regarding test completion, the NPRM proposed that, ``The test run
is complete when the subject vehicle comes to a complete stop without
making contact with the lead vehicle or when the subject vehicle makes
contact with the lead vehicle.'' The Alliance stated that, for the
slower-moving vehicle scenario, imposing a full braking requirement may
not be appropriate if the target/lead vehicle were to continue to move
(or if a stopped vehicle were to move again under real-world
conditions). The commenter suggested that test completion be defined as
``the instance when the subject vehicle speed is equal or less than the
lead vehicle speed without making contact with the lead vehicle, or
when the subject vehicle makes contact with the lead vehicle.''
In response, NHTSA notes that the NPRM addressed the Alliance's
concern in the proposed test procedures in proposed S7.4.4. This final
rule adopts the proposed test completion criteria--``test run is
complete when the subject vehicle speed is less than or equal to the
lead vehicle speed''--for slower moving lead AEB tests as proposed.
Bosch suggested NHTSA consider setting parameters to define a
``valid run'' with respect to pedal and steering inputs to maintain
tolerance on approach. Bosch stated that they encountered testing cases
where an overly narrow definition of the calibration tolerances of the
robot has interfered with the system reaction. Bosch also commented
that, depending on the robot mode and type of vehicle brakes utilized,
interference with the ADAS systems may occur. Bosch suggested the
adoption of tolerances outlined in UNECE Regulation No. 152 for
performance testing, with the aim of promoting standardized and
realistic evaluations of automotive safety systems.
In response to Bosch's suggestion to define what a valid run is,
NHTSA highlights the position and speed specifications for testing as
stated in the NPRM that beginning when the headway corresponds to
L0, the subject vehicle speed is maintained within 1.6 km/h
of the test speed with minimal and smooth accelerator pedal inputs.
Additionally, the subject vehicle heading is maintained with minimal
steering input such that the travel path does not deviate more than 0.3
m laterally from the intended travel path and the subject vehicle's yaw
rate does not exceed 1.0 deg/s. Bosch provided no
additional information as to the inadequacy of NHTSA's proposed
specifications for how the lead vehicle and subject vehicle respond
prior to subject vehicle braking. Additionally, Bosch did not identify
specific inadequacies in the braking controllers specified for use with
manual braking
As for the proposed triggering times/TTCs (related to the
``beginning of tests''), the ASC stated that different test procedures
in the NPRM specify different triggering times/TTCs (e.g., three (3)
seconds in S7.5.2, four (4) seconds in S8.2). ASC suggested that the
trigger time period be standardized for all test scenarios.
The agency disagrees with this TTC suggestion. NHTSA selected
appropriate test procedures, including triggering times, for each test
scenario based on its unique features. For example, a three-second
triggering time in a decelerating lead vehicle AEB test (S7.5.2) is
selected to provide sufficient time to align a subject vehicle with a
lead vehicle and to set a proper headway between the vehicles. On the
other hand, a four-second triggering time in a PAEB test (S8.2) is
selected to estimate an initial headway between a subject vehicle and

[[Page 39745]]

a pedestrian surrogate. As such, these triggering times represent
unique features of two different tests. There are reasons not to
standardize a triggering time to use across all lead vehicle and
pedestrian AEB test scenarios.
ASC sought clarification on the accelerator pedal release process
when the vehicle cruise control is active. In response, as stated in
the NPRM, when cruise control is active the pedal release process is
omitted as the accelerator pedal is already released. The agency
expects an equivalent level of crash avoidance or mitigation regardless
of whether cruise control is active.
7. Miscellaneous Comments
Mobileye stated that in some cases of target deceleration, the
robot deceleration will be enough, or close enough, to avoid a
collision. Mobileye stated that, in cases where the collision speed is
very small, the AEB system can cause a nuisance event by a slight
modification of the braking power by the driver. Mobileye suggested a
more deterministic approach for these test scenarios which will result
in a collision speed above 10 kph when using the robot 0.4 g
deceleration.
In response, NHTSA does not specify the level of deceleration that
the AEB system needs employ to safely bring the vehicle to a stop. In
fact, during testing, the agency has observed that while some vehicles
employ late and harsh braking as described by Mobileye, more refined
AEB systems do not perform in such a manner.\126\ As shown by Mobileye,
to resolve the example they provided, only a slight additional
deceleration, to further reduce the subject vehicle speed of 6.3 km/h,
is needed to avoid the collision without harsh braking.
---------------------------------------------------------------------------

\126\ https://www.regulations.gov/document/NHTSA-2021-0002-0002.
---------------------------------------------------------------------------

Bosch suggested NHTSA consider employing the term ``stationary
vehicle'' as used in the UNECE Regulation No. 152 specification,
instead of ``stopped,'' to promote uniformity and consistency in
automotive safety terminology with existing standards and
specifications. Bosch believed the distinction is crucial for some AEB
systems as ``stopped'' vehicle implies that the vehicle was in motion
immediately before the sensors have detected the Vehicle Under Test
(VUT). Bosch suggested using the term ``stationary'' instead of
``stopped'' to align with existing standards and avoid any potential
misinterpretations about the VUT as moving.
NHTSA does not agree with Bosch that the term ``stopped lead
vehicle'' should be amended to ``stationary vehicle.'' The standard's
test procedures clearly specify how the lead vehicle test device is
placed (see, S7.3.2 of the proposed regulatory text) (``the lead
vehicle is placed stationary with its longitudinal centerline
coincident to the intended travel path'') and does not lend itself to
potential misinterpretations. The term stopped, used in this
requirement, is consistent with the agency's practices in previous AEB
research and in the current U.S. NCAP.
NHTSA received several comments regarding test speeds as applied to
vehicles equipped with ADS. The Alliance, AVIA and Zoox suggested that
compliance testing be limited to the maximum speed that an ADS-equipped
vehicle can achieve within its operational design domain. AVIA
commented that some ADS-equipped vehicles have top speeds below those
required in the Lead Vehicle AEB Collision Avoidance test parameters,
and therefore suggested modifying the test parameters such that they
can be met when an ADS-equipped vehicle operates at its highest speed
if that speed is lower than the originally proposed subject and lead
vehicle speeds. Zoox commented that an ADS may ``refuse'' to drive at
80 km/h at a following distance of 12 m or at 80 kph between two parked
cars because this behavior does not align with its more conservative
driving parameters.
In response, by including a maximum speed of 90 mph in this final
rule, NHTSA is not requiring that manufacturers design their vehicles
to be capable of driving 90 mph. Similarly, NHTSA is not requiring that
Zoox design its ADS to operate at 90 mph. Instead, NHTSA may test the
vehicle at the maximum speed the vehicle can achieve in its operational
design domain. However, if the speed limitation in Zoox's vehicles are
solely due to ADS programming and the vehicle itself is not speed
limited, then Zoox must certify compliance to all speeds up to the
maximum speed its vehicles are capable of being driven. As an example,
if Zoox's ADS is programmed to drive at speeds up to 45 mph, but the
vehicle has functionality that would allow it to be driven at speeds up
to 90 mph, then Zoox must certify that AEB operates as required by this
final rule at speeds up to 90 mph.
Regarding proposed subject vehicle specifications, an anonymous
commenter stated that they found some of the procedures and criteria to
be unclear or confusing in the NPRM. They stated that NHTSA should
provide more diagrams and figures to clarify the test procedures and
criteria.
In response, NHTSA believes that the NPRM provided sufficient
information to the public to understand the requirements of the
proposed standard. The agency included many figures, diagrams, and
tables, that highlighted and explained key information. These figures,
coupled with the detailed testing scenarios and test track conditions,
adequately describe the rulemaking and the performance NHTSA is
requiring by issuing FMVSS No. 127.

I. Procedures for Testing PAEB

This section describes the pedestrian AEB performance tests adopted
by this final rule. After considering the comments to the NPRM, NHTSA
has adopted the proposed procedures tests with a few minor revisions to
some parameters and definitions, to clarify details of the test
procedures. Importantly, NHTSA has increased the lead time to meet the
requirements by providing a five-year lead time.
This section responds to the comments and explains NHTSA's reasons
for adopting the provisions set forth in this final rule. For the
convenience of readers, a list of the test specifications can be found
in appendix B to this final rule preamble.
The pedestrian AEB performance tests require AEB systems to provide
a forward collision warning (FCW) and automatically apply the service
brakes at all forward speeds above 10 km/h (6 mph) to avoid an imminent
collision with a pedestrian.\127\
---------------------------------------------------------------------------

\127\ The FCW and brake application need not be sequential.
---------------------------------------------------------------------------

The test scenarios required for PAEB evaluation fall into three
groups of scenarios based on how NHTSA will apply the pedestrian test
device--crossing path, stationary and along path. For each test
conducted under the testing scenarios, there are the following
provisions within those testing scenarios: (1) pedestrian crossing
(right or left) relative to an approaching subject vehicle; (2) subject
vehicle overlap (25% or 50%); \128\ (3) pedestrian obstruction (Yes/
No); and, (4) pedestrian speed (stationary, walking, or running)
(VP).
---------------------------------------------------------------------------

\128\ Overlap describes the location of the point on the front
of the subject vehicle that would contact a pedestrian if no braking
occurred. It refers to the percentage of the subject vehicle's
overall width that the pedestrian test mannequin traverses. It is
measured from the right or the left (depending on which side of the
subject vehicle the pedestrian test mannequin originates).
---------------------------------------------------------------------------

NHTSA will select further parameters from a subject vehicle speed
range (VSV) and the lighting condition (daylight, lower
beams or upper beams). The

[[Page 39746]]

subject vehicle's travel path in each of the test scenarios is
straight.
1. Scenarios
Request To Add Scenarios
Many commenters suggested additional scenarios in PAEB
testing.\129\ Commenters urged NHTSA to include test devices
representative of bicyclists and other vulnerable road users (VRUs),
such as motorcyclists. A number of commenters recommended expanding
additional scenarios involving pedestrians, such as older adult
pedestrians who may walk slower than 3 mph, persons with disabilities,
a running adult from the left scenario with dark lower beam or upper
beam, pedestrians crossing from both directions, or pedestrians
traveling against traffic.
---------------------------------------------------------------------------

\129\ These commenters included NTSB, Advocates, the League,
AMA, APBP, NSC, Forensic Rock, Consumer Reports, CAS, Radian Labs,
AARP, NSC, America Walks, APBP, AARP, United spinal, Radian Labs,
Adasky, VRUSC, AFB, Humanetics, and PVA.
---------------------------------------------------------------------------

NHTSA is highly interested in having PAEB address more scenarios,
road users, and pedestrians than the scenarios covered by this final
rule. NHTSA explained in the NPRM that the agency is actively
conducting research to characterize, among other matters, the
performance of AEB systems in response to bicycles and motorcycles, in
both daylight and darkness conditions. However, the state of knowledge
is not at the point where NHTSA can proceed with including bicycle and
motorcycle surrogates in the new standard at this time. To illustrate,
preliminary testing discussed in the NPRM identified issues with the
design of the bicycle and motorcycle surrogates and their effect on the
vehicles under test, indicating a need to learn more about these
devices.\130\ NHTSA is continuing its research to learn more, and
present and future studies may well result in efforts to define test
procedures, refine the bicycle and motorcycle surrogate devices, and
characterize AEB system performance for possible incorporation into the
FMVSS.
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\130\ This report is expected to be completed within 2024.
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NHTSA proceeded with this rulemaking because it has the information
needed to support an NPRM and final rule on the pedestrian behaviors
addressed by the rule. Less is known about additional pedestrian
behaviors to which commenters refer. NHTSA does not have the research
necessary to determine well-reasoned and practicable performance
requirements for the full range of travel behaviors pedestrians employ.
Because developing the technical underpinnings and assessing the
feasibility of potential further countermeasures need more time, NHTSA
is adopting the PAEB test procedures proposed in the NPRM as a sound
first step.
Request To Remove PAEB Scenarios
The Alliance requested that NHTSA not include the test of the
stationary pedestrian test in nighttime conditions (S8.4). The Alliance
stated that an analysis of real-world data from NHTSA's FARS database
showed that fewer than 5 percent of stationary pedestrian crashes occur
in dark, or low light, conditions, which is substantially lower than
the other scenarios evaluated in the NPRM. The Alliance stated that the
complexity in designing countermeasures is increased, particularly for
vision-based systems, in discerning non-moving objects that may
resemble the human form in low light conditions at high speed. The
Alliance expressed concerns that this requirement would force the
installation of additional sensors to verify the presence of an object
in the roadway. The Alliance stated that this scenario has additional
cost implications and underscores that meeting the requirements of the
rule is not as straightforward as the agency suggested.
Similarly, MEMA questioned if crash data support the stationary
pedestrian test, because the commenter believed it is unlikely a
pedestrian would be completely stationary and without movement in any
real-world condition. MEMA further stated that this test increases the
probability of false activation from other stationary roadside objects.
MEMA suggested that the moving along path scenario addresses real-world
scenarios.
In response, NHTSA declines this request to eliminate the
stationary pedestrian in nighttime conditions test. The commenters
addressed the size and existence of the safety problem, with the
Alliance providing an analysis showing that the standing pedestrian
scenario comprises 5 percent (479 lives) of unlit nighttime crashes
between 2014 and 2021. The unlit nighttime testing is designed to test
a worst-case scenario, where there is no appreciable light other than
that generated by the vehicle to aid in the detection of a
pedestrian.\131\ While the stationary position of the pedestrian test
mannequin adds to the challenge of the test, real pedestrians encounter
these potential dual dangers of darkness and stillness every day in the
real world. NHTSA testing, discussed in the NPRM, has shown that AEB
performance is reduced when testing the stationary scenario as compared
to the along path scenario. Given the certainty that there are
pedestrians outside in the dark each day, the likelihood that they may
be stationary at times and not always in motion when a vehicle
approaches, and the certainty of their vulnerable status vis-[agrave]-
vis the vehicle (even low-speed vehicle impacts with pedestrians can
result in fatalities and serious injuries), NHTSA believes that
eliminating the test would not be reasonable. This is particularly so
given that meeting the requirement is practicable.\132\ Further, even
if the agency accepts the Alliance analysis and interprets in a similar
manner ``standing'' as equivalent to stationary during PAEB testing,
NHTSA believes that the almost 50 annual fatalities over 8 years of
data lends support for adopting the proposed test.
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\131\ NHTSA expects that this performance will also be
representative of, and beneficial to, nighttime conditions where
brighter ambient light conditions exist.
\132\ NHTSA's 2023 testing demonstrated that six out of six
vehicles were able to fully meet the stationary requirements in both
daylight and upper beam nighttime scenarios. The testing showed that
half of the vehicles tested also were able to fully meet the
proposed requirements for the lower beam nighttime scenario.
---------------------------------------------------------------------------

Ford believed that some tests are redundant and requested their
removal. Ford recommends the removal of daytime 50 percent overlap
crossing use cases as this will be 25 percent redundant with crossing
use cases, as well as removing either the in-path stationary or moving
scenarios which, the commenter believed, are redundant to each other.
In response, NHTSA does not agree the tests are redundant. Testing
with a 25 percent overlap is more stringent than the 50 percent overlap
test, as the pedestrian is exposed to the vehicle for a shorter amount
of time. However, the 50 percent overlap test assesses a different
scenario than the 25 percent overlap test. In the 50 percent overlap
test, the vehicle comes upon the pedestrian later in the event. NHTSA
is retaining the 50 percent overlap test, and the other mentioned
tests, to ensure that PAEB systems are tuned to detect pedestrians
across a wide and reasonable range in the roadway.
Lack of Dynamic Brake Support (DBS) Testing in PAEB Scenarios
Unlike for lead vehicle AEB, NHTSA did not propose that the AEB
system supplement the driver's brake input with a dynamic brake support
system. This is because NHTSA believes that, due to the sudden
succession of events in a potential collision between a

[[Page 39747]]

vehicle and a pedestrian, particularly for the pedestrian crossing path
scenarios, a driver is unlikely to have enough time to react to the
crash imminent event, and the vehicle will brake automatically without
driver input. Further, NHTSA stated that it anticipates that AEB system
designs would include DBS.
Advocates commented that NHTSA should either state that manual
braking alone is insufficient to interrupt the AEB functionality or
include testing of DBS functionality in the PAEB scenarios. AARP
commented that it is important that the PAEB system function regardless
of the characteristics of the vehicle's driver, and testing should
reflect predictable variations such as those that result from the
characteristics of older drivers.
In response, NHTSA is declining to add a manual braking test for
pedestrians in this final rule. As stated in the NPRM, NHTSA expects
that manufacturers will include this functionality when approaching a
pedestrian. While the agency does not test PAEB with manual brake
application, it does not make any distinction as to when AEB is
required based on manual brake application. Thus, an AEB system tested
for manual brake application under lead vehicle AEB testing will
function in the same manner when approaching a pedestrian.
The agency also decided to test PAEB only without manual brake
application due to the timing of crashes involving pedestrians, as it
is not realistic to expect a quick enough response from a driver when
presented with a warning to mitigate a collision under the proposed
testing scenarios. NHTSA testing for lead vehicle AEB is premised on
data that often an engaged driver does not brake enough to avoid a
collision when presented with an FCW. However, the timing of a crossing
path pedestrian scenario in some cases does not afford the ability to
warn a driver and wait for a driver response. This difference between
the lead vehicle and pedestrian crash scenarios renders requiring a
manual brake application inappropriate for PAEB.\133\ As such, the
agency is declining to add a manual braking test for pedestrians at
this time.
---------------------------------------------------------------------------

\133\ NHTSA is also mindful that implementing similar manual
braking test scenarios for PAEB as for lead vehicle AEB may increase
the likelihood of false positives when the systems are driven on the
road. At 60 km/h (37.3 mph) automatic braking would need to occur at
a minimum distance to the pedestrian of 20.25 meters with a 0.7g
stop, which is a TTC of 1.21 sec, and it takes the vehicle 2.4 sec
to stop. A pedestrian traveling with a walking speed of 5 km/h (3.1
mph) would cover 3.36 meters in this time, which puts that
pedestrian 3.8 meters from the center of an average vehicle in the
25 percent overlap scenario, or about 2.9 meters from the side of
the vehicle. In an urban setting, this would place the pedestrian in
the buffer zone between the sidewalk and the travel lane, indicating
the intent to cross the street. In this scenario the pedestrian
would be a further 1.38 meters away in case of a warning issued 1
second prior to the minimum TTC described above, or more with a
longer warning. This would place a pedestrian outside the buffer
zone and solidly on the sidewalk. Adding additional time for a
forward collision warning and driver reaction time increases the
likelihood of false alerts, as it becomes increase difficult to
determine the pedestrian's intent the further outside the travel
lane the pedestrian is. Because of this, NHTSA proposed requiring,
``The vehicle must automatically apply the brakes and alert the
vehicle operator such that the subject vehicle does not collide with
the pedestrian test mannequin when tested using the procedures in S8
under the conditions specified in S6.''
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Lack of 25 Percent Overlap for PAEB Scenarios in Dark Conditions
Several comments suggested including PAEB performance tests with 25
percent overlap in dark conditions. Advocates requested that testing
requirements at 25 percent overlap be included in the proposal, as a
quarter of the vehicles tested by NHTSA in a limited study included
such capability. Luminar stated the proposed PAEB testing overlap is
arbitrary since the NPRM proposes PAEB testing at 25 percent overlap,
but only 50 percent overlap for other scenarios, including some
nighttime tests.
In response, as discussed in the NPRM, NHTSA declined to add the 25
percent overlap scenario for nighttime pedestrian AEB because it is not
practicable at speeds relevant to the safety problem. The final rule
has more benefits when pedestrian avoidance is tested at a more
stringent and higher speed 50 percent overlap scenario.
NHTSA disagrees with Luminar that the overlap scenarios are
arbitrary. UNECE Regulation No. 152 specifies the pedestrian target's
positioning at the same location as a 50 percent overlap scenario. Euro
NCAP also uses impact locations of 25, 50, and 75 percent. NHTSA still
views testing at high speeds with a 25 percent overlap during nighttime
scenarios as not practicable. The agency views setting higher speed
tests for crossing path with a 50 percent overlap at night as merited
and more appropriate for this final rule than specifying lower max
speeds for a 25 percent overlap at night. Accordingly, NHTSA is
declining to add a scenario for a high-speed test with a 25 percent
overlap during nighttime condition.
Lack of Turning Scenarios
Several commenters recommended the inclusion of turning scenarios
as part of the PAEB test requirements, i.e., expanding the testing
conditions to evaluate pedestrian during right and left turns of the
subject vehicle.\134\ Luminar stated that turning real word traffic
conditions that mimic common pedestrian encounters in which the
subject's movement partially or momentarily obscured and performance of
crash avoidance technology in these scenarios is achievable. Some
commenters stated that turning car-to-pedestrian AEB testing is
performed as part of Euro NCAP.
---------------------------------------------------------------------------

\134\ These commenters included Forest Rock, Luminar, APBP, NSC,
the Coalition, Consumer Reports, and AARP.
---------------------------------------------------------------------------

In response, this final rule adopts the tests as proposed based on
the research and other data demonstrating the efficacy and
practicability of systems meeting the crossing path, stationary and
along path scenarios. The data and technologies for test scenarios
representing other crashes have not been analyzed as to their merit for
inclusion in a possible FMVSS (as discussed throughout this document,
rear-end crashes have been analyzed).
NHTSA included pedestrian AEB in turning from the left and turning
from the right as a potential regulatory alternative for a more
stringent rule. While commenters pointed out that Euro NCAP and other
world NCAP programs offer some turning scenarios, NHTSA does not have
sufficient information to propose or finalize incorporating a turning
scenario at this time. NHTSA is not selecting this alternative in this
final rule, however, and will consider conducting additional research
and adopting requirements for turns in a future rulemaking, as
appropriate. As discussed in the NPRM, NHTSA focused on the practicable
scenarios that have the largest impact on the safety problem. While
turning scenarios are responsible for around 48 percent of the total
crash population for pedestrians, NHTSA crash data shows that 90
percent of fatal pedestrian-vehicle crashes, and 52 percent of the
total pedestrian-vehicle crash population are covered under the
standard NHTSA has developed.\135\ In contrast, NHTSA data found that
the turning right and turning left scenarios were found to only account
for 1 percent and 4 percent of pedestrian fatalities, respectively.
---------------------------------------------------------------------------

\135\ Mikio Yanagisawa, Elizabeth D. Swanson, Philip Azeredo,
and Wassim Najm (2017, April) Estimation of potential safety
benefits for pedestrian crash avoidance/mitigation systems (Report
No. DOT HS 812 400) Washington, DC: National Highway Traffic Safety
Administration, p xiii.

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[[Page 39748]]

2. Subject Vehicle Speed Ranges
Increase PAEB Testing Speeds
Comments
NHTSA received many comments requesting the agency to increase the
test speed of the vehicle.\136\ Commenters generally stated that since
the most common speed limit for a road where a pedestrian is killed is
45 mph, PAEB testing speeds should be increased above the proposed
speeds (they generally did not suggest a maximum testing speed).
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\136\ These commenters included the cities of Philadelphia,
Nashville and Houston, the Richmond Ambulance Authority, Drive Smart
Virginia, Teledyne, the Lidar Coalition, Luminar, Consumer Reports,
Forensic Rock, Luminar, COMPAL, and NACTO.
---------------------------------------------------------------------------

Agency Response
In response, as explained in the earlier section for lead vehicle
testing speeds, NHTSA has bounded the testing speeds after considering
practicability and other issues. These practicability concerns include,
among others, the performance that can reasonably be achieved in the
lead time provided for the final rule, the safety need that can be
addressed, the safety of the testing personnel, and the practicalities
of conducting a test that can be run repeatably and consistently
without damaging lab equipment, to preserve the integrity and validity
of the test data. NHTSA proposed and is adopting the highest
practicable testing speeds. Accordingly, NHTSA has decided not to
increase the test speeds for PAEB in this final rule. NHTSA considered,
and is currently researching, other testing scenarios for PAEB, so more
will be known about the future about the practicability and
reasonableness of higher test speeds.
Reduce PAEB Testing Speeds
Comments
NHTSA received many comments from manufacturers and others
requesting the agency to decrease the test speed of the vehicle.\137\
Some manufacturers commented that NHTSA should permit low impact speeds
when testing PAEB above certain testing speeds (when testing 30 km/h
(19 mph) and above).
---------------------------------------------------------------------------

\137\ These commenters included the Alliance, Honda, Mobileye,
Mitsubishi, Porsche, Volkswagen, Nissan, Toyota, and Aptiv.
---------------------------------------------------------------------------

Like their comments on the lead vehicle speed tests, the Alliance
and others suggested a hybrid approach that would permit some level of
contact with the pedestrian test device for speeds above, e.g., 30 km/h
(19 mph). These commenters stated that providing full crash avoidance
at higher speeds may not always be practicable due to increased
potential for false positives under real world conditions.
Additionally, the Alliance stated that the PAEB system must have
sufficient information upon which to base its decision to apply braking
force. The high testing speeds and no-contact requirement may force the
AEB system to be too aggressive particularly in view of what can be
unpredictable movement of pedestrians in and around the roadway
environment. Honda suggested when PAEB is tested between 50 km/h and 65
km/h (31 mph to 40 mph), NHTSA should allow low speed contact up to 15
km/h (9.3 mph). Honda stated that the basis for the suggested speed
threshold is that according to pedestrian injury data in the U.S., the
risk of severe injury or fatality in pedestrian crashes below 15 km/h
is highly unlikely.
The Alliance expressed concern about false positives or bad actors
seeking to manipulate the AEB system into activating by imitating the
act of entering the roadway environment. Mitsubishi was concerned about
pedestrians who are about to jaywalk but stop due to approaching cars.
The commenter stated that this behavior may lead to unnecessary
activation and induce unintended consequences as current technology
cannot predict pedestrian behavior with 100% accuracy. The Alliance and
others stated that impact speeds of 25 km/h (16 mph) should be allowed
as such impact speeds would have a reasonable safety outcome when the
crash speed was mitigated from a higher speed testing. Some commenters
stated that NHTSA should harmonize with UNECE Regulation No. 152, where
impact speeds up to 40 km/h (25 mph) are allowed.
Agency Response
NHTSA is adopting the proposed testing speed ranges with a no-
contact requirement and is not permitting repeat trials.
The commenters' main arguments in support of reducing the PAEB
testing speeds are the potential increase in the likelihood of false
positives due to difficulties in detecting pedestrians and classifying
pedestrian action (such as intention to enter the roadway). In general,
the commenters suggested allowing some level of pedestrian contact at
above certain reduced speeds, ranging from 30 km/h to 50 km/h (10 mph
to 31 mph), with most commenters suggesting around 40 km/h (25 mph) as
the maximum speed for a no-contact requirement.
NHTSA proposed testing requirements that can be met, and that can
avoid as many crashes, and mitigate as much harm, as practicable. For
PAEB, NHTSA seeks to avoid crashes at the highest practicable speeds
because of the vulnerability of a pedestrian in a vehicle crash.
Vehicle contact with a pedestrian can be fatal or result in serious
injury with potential long-term effects. NHTSA scrutinizes hybrid
approaches, such as that of the Alliance, that incorporate as part of
its framework the vehicle's hitting a pedestrian because the risk of
injury to a pedestrian in a vehicle crash is so great. After reviewing
the comments and other information, NHTSA does not believe that
striking a pedestrian is an acceptable safety outcome given the
availability of technologies that can prevent any kind of contact in
the test scenarios.
Using the speed limit as a proxy for traveling speed, the data
presented in the previous section of this document show that about 50
percent of pedestrian fatalities, and about 57 percent of injuries,
occur on roads with a speed limit of 65 km/h (40 mph) or less. NHTSA
believes an upper speed limit less than 65 km/h (40 mph) for a no-
contact PAEB requirement would not be appropriate when test data on the
performance of current vehicles show the practicability of meeting the
proposed limits, particularly when more lead time is provided for the
technology to evolve.
The injury curves and thresholds provided by some of the commenters
show that below 25 km/h, there is a reduced probability of AIS3+ and
MAIS3+ injury compared to impacts at greater speeds. However, the
safety problem that PAEB can mitigate exists mainly at speeds above 40
km/h. Given that AEB, when developed to meet a no-contact requirement,
could help mitigate the occurrence of pedestrian impacts up to 65 km/h
(40 mph), NHTSA believes it unreasonable to set the no-contact limit at
speeds at just a 40 km/h (25 mph) threshold.
As demonstrated by NHTSA testing, the technology has already proven
effective at avoiding collisions at speeds up to 65 km/h (40 mph). As
detailed in the research section, NHTSA found that a vehicle (the 2023
Toyota Corolla Hybrid) was able to avoid collision under all testing
conditions up to the maximum proposed testing speeds requirement for
all PAEB testing scenarios and speeds.\138\ In addition,

[[Page 39749]]

four of the six vehicles tested achieved collision avoidance up to the
proposed maximum speeds in almost all scenarios-some even in the most
challenging dark lower beam scenarios. Additionally, another vehicle
was able to achieve collision avoidance at all tested speeds in 3
scenarios.
---------------------------------------------------------------------------

\138\ NHTSA's 2023 Light Vehicle Pedestrian Automatic Emergency
Braking Research Test Summary, available in the docket for this
final rule (NHTSA-2023-0021).
---------------------------------------------------------------------------

NHTSA believes that the practicability of meeting the PAEB
requirements of this final rule is demonstrated by the test data
showing the performance of the 2023 Toyota Corolla Hybrid that passed
all scenarios, and that of the several other vehicles that almost
passed all scenarios. These test results are even more noteworthy
because the tested vehicles did not have AEB systems designed to meet
the requirements of proposed FMVSS No. 127. They were not prototypes or
vehicles specially engineered to the specifications of the proposed
standard for research purposes. To be clear, these were production
vehicles already in the marketplace. The fact that current vehicles not
particularly engineered to meet the new standard's requirements could
meet them as designed, or with slight modification, further
demonstrates the practicability of this final rule. Because current AEB
systems are already capable of meeting the AEB requirements, NHTSA's
assumption is confirmed that manufacturers will be able to meet the
requirements of FMVSS No. 127 with the lead time provided, without
major upgrades while mitigating excessive false positives or other
unintended consequences.
Several commenters also believed that repeated trials should be
allowed during PAEB testing. In response, NHTSA notes that the agency
does not usually incorporate repeated trials in its vehicle compliance
program. NHTSA's position has been to conduct a compliance test and, if
an apparent noncompliance results, the agency should pursue the matter
with the vehicle manufacturer without having to run a repeated trial.
NHTSA's view is that the vehicle manufacturer is responsible for
certifying the compliance of its vehicles and for ensuring the basis of
its certification is sufficiently robust such that each vehicle will
pass the test when tested by NHTSA. The agency acknowledges that for
many years, NCAP testing (and other testing around the world) has
encompassed repeated test trials to populate information about AEB in
the consumer information program. NHTSA took the repeated trial
approach in NCAP only because it was for a technology that was new or
being developed. For more mature systems with a substantial record of
real-world use, a single test run is preferable. A single test approach
provides the agency the confidence that the performance it is
regulating will perform as consistently as possible in the real world.
Regarding the comments received relating to AEB perception,\139\
pedestrian detection, and classification, the MY 2023 vehicles tested
for PAEB were generally able to avoid collision in all scenarios and at
the majority of higher testing speeds. These vehicles are in production
and on the road, demonstrating that solutions have been engineered to
the PAEB perception in the real world. The engineering solutions have
also accounted for no-contact testing performance. Also, Euro NCAP,
while not a regulation, employs similar testing at similar speeds as
the requirements in this final rule and many vehicles achieve a full
score on Euro NCAP testing due to their collision avoidance
capabilities. This performance further reinforces NHTSA's assessment
that meeting the testing speeds of this final rule are practicable.
---------------------------------------------------------------------------

\139\ The performance of each AEB system depends on the ability
of the system to use sensor data to appropriately detect and
classify forward objects. The AEB system uses this detection and
classification to decide if a collision is imminent and then avoid
or mitigate the potential crash. Manufacturers and suppliers of AEB
systems have worked to address unnecessary AEB activations through
techniques such as sensor fusion, which combines and filters
information from multiple sensors, and advanced predictive models.
---------------------------------------------------------------------------

Evasive Steering (PAEB)
Comments
For the small overlap (25% test conditions), Porsche stated the
last point to steer is much closer to the pedestrian than the last
point to brake and the proposed test speeds may increase the likelihood
for emergency braking engagement that may often be perceived by the
customer as a false activation in scenarios where the driver is aware
of the pedestrian on the road and planning to steer around them.
Porsche stated that this dilemma is similar to high speed AEB for lead
vehicles, but occurs at lower speeds, as small overlap pedestrian
scenarios are harder to detect and predict.
Agency Response
In response, after considering the comments, and similar to its
assessment of comments regarding lead vehicle evasive steering, the
agency is not persuaded that evasive steering is an acceptable
avoidance maneuver during testing. As thoroughly discussed previously,
such factors as vehicle dynamics, traffic conditions and traffic
participants all influence the safety benefit of a steering avoidance
maneuver. A steering maneuver, as an avoidance maneuver, may not be as
safe as a brake-in-lane maneuver, particularly in an urban environment.
In any event, like for the lead vehicle situation, a manufacturer,
outside of the testing requirements, may elect to detune or disengage
the AEB system based on an emergency steering maneuver as long as the
vehicle meets all the AEB requirements.
3. Pedestrian Test Device Speed
Comments
AARP and ASC commented on the proposed pedestrian test device
speeds. AARP suggested that NHTSA consider whether testing the adult
pedestrian scenarios at a walking speed of 3.1 mph (5 km/h) is
sufficient to improve safety for those who walk at slower speeds. ASC
stated that IIHS, and UNECE Regulation No. 152 and No. 131, require a
speed of less than or equal to 5 km/h, which is representative of a
walking adult pedestrian.
Agency Response
In response, NHTSA believes that the proposed crossing path test
speed of 5 km/h (3.1 mph) for walking adult scenarios reasonably
addresses the safety of adult pedestrians, including those who walk at
slower speeds. Higher pedestrian test device walking speeds are more
challenging for AEB systems. The longer a pedestrian is in the roadway,
the more time a vehicle has to identify, classify, and avoid striking
the pedestrian. NHTSA proposed that tests be performed at 5 km/h (3.1
mph) and 8 km/h (5 mph), as these speeds are representative of able-
bodied adults walking and running. The agency expects that
manufacturers will not turn pedestrian avoidance off at pedestrian
speeds below those tested but will instead design systems that detect
pedestrians moving at speeds lower than 5 km/h (3.1 mph) and avoid
them. Further, the agency also included in the requirements testing
with stationary pedestrian test devices, so that PAEB performs under
three distinct pedestrian test mannequin speed scenarios (0 km/h, 5 km/
h and 8 km/h). Therefore, NHTSA declines to include additional tests
with pedestrian surrogate speeds lower than 5 km/h (3.1 mph) based on
the absence of a safety need to do so.
In response to ASC, NHTSA notes that the 8 km/h (5 mph) test speed
is used in the pedestrian crossing from the left scenario. It is
representative of an able-bodied pedestrian running. This

[[Page 39750]]

performance test was proposed in the NPRM to ensure that pedestrian
avoidance occurs in as wide a range of scenarios as is practicable.
Data from NHTSA's testing of six model year 2023 vehicles showed that
four of the six vehicles were able to meet the performance levels
proposed in the NPRM. Based on the above, NHTSA concludes this test
scenario is practical and appropriate for inclusion in the final rule.
The agency also expects that if manufacturers can meet this performance
for pedestrians crossing from the left at 8 km/h (5 mph), they can also
avoid slower moving pedestrians, because in general the slower moving
scenario poses a less demanding performance condition.
After considering the comments, the final rule adopts the 5 km/h (3
mph) speed for walking adult scenarios and the 8 km/h (5 mph) speed for
running adult scenarios in crossing path PAEB tests, as proposed in the
NPRM.
4. Overlap
Bosch commented on NHTSA's use of the term ``overlap'' in the NPRM.
Overlap is a term used to describe the location of the point on the
front of the subject vehicle that would make contact with a pedestrian
if no braking occurred. The NPRM defined overlap as the percentage of
the subject vehicle's overall width that the pedestrian test mannequin
traverses. It is measured from the right or the left, depending on the
side of the subject vehicle where the pedestrian test mannequin
originates.
NHTSA proposed to use two overlaps for testing: a 25 percent
overlap and a 50 percent overlap. The agency proposed the minimum
overlap of 25 percent to allow for the test mannequin to fully be in
the path of the subject vehicle. The agency also explained that the
overlap determines the available time for the AEB system to detect and
react when a collision with the test mannequin is imminent--a 50
percent overlap allows for more time than a 25 percent overlap. As for
tolerances, the NPRM proposed that for each test run, the actual
overlap would have to be within 0.15 m of the specified overlap.
Bosch did not object to the meaning of the term, the values
proposed, or the tolerance provided for overlap, but suggested that
NHTSA consider using the phrase ``percentage of the vehicle's width,''
rather than ``overlap.'' The commenter believed that the phrase
accurately describes the lateral distance between the person in front
of the vehicle and is terminology used by Euro NCAP. Bosch further
stated that a similar approach by NHTSA would promote consistency and
comparability in AEB performance evaluation across the industry.
In response, NHTSA declines to change the term ``overlap.'' The
agency believes that the term overlap used in the proposal, and
``percent vehicle width'' used in Euro NCAP, are synonymous and not in
conflict. Furthermore, the use of ``overlap'' is consistent with
NHTSA's use of terms in its crashworthiness regulations, NHTSA's NCAP
program, and NHTSA's practices in previous PAEB research. In addition,
the definition of ``overlap'' in S8.1.2--the percentage of the subject
vehicle's overall width--already includes the phrase put forth by
Bosch.
5. Light Conditions
This final rule adopts the proposed requirements in the NPRM to
specify compliance testing of AEB systems in daylight and dark
conditions. The conditions ensure performance in a wide range of
ambient light conditions. For daylight testing, the ambient
illumination at the test site is not less than 2,000 lux. This minimum
level approximates a typical roadway light level on an overcast day.
The acceptable range also includes any higher illumination level
including levels associated with bright sunlight on a clear day. For
PAEB testing in darkness, the ambient illumination at the test site
must be no greater than 0.2 lux. This value approximates roadway
lighting in dark conditions without direct overhead lighting with
moonlight and low levels of indirect light from other sources, such as
reflected light from buildings and signage.
Comments
NHTSA received many comments to the proposed light conditions.
Consumer advocacy groups and others generally support the proposed PAEB
tests in daylight and darkness (with lower and upper beam)
conditions.\140\ NSC and GHSA emphasize that 75 to 77 percent of
pedestrian fatalities occur in darkness or after dark, regardless of
whether artificial lighting was present. GHSA also states that
disadvantaged communities are overrepresented in pedestrian fatalities.
Consumer Reports is supportive of PAEB in dark conditions based on the
overrepresentation of nighttime pedestrian crashes among the total.
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\140\ These commenters included NSC, NTSB, GHSA, Consumer
Reports, Forensic Rock, the Lidar Coalition, ZF, and COMPAL.
---------------------------------------------------------------------------

With respect to the use of headlamps during PAEB testing, Consumer
Reports believes there does not appear to be a significant advantage of
testing with the upper beams if the system already meets the
requirements with the lower beams, and, that there is no guarantee that
drivers will use the upper beams. In addition, Consumer Reports
anticipates an increasing number of vehicles will be offered with
adaptive driving beam (ABD) technology that can be used rather than
lower beam and upper beams, and suggests that NHTSA's AEB tests test
with ADB. Therefore, Consumer Reports suggests NHTSA replace the lower
and upper beam language with language referring to the ``lowest level
of active illumination,'' or similar, and require that the system pass
the test at this level of lighting. Some equipment manufacturers
expressed support for the proposed PAEB tests in daylight and darkness
conditions, stating that infra-red sensors would increase safety for
dark lighting conditions.
The Lidar Coalition expressed strong support for the proposed
testing of PAEB in low light conditions with no overhead lighting and
only lower beams activated. The commenter states that NHTSA is
correctly focusing on addressing the largest portion of pedestrian
fatalities on U.S. roadways. The Lidar Coalition suggests that NHTSA
prioritize testing in the darkest realistic conditions possible. The
commenter states that the proposed test procedure in dark conditions
will evaluate PAEB technologies in the real-world scenarios where the
commenter believes these systems are most needed, when the human eye
falls short. The Lidar Coalition states the Insurance Institute for
Highway Safety found that in darkness conditions, camera and radar
based PAEB systems fail in every instance to detect pedestrians. They
additionally referenced the GHSA finding that in an evaluation of
roadway fatalities in 2020, 75% of pedestrian fatalities occur at
night.
COMPAL supports a finding of a safety need for PAEB under dark
condition and higher speeds (greater than 60 km/h (37.5 mph)), and
believes that placing infrared sensors as a forward-looking sensor in
PAEB testing can improve AEB functionality in challenging situations,
such as testing for the crossing child obstructed scenario and the
crossing adult running from the left. It states that infrared sensors
should not be considered an emerging technology and that they work well
in sun glare and darkness conditions and can detect a pedestrian much
further than typical headlamps.
Vehicle manufacturers and equipment manufacturers generally oppose
the proposed PAEB dark test conditions with only low beams because of
the

[[Page 39751]]

limited ability to illuminate pedestrians. The Alliance, Ford, Nissan,
Toyota, Honda, MEMA, Mobileye and Adasky support the idea of allowing
the use of the advanced lighting technology (such as ADB headlamps) if
available on the model as standard equipment, or to incorporate the use
of streetlights to simulate urban traffic conditions. The Alliance
argues that allowing all dark lighting conditions to be tested with the
advanced lighting features activated aligns with NHTSA's considerations
for similar testing in the proposed NCAP upgrade and further promotes
the adoption of these advanced lighting systems. Porsche states that
the required nighttime PAEB performance requirements at the higher
relative speeds is likely to exceed the technical capabilities of many
current AEB system hardware. MEMA states that, in dark environments
without streetlights, the lower beams would not be active because upper
beams provide a better view, so this lower beam test is not depicting a
real driving situation.
Ford and Nissan also state that the lighting requirements in FMVSS
No. 108 impact feasibility and practicability in testing certain low
light PAEB tests. Similarly, Honda commented that the primary sensor
for detecting pedestrian targets is the camera, which relies on optical
information. Honda state this exceeds the recognition capability and
reliability range of current camera systems and will lead to excessive
false activations.
Agency Response
After considering the comments, NHTSA has determined there is a
safety need for the dark testing requirement, given the number of
nighttime pedestrian fatalities and IIHS's finding that several AEB
systems that performed well in daylight performed poorly in dark
conditions. The agency has adopted the dark lighting requirements as
proposed. However, as explained in the discussion below, NHTSA concurs
that more time is needed to meet the dark lighting conditions. This
final rule provides five years of lead time to do the additional
engineering work needed to bring poorer performing AEB systems to a
level where they can meet this final rule's requirements.
Consumer Reports commented that testing with upper beam may be
redundant if the system already meets the requirements with the lower
beam. While this might be true for some systems, agency testing
performed for the NPRM showed inconsistent performance while testing
with the upper beam.\141\ In rare cases, vehicles performed better with
lower beams illuminated than with upper beam. NHTSA is adopting an
upper beam test to assure the functionality of the AEB system when the
driver uses the upper beam.
---------------------------------------------------------------------------

\141\ https://www.regulations.gov/docket/NHTSA-2023-0021/document (last accessed 12/8/2023).
---------------------------------------------------------------------------

Forensic Rock, Lidar Coalition, COMPAL and ZF, appear to assert
that all scenarios should be tested under dark and daylight condition,
or that testing should be performed in the darkest realistic condition.
NHTSA does not concur with that view, as the agency must consider,
among other matters, the safety problem being addressed (to ensure the
FMVSSs appropriately address a safety need), and the practicability and
capabilities of the technology. NHTSA has assessed the tests and
performance requirements adopted in this final rule to ensure each
satisfies the requirements for FMVSS established in the Safety Act.
Some tests did not pass NHTSA's assessment and were not proposed. To
illustrate, the test results for the crossing scenarios at 25% overlap
at night indicate meeting the test is impracticable at this time.\142\
Similarly, the obstructed child scenario depicts a situation that very
rarely occurs at night (as noted by ZF as well), so NHTSA did not
propose testing for such a scenario at night as not practical or
reasonable.\143\
---------------------------------------------------------------------------

\142\ https://www.regulations.gov/docket/NHTSA-2023-0021/document.
\143\ Id.
---------------------------------------------------------------------------

Many commenters believe that testing should be allowed with the
adaptive driving beam (ADB) active. NHTSA disagrees. NHTSA does not
require ADB, whereas the lower beam and upper beam are required by the
FMVSSs on the vehicle. Further, even if an ADB system were installed on
the vehicle, a driver may not use it. NHTSA does not believe it
appropriate to tie the life-saving benefits associated with AEB to a
technology (ADB) that a driver may or may not use on a trip.
Additionally, ADB still employs the lower beam and upper beam, and
merely switches automatically to the lower beam at times appropriate to
do so. Thus, even if a driver has ADB operational, if the ADB reverts
to a lower beam on a large portion of the beam area, in effect the
operating conditions would be lower beam only, which, under the
commenters' suggested approach, would not have been assessed with AEB.
Testing PAEB with ADB on could, under the commenters' suggested testing
conditions, essentially amount to the agency only testing the upper
beam condition. Such an outcome would be undesirable from a safety
standpoint, as most drivers rarely use their upper beams when operating
vehicles at night. IIHS test data of 3,200 isolated vehicles (where
other vehicles were at least 10 or more seconds away) showed that only
18 percent had their upper beams on.\144\ At one unlit urban location,
IIHS data showed that upper beam use was less than 1 percent. IIHS
found that even on rural roads, drivers used their upper beams less
than half of the time they should have for maximum safety, on average.
Testing during daylight and dark with lower beam and upper beam
provides confidence that in urban dark lighted environment, PAEB will
perform even with only the lower beam operational.
---------------------------------------------------------------------------

\144\ https://www.iihs.org/news/detail/few-drivers-use-their-high-beams-study-finds (last accessed 11/18/2023).
---------------------------------------------------------------------------

NHTSA understands that lower beam testing scenarios may require
better lowlight cameras and may require improved recognition algorithms
for the lower performing AEB systems, which is why the agency is
affording manufacturers additional time to engineer such systems up to
FMVSS No. 127 performance. NHTSA's testing conducted for the NPRM
indicated that the proposed PAEB dark scenarios represent ambitious,
yet achievable performance criteria.\145\ The latest agency research,
detailed in this notice, on six model year 2023 vehicles found that in
the scenario where the pedestrian is approaching from the right, five
of the six vehicles tested were able to meet the performance
requirements for the upper beam lighting condition, and four of the six
were able to meet the lower beam lighting condition. In the scenario
where the pedestrian is stationary, all vehicles were able to meet the
upper beam light condition, and three of the six vehicles were able to
meet the lower beam testing condition. The final nighttime scenario,
with the pedestrian moving along the vehicle's path, four vehicles met
the performance requirements for the upper beam condition, and a single
vehicle met the lower beam condition. The 2023 Toyota Corolla was able
to avoid collision in two instances and had impact speeds of about 5
km/h or less in the other three tests.
---------------------------------------------------------------------------

\145\ https://www.regulations.gov/docket/NHTSA-2023-0021/document (last accessed 12/8/2023).
---------------------------------------------------------------------------

These data indicate the practicability of meeting the PAEB tests
proposed in the NPRM. Although not all manufacturers can currently
certify to

[[Page 39752]]

all dark tests, AEB technologies are evolving rapidly, with significant
improvements occurring even in the last year or two of NHTSA's AEB
research program. NHTSA is providing five years for further development
and integration of the technology into the new vehicle fleet. The
agency adopts the upper and lower beam conditions as proposed in the
NPRM without change, except for providing more lead time to meet the
standard's requirements.
As for Honda's concerns about the sensors that they use, i.e.,
cameras, NHTSA is aware of different sensor combinations capable of
detecting pedestrian mannequins, as is evidenced by the higher
performing vehicles identified during NHTSA testing. While Honda's
current generation cameras may have recognition capability and
reliability range challenges, other sensors and sensor combinations do
not. NHTSA is not required to limit performance requirements to what
one particular manufacturer using specific sensors is capable of doing
at a given point in time. If Honda faces the challenges it describes,
then software and possibly hardware updates may be necessary for Honda
to meet the require performance.
6. Testing Setup
Pedestrian, Obstructed Running Child, Crossing Path From the Right
In the test of an obstructed running child crossing from the right,
an obstructed child pedestrian test device moves in the vehicle's
travel path from the right of the travel path. The pedestrian surrogate
crosses the subject vehicle's travel path from in front of two stopped
vehicle test devices (VTDs). The VTDs are parked to the right of the
subject vehicle's travel path, in the adjacent lane, at 1.0 m (3 ft)
from the side of the subject vehicle. The VTDs are parked one after the
other and are facing in the same direction as the subject vehicle. The
subject vehicle must avoid collision with the child pedestrian
surrogate without manual brake input.
Comments and Agency Responses
Porsche, Volkswagen, FCA, and ASC commented on the proposed
obstructed pedestrian scenario in PAEB performance tests. Porsche and
Volkswagen stated that the distance between the pedestrian test dummy
and the farthest obstructing vehicle is not specified in the proposed
regulation (i.e., S8.3.3). The commenters believe this is critical to
be defined because the level of obstruction of the child test dummy can
only be defined by this distance. If multiple distances are required to
reflect full and partial obstruction, then each specific test scenario
should be defined.
In response, NHTSA agrees with the commenters that the proposed
testing setup should have, but did not, include the distance between a
pedestrian test mannequin and the obstructing vehicle device positioned
further from a subject vehicle. In this final rule, NHTSA adopts the
following regulatory text language to clarify the test setup for the
obstructed pedestrian crossing scenario: ``[t]he frontmost plane of the
vehicle test device furthermost from the subject vehicle is located 1.0
0.1 m from the parallel contact plane (to the subject
vehicle's frontmost plane) on the pedestrian test mannequin.''
ASC stated that the vehicles obstructing the mannequin should be
specified. The commenter believes that due to the large size of common
vehicles sold in the US (e.g., pick-ups and sport utility vehicles),
specific vehicle models or types should be defined for this test
configuration.
In response, the agency disagrees with ASC that NHTSA should
specify models or types of the obstructing vehicles. The regulatory
text specifies that two vehicle test devices are used as an obstruction
in obstructed pedestrian crossing tests and the text also provides the
dimensional specifications and other measurements of the vehicle test
device. Therefore, the standard includes sufficient information
specifying the obstructing vehicles to ensure repeatable and
reproducible testing.
FCA commented that the obstruction vehicles in the research testing
were a Honda Accord and Toyota Highlander and every research test used
this combination of real vehicles as obstructions, but that there was
no data in the NPRM or the research about how these scenarios react or
correlate to the vehicle test devices proposed for the FMVSS at
S8.3.3(g). FCA expressed concern that this could lead to added
practicability or other concerns for the associated test condition.
In response, NHTSA highlights the additional testing performed. In
this course of this testing, NHTSA evaluated using real vehicles, the
4Active vehicle test device, and the ABD test device.\146\ The agency
found no appreciable differences in performance between real vehicles
and either vehicle test device. Thus, NHTSA believes that using the
vehicle test device in the obstructed child crossing scenario is
practicable and reasonable.
---------------------------------------------------------------------------

\146\ ``NHTSA's 2023 Light Vehicle Automatic Emergency Braking
Research Test Summary'' Available in the docket for this final rule
(NHTSA-2023-0021).
---------------------------------------------------------------------------

With respect to Bosch's suggestion that the maximum allowed travel
path deviation needs to be specified as \1/8\th of the subject vehicle
width and not the 0.3 m allowed in the proposal, the agency agrees in
general that the tolerance for the expected point of contact should be
from the subject vehicle and not the lane. Thus, in the proposal, the
tolerance for the expected contact point was specified as the
difference between the actual overlap and the specified overlap. This
tolerance was specified and is finalized independent of the vehicle's
position in the lane. The NPRM's proposed regulatory text stated: ``For
each test run, the actual overlap will be within 0.15 m of the
specified overlap.'' This is a tighter tolerance than Bosch suggested
(\1/8\th of the average vehicle width is approx. 0.22 m). As such, the
agency does not believe this will allow the situation Bosch proposed
(where 25 percent overlap can be mistaken for a 50 percent overlap, and
50 percent overlap can be mistaken for 25 percent overlap from the
left) to occur.
FCA suggested that NHTSA should consider using a standard road
width and simply positioning the pedestrian mannequins across
percentages of the lane, as this would be indicative of a position in
the real world. FCA stated that NHTSA intended to position pedestrians
according to ratios derived from the overall width of each vehicle, but
that this set up can be overly complicated.
NHTSA disagrees with FCA that applying mannequin positions--
described as percentages of the width of a standard test lane--would
simplify test procedures. First, the agency is not aware of a standard
test lane specification that is universally accepted for PAEB tests,
and which can represent various types of roads in the real-world. Such
roads would include lanes marked by two lines on highways, lanes marked
by only one line in urban residential sections, and lanes without any
marking in rural areas. Second, applying a same mannequin position
within the test lane for all PAEB tests could cause unnecessary
confusion because it might result in different overlap scenarios for
different sizes of subject vehicles. For example, a pedestrian
mannequin positioned at a certain percentage of the lane width may be
appropriate for a 25 percent overlap test with a full-size pickup
truck. However, such positioning may result in an invalid test with a
small compact car--for example, a Fiat 500--since a mannequin at the
same lateral

[[Page 39753]]

position within the test lane may not make a contact with such a small
subject vehicle. Therefore, NHTSA declines to adopt a mannequin
position that is defined by lane width and not percent overlap.

J. Procedures for Testing False Activation

This section describes the false activation performance tests
adopted by this final rule. These tests are sometimes referred to as
``false-positive'' tests. After considering the comments to the NPRM,
NHTSA has adopted the proposed procedures tests with little change.
This section responds to the comments and explains NHTSA's reasons for
adopting the provisions set forth in this final rule. For the
convenience of readers, a list of the test specifications can be found
in appendix C to this final rule preamble.
This final rule adopts the two proposed false activation testing
scenarios--the steel trench plate test and the vehicle pass-through
scenario. Both tests are performed during daylight. Testing is
performed with manual brake application and without manual brake
application. The performance criterion is that the AEB system must not
engage the brakes to create a peak deceleration of more than 0.25 g
additional deceleration than any manual brake application would
generate (if used).
Comments
NHTSA received comments both supporting and opposing the proposed
false activation tests. Commenters in favor of including the tests in
FMVSS No. 127 include: Consumer Reports, Advocates, the Lidar
Coalition, AAA, Bosch, Porsche, and CAS. Consumer Reports states that
it is important to limit false activations to maximize safety and
consumer acceptance. AAA supported the steel trench plate test, stating
that it is important to ensure that increased system sensitivity does
not occur at the expense of unnecessary braking. CAS suggested the
addition of a third test involving a railroad crossing. The Lidar
Coalition stated that false positive tests are important for evaluating
both sensing modalities and perception systems, as well as the
interplay between both pieces of an effective AEB and PAEB system.
NHTSA also received comments opposing inclusion of one or both of
the tests. Volkswagen recommended eliminating the proposed false
activation tests from the rule, believing the tests have no comparable
real-world relevance. Luminar expressed similar concern about real-
world similarity.
Agency Response
After considering the comments, NHTSA has decided to maintain the
false positive testing scenarios for AEB proposed in the NPRM. The
proposed false activation tests establish only a baseline for system
functionality and are by no means comprehensive, nor sufficient to
eliminate susceptibility to false activations. However, the tests are a
means to establish at least a minimum threshold of performance in the
standard.
NHTSA expects that vehicle manufacturers will design AEB systems to
thoroughly address the potential for false activations.\147\ Previous
implementations of other technologies have shown that manufacturers
have a strong incentive to mitigate false positives. Vehicles that have
excessive false positive activations may pose an unreasonable risk to
safety and may be considered to have a safety-related defect. NHTSA
understands from industry comments to this rulemaking and others that
industry generally designs their systems to minimize false
activations.\148\
---------------------------------------------------------------------------

\147\ 88 FR 38632 at 38696.
\148\ In response to a 2022 NCAP Request for Comment, the
Alliance stated in their comments to the 2022 NCAP notice where
NHTSA requested comment on the inclusion of false positive tests in
NCAP the Alliance stated that vehicle manufacturers will optimize
their systems to minimize false positive activations for consumer
acceptance purposes, and thus such tests will not be necessary.
Similarly, in response to the same 2022 NCAP notice, Honda stated
that vehicle manufacturers must already account for false positives
when considering marketability and HMI. These comments are available
in this docket https://www.regulations.gov/document/NHTSA-2023-0020-0001.
---------------------------------------------------------------------------

Nonetheless, NHTSA is including the false activation tests in this
final rule because NHTSA has seen evidence of false activations in
those scenarios and because NHTSA expects that the scenario might be
particularly challenging for AEB systems. Thus, the agency does not
agree to remove or add additional test scenarios or conditions to the
test scenarios at this time. NHTSA is including the tests in FMVSS No.
127 to establish a reasonable minimum when it comes to false activation
assessment and mitigation; the agency may add to the tests in the
future if the need arises.
CR commented that a 0.25g deceleration threshold is too high,
stating that a ``0.25g braking event is noticeable by passengers and
could confuse or distract the driver.'' In response, the requirement is
for peak additional deceleration, not for average deceleration. In
other words, the deceleration that Consumer Reports is describing would
likely not meet the requirement. Consumer Reports is referring to a
brief, not sustained, brake pulse, which would be noticeable. The 0.25g
peak deceleration threshold was chosen as an obvious indication of
external braking that is easily measurable by testing equipment.
Bosch supported the proposed steel trench plate properties for the
steel trench plate test but suggested that the orientation of the plate
be accurately aligned within a tolerance, e.g., aligning the leading
edge of the plate 90 degrees plus or minus 0.5 degrees to the
centerline of the test vehicle.
In response, NHTSA does not agree with Bosch that a tolerance is
appropriate for positioning of the steel plate, particularly such a low
tolerance as 0.5 degrees. The steel plate false activation test is an
established test which has been performed without a specific tolerance
for the alignment of the steel plate for an extended period without any
indication that the lack of a tolerance influences the outcome of the
tests. Further, Bosch has not provided any data in support of their
suggestion, and NHTSA does not have any data suggesting that any slight
misalignment of the steel plate influences the results.
Porsche stated that they support the false positive tests with some
suggested improvements. Porsche stated that they suggest modifying the
pass-through test lateral distance gap in S9.3.1(b) to be in relation
to the exterior of the vehicle body instead of the front wheels.
Porsche also suggested adding a test matrix table to section S8.1.
Volkswagen suggested that NHTSA better define the test scenarios, such
as with regard to the exterior dimensions of the stationary vehicles in
the pass-through gap test and whether there is a manual brake
application in either test.
In response, while Porsche states that the gap between the vehicles
should be measured based on the exterior of the vehicles, not the
wheels, the commenter did not provide any data or reasoning for the
suggestion. Volkswagen suggests that more detail should be given on the
exterior dimensions of the stationary vehicles but also did not provide
any supporting data or reasoning. NHTSA had evaluated these
requirements when developing the NPRM and found them to be sufficient.
Accordingly, the agency is not revising how the space between the
vehicles is measured and how we specify the dimensions of the two
stationary vehicles.
Porsche and Volkswagens both state it is unclear whether testing is
to be done with and without manual brake application. In response,
NHTSA notes

[[Page 39754]]

that in the NPRM, NHTSA specifically states that it would test vehicles
with and without manual application. While the agency does not believe
a table is needed specifying the key parameters when testing for lead
vehicle and PAEB, NHTSA agrees that the proposed regulatory text was
not clear on this topic. Thus, the agency has revised the regulatory
text for the steel plate and for the pass-through test to be clear that
testing is conducted with manual brake application and without manual
brake application.

K. Track Testing Conditions

1. Environmental Test Conditions
Lighting Conditions
Under this final rule, NHTSA will test AEB systems in daylight for
lead vehicle AEB and PAEB testing, as well as in darkness for PAEB
testing. The light conditions ensure performance in a wide range of
ambient light conditions. For all daylight testing, the ambient
illumination at the test site is not less than 2,000 lux, which
approximates the minimum light level on a typical roadway on an
overcast day. To better ensure test repeatability, testing may not be
performed while the intended travel path is such that the heading angle
of the vehicle is less than 25 degrees with respect to the sun and
while the solar elevation angle is less than 15 degrees. The intensity
of low-angle sunlight can create sensor anomalies that may lead to
unrepeatable test results.
For PAEB darkness testing, the ambient illumination at the test
site must be no greater than 0.2 lux. This value approximates roadway
lighting in dark conditions without direct overhead lighting with
moonlight and low levels of indirect light from other sources. This
darkness level accounts for the effect ambient light has on AEB
performance, particularly for camera-based systems. It ensures robust
performance of all AEB systems, regardless of what types of sensors are
used.
Comments
NHTSA received several comments on the lighting conditions,\149\
particularly the proposed ambient illumination requirement (i.e., any
level at or below 0.2 lux) for darkness PAEB testing.
---------------------------------------------------------------------------

\149\ These commenters included HATCI, MEMA, Bosch, Mitsubishi,
and AAA.
---------------------------------------------------------------------------

HATCI and others believe that NHTSA should use nighttime lighting
conditions for PAEB testing that are more characteristic of urban
environments. HATCI states that NHTSA would use the same specification
for lower and upper beams, 0.2 lux, but that an ambient environment of
0.2 lux is extremely dark and is unlikely to be representative of real-
world conditions in an urban area. HATCI stated that since 82% of the
pedestrian fatalities occur in urban areas, these environmental
conditions should be reflected in the test procedures. HATCI suggests
that the agency should include overhead lights as it is more
representative of the urban environment. The commenters state that
additional lighting, including streetlights, would align lighting
conditions with Euro NCAP. In contrast, AAA believes NHTSA should
refrain from allowing testing under artificially bright overhead
lighting for PAEB system performance requirements in darkness
conditions.
Agency Response
After considering the comments submitted about the lighting
conditions, NHTSA has decided to adopt the proposed lighting conditions
for several reasons. First, the agency is finalizing the proposed
lighting conditions because they present the most challenging, but
practicable, lighting conditions for PAEB systems. Because they will be
able to meet the most challenging condition, PAEB will be able to
perform well in situations with more light, like roads that have
streetlights. Although NHTSA agrees with commenters that 0.2 lux may
not be representative of urban scenarios at night, the agency disagrees
with HATCI, MEMA, Bosch, and Mitsubishi that testing should be
conducted with lighting conditions that mimic urban areas. Testing in
dark conditions, below 0.2 lux, represents the worst lighting case,
where pedestrians are most at risk.\150\
---------------------------------------------------------------------------

\150\ For the proposed PAEB testing in darkness, the ambient
illumination at the test site must be no greater than 0.2 lux. This
value approximates roadway lighting in dark conditions without
direct overhead lighting with moonlight and low levels of indirect
light from other sources, such as reflected light from buildings and
signage.
---------------------------------------------------------------------------

Second, testing during daylight and dark with lower beams and upper
beams provides confidence that in urban dark lighted environments, PAEB
will perform even if the agency does not test under such a condition
In addition, the agency conducted confirmatory testing that
indicates that the proposed lighting conditions represented ambitious,
yet achievable conditions. The agency conducted additional research on
the performance of the AEB systems of six model year 2023 vehicles when
approaching a pedestrian. The darkness testing occurred with less than
0.2 lux of ambient lighting. In the scenario where the pedestrian is
approaching from the right, five of the six vehicles tested were able
to meet the performance requirements for the upper beam lighting
condition, and four of the six were able to meet the lower beam
lighting condition. In the scenario where the pedestrian is stationary,
all vehicles were able to meet the upper beam light condition, and
three of the six vehicles were able to meet the lower beam testing
condition. The final nighttime scenario, with the pedestrian moving
along the vehicle's path, four vehicles met the performance
requirements for the upper beam condition, and a single vehicle met the
lower beam condition. NHTSA believes that this data show that testing
with the ambient light below 0.2 lux is practicable. For the above
reasons, NHTSA believes the lighting conditions adopted by this final
rule best ensure that PAEB systems work in all environments where
pedestrians are at the highest safety risk.
As for the proposed PAEB daylight testing conditions, several
sensor suppliers suggested that the agency should reconsider the
sunlight glare avoidance requirement (i.e., not driving toward or away
from the sun--less than 25 degrees in vertical and 15 degrees in
horizontal directions). Adasky and the Lidar Coalition stated that the
NHTSA should include additional real world environmental conditions,
such as direct sunlight.
In response, the agency agrees with Luminar that there is a safety
issue on the road when drivers operate in direct sunlight. However, the
agency does not have enough test data to assess the statements from
manufacturers of lidar systems (Adasky, Luminar, The Lidar Coalition)
on the efficacy of LIDAR systems and potential sensor saturation by
testing in direct sunlight. Additionally, NHTSA believes that, if
research is warranted to assess the accuracy of the companies'
assertions, that would delay this rulemaking. Thus, NHTSA declines to
change the final rule as requested.
Ambient Temperature
This final rule adopts the proposed specification that the ambient
temperature in the test area be between 0 Celsius (32 [deg]F) and 40
Celsius (104 [deg]F) during AEB testing. This ambient temperature range
matches the range specified in NHTSA's safety standard for brake system
performance and is representative of the wide range of conditions that
AEB-equipped vehicles encounter. As explained in the NPRM,

[[Page 39755]]

while AEB controls and sensors can operate at lower temperatures, the
limiting factor here is the braking performance.
Comments
FCA commented that, given the only proposed outcome is ``no
contact'' and passing results in the research data are often less than
one meter, brake stopping performance and variation become crucial. FCA
stated that because of this, testing at temperature becomes a primary
concern. FCA suggested that if NHTSA believes braking performance at
hot temperatures is the worst case, it should make that explanatory
statement. However, if NHTSA believes braking is worst case at cold
temperatures, it should assess AEB performance at the freezing point
minimum temperature. Otherwise, it should limit the regulatory testing
to a much more modest range to accommodate the existing data.
Agency Response
In response, NHTSA notes that FCA did not provide the testing range
that it believes would be acceptable, or explain its concern about
aspects of the proposed range. NHTSA believes that braking performance
would be relatively unaffected by outside temperature because the
procedures specify that there will be an initial braking temperature
which ensures that the brakes are warm when tested, and has specified a
burnishing procedure to ensure that the brakes perform consistently.
The final rule specifies a testing range consistent with the ranges
included in the existing braking standards applying to the vehicles
subject to FMVSS No. 127. Those testing temperatures have worked well
in those braking standards, and NHTSA is unaware of information
indicating they would be unacceptable for this rule. Accordingly, NHTSA
adopts the ambient temperature range proposed in the NPRM without
change.
Wind Conditions
This final rule adopts the proposed specification that the maximum
wind speed during AEB compliance testing be no greater than 10 m/s (22
mph) for lead vehicle avoidance tests and 6.7 m/s (15 mph) for
pedestrian avoidance tests. Excessive wind during testing could disturb
the test devices in various ways. For example, high wind speeds could
affect the ability of the VTD to maintain consistent speed and/or
lateral position, or could while cause the pedestrian mannequin to bend
or sway unpredictably.
Comments
Bosch and Zoox are concerned with testing up to the proposed
maximum wind speed. Bosch states that the testing equipment is not able
to consistently maintain stability in windy conditions. Bosch and MEMA
suggest using language similar to UNECE R152 which specifies testing
only when there is no wind present that is liable to affect the
results. Zoox suggests reducing the maximum test wind speed from 10 m/s
to 5 m/s for all AEB testing.
Agency Response
NHTSA declines to adopt the suggested changes. The wind speeds
included in the proposal and adopted in this final rule have long been
used by the agency in AEB testing and testing of other systems in the
FMVSS. As stated in the NPRM, these are the same maximum wind speeds
specified for AEB tests in the agency's AEB NCAP test procedures and
PAEB draft research test procedure without problems. The wind speed
specified for lead vehicle avoidance tests is also in line with the
maximum wind speed specified for passenger vehicles in FMVSS No. 126,
``Electronic stability control systems for light vehicles.'' The
specification has been workable for many years.
Commenters did not explain the basis for characterizing the
proposed wind speeds as windy conditions, or what winds could affect
test results. They provided no information showing that the proposed
wind speeds would affect braking performance and test equipment
stability. NHTSA believes that the UNECE R152 approach would not be
helpful, as it is open-ended about wind speeds. It would not provide
manufacturers with notice of the wind speeds under which the agency
would test. NHTSA believes its approach of specifying the specific
range of wind speeds, as opposed to leaving it open ended and undefined
like UNECE R152, provides notice about the test conditions under which
compliance testing would be conducted and more assurance about what
NHTSA considers a valid test. The agency therefore adopts the
provisions for wind speed without change.
Precipitation
NHTSA adopts the proposed specification that NHTSA will not conduct
AEB compliance tests during periods of precipitation, including rain,
snow, sleet, or hail. The presence of precipitation could influence the
outcome of the tests because wet, icy, or snow-covered pavement has
lower friction. Conducting a test under those conditions also poses
risks to lab personnel. Additionally, the presence of precipitation
like rain, snow, sleet, or hail, makes it much more difficult to
reproduce a friction level with good precision. That is, even if NHTSA
were able to run a particular test on a pavement with precipitation,
replicating the same test conditions may not be possible.
Comments
Consumer Reports stated that the variation of AEB performance in
different conditions is why this additional testing is needed. It noted
that in its experience evaluating vehicles' wet-road braking
performance, it is feasible to establish objective test procedures for
conditions in which the ground is wet.
Agency Response
In response, NHTSA does not have the information necessary to
demonstrate that such testing would be possible for compliance testing.
NHTSA is encouraged that Consumer Reports conducts wet pavement testing
because such testing can add to the agency's knowledge in this area.
NHTSA encourages Consumer Reports to share more detailed information
about its wet-road braking to possibly provide a foundation for future
NHTSA research.
Visibility
This final rule adopts the proposed specification that AEB
performance tests will be conducted when visibility at the test site is
unaffected by fog, smoke, ash, or airborne particulate matter. Reduced
visibility in the presence of fog or other particulate matter is
difficult to reproduce in a manner that produces repeatable test
results. While NHTSA considered a minimum visibility range during the
development of the proposal, the agency proposed a limitation on the
presence of conditions that would obstruct visibility during AEB
testing. NHTSA sought comment on whether to adopt a minimum visibility
range.
Comments
ASC, ZF, and MEMA supported the proposed visibility conditions for
AEB testing. ASC, MEMA and ZF stated that defining minimum visibility
ranges would be challenging due to current sensor performance and
creating repeatable test conditions.
Other commentators requested a minimum visibility requirement and
gave suggestions on how to create a minimum visibility definition. The
Alliance stated that this should be objectively defined. Mobileye
suggests that a minimum level of visibility could

[[Page 39756]]

be defined as the visibility that allows a human driver to see the
target within 5 seconds time to collision. Bosch and FCA states that
NHTSA should establish a precise and comprehensive definition for
``visibility'' (e.g., that visibility will be greater than 1 km, 0.5
km, etc.). Bosch and Volkswagen state that the test must ensure that
the horizontal visibility range will allow the target to be clearly
observed throughout the test. Aptiv and Consumer Reports recommend
adding additional testing to account for real-world conditions such as
sun glare, rain, fog and smoke.
Agency Response
NHTSA adopts the provisions proposed in the NPRM without change,
for the reasons provided in the proposal. The agency agrees with
commenters that there may be merits to having an objective way to
measure visibility, but defining a minimum visibility range that is
objective is challenging, as noted by ASC, ZF, and MEMA. Bosch
suggested requiring visibility be measured as greater than ``X''
kilometers, similar to NCAP programs,\151\ and Mobileye suggested an
approach.
---------------------------------------------------------------------------

\151\ Euro NCAP specifies visibility of at least 1 km (0.62
miles) and NHTSA's NCAP specifies 5 km (3.1 miles).
---------------------------------------------------------------------------

NHTSA will further consider the pros and cons of these and other
approaches and determine whether to consider them in a future
rulemaking. For now, it does not appear that the commenters' requested
changes to the visibility metric proposed in the NPRM present a better
measurement than the limitation on the presence of conditions that
would obstruct visibility. Therefore, NHTSA will adopt the provisions
described in the NPRM.
2. Road/Test Track Conditions
Surface
This final rule adopts the proposed specification that NHTSA will
test on a dry, uniform, solid-paved surface with a peak friction
coefficient (PFC) of 1.02 when measured using an ASTM F2493 standard
reference test tire, in accordance with ASTM E1337-19 at a speed of
64.4 km/h (40 mph), without water delivery.\152\ Surface friction is a
critical factor in testing systems that rely heavily on brake system
performance testing, such as AEB. The presence of moisture will
significantly change the measured performance of a braking system. A
dry surface is more consistent and provides for greater test
repeatability.
---------------------------------------------------------------------------

\152\ ASTM E1337-19, Standard Test Method for Determining
Longitudinal Peak Braking Coefficient (PBC) of Paved Surfaces Using
Standard Reference Test Tire.
---------------------------------------------------------------------------

Comments
MEMA supports the test track surface having a peak friction
coefficient of 1.02. AAA recommended, based on previous testing, that
there should be some tolerance allowed in terms of peak friction
coefficient to allow for a greater number of closed-course facilities
to be suitable for confirmation testing. FCA asked for clarification,
as they see a maximum Roadway Friction Coefficient (RFC) but no mention
of any minimum RFC. In addition, FCA suggested adopting a similar
calculation for over speed/under speed tests within FMVSS No. 127 as in
FMVSS No. 135. The Alliance commented that NHTSA should define the
tolerance for the required test track surface with maximum and minimum
friction coefficients. It stated that such a tolerance would ensure
fairness when conducting tests across different test facilities, reduce
the cost/burden associated with maintaining a test surface having a
specific PFC, particularly since this value can change over time, and
is consistent with NCAP's Crash Avoidance test procedures.
Agency Response
NHTSA first addressed this issue in the final rule upgrading the
motorcycle brake system standard published in 2012.\153\ NHTSA stated
that, by specifying a single PFC, the intent is not to specify testing
only on surfaces with that PFC. Rather, the intent is to set a target
PFC that acts as a reference point. Manufacturers who choose to conduct
on-track testing to certify their vehicles can use test surfaces with
any PFC below the specified level to ensure compliance at the specified
level. On the other hand, NHTSA, and laboratories conducting compliance
tests, would use surfaces having a PFC at or above the target PFC to
allow a reasonable margin for friction variations and other test
surface variables.
---------------------------------------------------------------------------

\153\ 77 FR 51650 (Aug. 24, 2012).
---------------------------------------------------------------------------

This approach of specifying PFC without tolerance is consistent
with how surface peak friction coefficients are specified in FMVSS No.
121, ``Air Brake Systems,'' FMVSS No. 135, ``Light Vehicle Brake
Systems,'' and in FMVSS No. 126, ``Electronic Stability Control
Systems. FMVSS No. 126 mandates Electronic Stability Control (ESC)
systems on light vehicles, and establishes test procedures to ensure
that ESC systems meet minimum requirements. In the rulemaking that
established FMVSS No. 126, NHTSA originally proposed a tolerance around
the surface PFC specification, but ultimately specified a single PFC
for the test surface in the final rule. The agency explained that,
although the proposed tolerance was an attempt to increase objectivity,
such a tolerance created the possibility of compliance tests for FMVSS
No. 126 being performed on lower friction coefficient surfaces than
those for other braking standards, which is not the intention. NHTSA
explained that while it is unlikely that any facility has a surface
with exactly that friction coefficient, compliance testing for other
braking standards is performed on a surface with a PFC slightly higher
than the specification, which has more adhesion and creates a margin
for clear enforcement. Here, as in the ESC final rule, NHTSA will use
consistent compliance test conventions across all FMVSSs when
specifying surface PFC.
Slope
This final rule adopts the proposed specification that NHTSA's test
surface will have a consistent slope between 0 and 1 percent. The slope
of the road surface can affect the performance of an AEB-equipped
vehicle.\154\ The slope also influences the dynamics and layout
involved in the AEB test scenarios.
---------------------------------------------------------------------------

\154\ Kim, H. et al., Autonomous Emergency Braking Considering
Road Slope and Friction Coefficient, International Journal of
Automotive Technology, 19, 1013-1022 (2018).
---------------------------------------------------------------------------

Comments
MEMA and Bosch commented, suggesting language from FMVSS No. 135
stating that the test surface has no more than a 1% gradient in the
direction of testing and no more than a 2% gradient perpendicular to
the direction of testing.
Agency Response
In response, NHTSA has not made the requested change. The agency's
proposed specification did not specify that this is consistent in only
the direction of travel. The agency might test on a surface that is not
necessarily a defined lane, so, much like with ESC testing, the surface
could be 1% in the direction of travel or normal to the direction of
travel.
NHTSA provides the public with information on how the agency will
conduct compliance tests, but manufacturers are not required to certify
their vehicles using the tests in the FMVSS. Testing on a surface that
is less flat could be more stringent, and manufacturers are free to
test on a more stringent surface than what the agency

[[Page 39757]]

uses.\155\ Therefore, the agency does not see a need for the suggested
change.
---------------------------------------------------------------------------

\155\ The manufacturer must exercise due care in making its
certification. While manufacturers are not required to follow the
tests in the FMVSSs, manufacturers seek to ensure that their
vehicles will meet the FMVSS when NHTSA tests them according to the
test procedures in the FMVSSs.
---------------------------------------------------------------------------

Markings
This final rule adopts the proposed specification that, in NHTSA's
tests, within 2 m of the intended travel path, the road surface can be
unmarked, or marked with one, or two lines of any configuration or
color, at NHTSA's option. If lines are used, they must be straight,
and, in the case of two lines, they must be parallel to each other and
the distance between them must be from 2.7 m to 4.5 m. Vehicles
equipped with AEB often are equipped with other advanced driver
assistance systems, such as lane-centering technology, which detects
lane lines. Those systems may be triggered by the presence of road
markings, potentially leading to unrepeatable results.
Comments
In its comment, Bosch recommended including surface conditions such
as grade lane markings, surrounding clearance areas, and acceptable
target object specifications to enhance the accuracy and reliability of
the testing process in each scenario. Zoox recommended specific
markings for the regulation. It suggests text stating: ``The road
surface within 2 m of the intended travel path is marked with two solid
lines (yellow on the left, white on the right) that are straight,
parallel to each other, and at any distance from 2.7 m to 4.5m.'' Zoox
believes that, in the scenarios prescribed and with the variety of
permissible lane markings, an ADS may drive around the obstruction
instead of stopping in lane. It recommends specifying lane markings
consistent with the Manual on Uniform Traffic Control Devices (MUTCD).
Agency Response
NHTSA disagrees with the recommendation by Bosch and Zoox to change
the lane marking specifications for the compliance test. Fully marking
the lane would simulate a vehicle traveling on new, well-marked
roadways, which reduces the representativeness of test of the real-
world. Lane markings across the country vary in terms of existence,
quality, and placement. Many rural roads have little to no lane
markings, older roads may have degraded or missing lane markings, and
even new roadways may have lane markings that are not yet present. The
provision that states that NHTSA has flexibility in how the lanes are
marked puts manufacturers on notice that they must consider all roadway
types when designing their AEB system, not just road with newly marked
lines. The most commonly encountered lane marking colors are white and
yellow; however, there are areas where vehicles may encounter other
colors. The MUTCD states that markings are to be yellow, white, red,
blue, or purple. Less common situations include E-ZPass lanes that are
marked with purple/white lane markings. In general NHTSA does not
believe that lane markings/colors have a technical effect on AEB
performance, however specifying that lane lines used may be any color
ensures that AEB performance will not vary based on lane marking color
faded color.
NHTSA believes it is important to the real-world efficacy of AEB
systems that AEB be designed to consider a wide variety of lane
markings that it is reasonable to assume the systems may encounter in
the real world. NHTSA is concerned that reducing the types of lane
markings they need to consider would work against NHTSA's goals of
ensuring the robustness of AEB systems and the safety benefits AEB can
attain. Therefore, the agency will adopt the provisions described in
the NPRM without change.
Subject Vehicle Conditions
This final rule adopts the proposed specification about the subject
vehicle conditions during testing relating to the following topics: AEB
initialization, tires, subject vehicle brakes, fluids and propulsion
battery charge, user adjustable settings, headlamps and subject vehicle
loading. Where the agency received no comments a particular topic, it
is not discussed below. All proposals are adopted for the reasons
discussed in the NPRM.
AEB System State and Initialization
In the NPRM, NHTSA proposed that testing not be conducted if the
AEB malfunction telltale is illuminated or any of the sensors used by
the AEB systems are obstructed. NHTSA proposed that AEB systems would
be initialized before each series of performance tests to ensure the
AEB system is in a ready state for each test trial. This is because the
electronic components of an AEB system, including sensors and
processing modules, may require a brief interval following each
starting system cycle to reset to their default operating state. It
also may be necessary for an AEB-equipped vehicle to be driven at a
minimum speed for a period of time prior to testing so that the
electronic systems can self-calibrate to a default or baseline
condition, and/or for the AEB system to become active.
The proposed initialization procedure specifies that, once the test
vehicle starting system is cycled on, it will remain on for at least
one minute and the vehicle is driven at a forward speed of at least 10
km/h (6 mph) before any performance trials commence. This procedure
also ensures that no additional driver actions are needed for the AEB
system to be in a fully active state.
In its comment, Porsche suggested that vehicles should be brought
to operating temperature before testing is begun. NHTSA disagrees with
this suggestion for several reasons. First, it is NHTSA's position that
the AEB system should be functional regardless of the vehicle's
operating temperature because to choose otherwise could lead to
unnecessary and concerning real-world limitations. The agency believes
that specifying that the vehicle will be started and running for at
least one minute prior to test initiation is more than sufficient for
the manufacturer to have a functional AEB system. In the real world,
vehicles often travel at the speeds proposed shortly after the driver
powers the vehicle on. NHTSA requires brakes, lights, and
crashworthiness devices, like seat belts and air bags, to work when the
vehicle is turned on. In the same manner, the vehicle must meet FMVSS
No. 127 when turned on. NHTSA is providing a brief initiation state for
the AEB system to reset to a default operating state, but extending
that state to the period suggested by Porsche would be contrary to the
need for safety.
NHTSA believes the one-minute initiation period is generous in the
context of the FMVSSs. There is a risk that drivers will not wait a
minute to start driving. These drivers likely expect all vehicle
system, especially safety systems, to be ready to operate once the
vehicle is turned on. Porsche did not provide sufficient justification
for its suggestion to extend that time. Based on these the above
factors, NHTSA is not accepting Porsche's suggestion.
MEMA, Volkswagen, Porsche, and Bosch commented that the agency
should adopt the pre-test conditioning process from UNECE Regulation
No. 152 where, if requested by the manufacturer, the vehicle can be
driven a maximum of 100 km (62.1 miles) to initialize the sensor
system.
NHTSA also disagrees with this suggestion for the reasons discussed
in the previous paragraph. This suggestion

[[Page 39758]]

presents issues similar to those flagged in the previous paragraph,
namely that the system should be available and functioning as soon as
possible after vehicle start up and that a failure to do that could be
very confusing to drivers and result in a failure to provide the safety
benefits it should. For the reasons explained in this section, this
final rule adopts the provisions proposed in the NPRM without change.
Brake Burnishing
To maximize test repeatability, this final rule adopts the proposed
specification that subject vehicle brakes be burnished prior to AEB
performance testing according to the specifications of either S7.1 of
FMVSS No. 135, Light vehicle brake systems, which applies to passenger
vehicles with GVWR of 3,500 kilograms or less, or to the specifications
of S7.4 of FMVSS No. 105, which applies to passenger vehicles with GVWR
greater than 3,500 kilograms. Since AEB capability relies upon the
function of the service brakes on a vehicle, it is reasonable and
logical that the same pre-test conditioning procedures that apply to
service brake performance evaluations should also apply to AEB system
performance evaluations.
Comments
In comments, MEMA, Volkswagen, Porsche, and Bosch suggest that the
agency adopt the pre-test conditioning process from UNECE Regulation
No. 152 in that the vehicle can undergo a series of brake activations
to burnish the brake system.
Agency Response
In response, NHTSA agrees with commenters that properly burnishing
the brake system is important, but NHTSA does not believe that it must
adopt this aspect of UNECE Regulation No. 152 to accomplish that. NHTSA
believes that the proposed brake burnishing procedures that are
consistent with both FMVSS No. 135 and FMVSS No. 105 properly burnish
the brake system, depending on the test vehicle's GVWR. Additionally,
commenters did not provide NHTSA with any evidence that the brake
burnishing procedures the agency proposed are improper for burnishing
brakes or are otherwise unacceptable for any reason. NHTSA is not
adopting the changes and will adopt the provisions proposed in the NPRM
without change.
Brake Temperature
This final rule adopts the proposed specification that the subject
vehicle service brakes be maintained at an average temperature between
65[deg] C (149 [deg]F) and 100[deg] C (212 [deg]F) measured as an
average of the brakes on the hottest axle. This temperature range,
which is the same as the range specified in FMVSS No. 135, is important
for consistent brake performance and test repeatability.
Comments
In comments, MEMA, Volkswagen, Porsche, and Bosch suggest that
NHTSA adopt the pre-test conditioning process from UNECE Regulation No.
152, specifically, that the average temperature of the service brakes
on the hottest axle should be between 65-100 degrees C prior to each
test run. Zoox also recommends that the hottest axle on the service
brakes should be between 65-100 degrees C prior to testing, and that
the agency should use FMVSS No. 135 as a guide for warming the vehicle
brakes.
Agency Response
In response, NHTSA points out that the commenters refer to initial
brake temperatures tested according to the procedure in FMVSS No. 135,
and appear to be supporting NHTSA's proposed provisions notwithstanding
reference to UNECE Regulation No. 152. The procedure in FMVSS No. 135
more rigorously specifies how and where temperature is measured than
the equivalent in UNECE Regulation No. 152. NHTSA concurs and is
adopting the provisions as proposed in the NPRM
User Adjustable Settings
This final rule adopts the proposed specification that NHTSA may
test user adjustable settings such as engine braking, regenerative
braking, and those associated with FCW, at any available setting state.
Furthermore, adaptive and traditional cruise control may be used in any
selectable setting during testing. The agency may test vehicles with
any cruise control or adaptive cruise control setting to make sure that
these systems do not disrupt the ability of the AEB system to stop the
vehicle in crash imminent situations. However, for vehicles that have
an ESC off switch, NHTSA will keep ESC engaged for the duration of the
test.
Comments
In its comments, HATCI stated that NHTSA should test the vehicles
using the default settings to represent real-world driving conditions
because HATCI's research indicates that consumers do not typically
change the settings. Bosch commented that the regenerative brakes add
too much variability to the vehicle performance. Therefore, Bosch
stated that the regenerative braking feature of a car, if equipped with
one, should be overridden for the duration of AEB testing. AAA
expressed concern that the proposal to allow vehicle testing with any
cruise control setting would introduce too many variables into the
testing scenario. AAA recommended the agency test all vehicles with the
latest AEB setting and/or test all vehicles with and without the cruise
control activated.
Agency Response
The purpose of the ``any'' user adjustable parameter is to ensure
that driver-activated settings do not negatively impact AEB
performance. NHTSA seeks to avoid a situation where use of a setting
reduces the requisite performance of AEB when tested according to the
parameters of S7, S8, and S9. NHTSA also sought to incorporate the word
``any'' into the standard to make clear that NHTSA has wide latitude to
adjust the settings in a compliance test, in accordance with 49 CFR
571.4. That section states: ``The word any, used in connection with a
range of values or set of items in the requirements, conditions, and
procedures of the standards or regulations in this chapter, means
generally the totality of the items or values, any one of which may be
selected by the Administration for testing, except where clearly
specified otherwise.''
NHTSA did not receive any comments indicating that the agency's
approach to ensure AEB performance would be problematic. Vehicle
manufacturers will have to assure that their designs do not negative
affect the performance of AEB and may have more of a certification
burden to assure such performance. The burden is reasonable, though, to
assure that AEB systems work properly when other systems are engaged.
Therefore, the agency is adopting the provisions proposed in the NPRM
without change.
Loading
This final rule adopts the proposed specification that NHTSA will
load the subject vehicle with not more than 277 kg (611 lbs.), which
includes the sum of any vehicle occupants and any test equipment and
instrumentation. The agency proposed this specification for load
because tests of the fully loaded vehicles are already required and
conducted under exiting FMVSSs, such as FMVSS No. 135, ``Light vehicle
brake systems,'' to measure the maximum brake capacity of a vehicle.

[[Page 39759]]

Comments
NHTSA received comments from MEMA and ASC recommending that the
agency harmonize with procedures of UNECE R151 and R152, and Euro NCAP.
Those procedures specify a maximum load of 200 kg.
Agency Response
In response, NHTSA declines to adopt the suggested change. NHTSA
derives the subject vehicle load of 277 kg (611 lbs.) from agency
testing, which uses the provision in NHTSA's NCAP test procedures.
Most, if not all, vehicle manufacturers are familiar with NCAP's
procedures and have designed their vehicles in accordance with them. As
explained in the NPRM, the stopping performance of a fully loaded
vehicle is already assessed under FMVSS No. 135. Commenters supporting
the UN Regulations maximum load of 200 kg gave little technical support
or rationale as to why that maximum load was preferred to the 277 kg
proposed load. It is not apparent to NHTSA whether or the degree to
which the 77 kg difference would change the test results. Therefore,
given the information available to the agency, NHTSA is adopting the
proposal.

L. Vehicle Test Device

This final rule adopts specifications for a VTD to be used for
compliance testing for the lead vehicle requirements. The GVT is a
full-sized harmonized surrogate vehicle developed to test crash
avoidance systems. To ensure repeatable and reproducible testing that
reflects how a subject vehicle would be expected to respond to an
actual vehicle in the real world, the VTD specified in this final rule
will be used as a lead vehicle, pass through vehicle, and obstructing
vehicle during testing. This final rule adopts all the specifications
in the NPRM.
This final rule specifies that the vehicle test device is based on
certain specifications defined in ISO 19206-3:2021, ``Road vehicles-
Test devices for target vehicles, vulnerable road users and other
objects, for assessment of active safety functions--Part 3:
Requirements for passenger vehicle 3D targets.'' \156\ The vehicle test
device is a tool that NHTSA will use in compliance tests to measure the
performance of AEB systems required by FMVSS No. 127.
---------------------------------------------------------------------------

\156\ https://www.iso.org/standard/70133.html. May 2021.
---------------------------------------------------------------------------

1. General Description
In the NPRM, NHTSA provided background on the agency's purpose and
rationale for proposing the VTD.\157\ The VTD provides a sensor
representation of a passenger motor vehicle. The rear view of the
vehicle test device contains representations of the vehicle silhouette,
a rear window, a high-mounted stop lamp, two taillamps, a rear license
plate, two rear reflex reflectors, and two tires.
---------------------------------------------------------------------------

\157\ 88 FR 38632 at 38705.
---------------------------------------------------------------------------

NHTSA received several comments on the proposed test device, all of
which were generally supportive. Bosch, AAA, Rivian, the Alliance, and
Ford all generally supported use of the proposed GVT across all AEB
systems. AAA stated that the GVT is easy to use and provides
versatility that allows for the evaluation of many realistic vehicle
interaction. Rivian recommended NHTSA align the GVT device with the
device used by Euro NCAP.
Forensic Rock, on the other hand, recommends higher speed targets
that can withstand high closing speed tests with minimal damage to the
vehicles. In response, NHTSA will continuously monitor the development
of AEB technologies and test devices associated with system
performance. If a need arises for new test devices, NHTSA can assess
and respond to the situation at that time.
2. Definitions
The proposal defined a ``vehicle test device'' as a test device
that simulates a passenger vehicle for the purpose of testing AEB
system performance and defined a vehicle test device carrier as a
movable platform on which a lead vehicle test device may be attached
during compliance testing.
Bosch recommended the definition of ``vehicle test device'' be
changed to ``a test device with the appearance and radar
characteristics that, together with the vehicle test device carrier,
simulates a passenger vehicle for the purpose of testing automatic
emergency brake system performance.''
In response, NHTSA has considered the difference in the proposed
definition for the ``vehicle test device'' and the definition suggested
by Bosch and believes there to be no utility difference. The definition
suggested by Bosch contains two areas of distinction from that of the
proposed rule. First, Bosch suggested adding the phrase ``with the
appearance and radar characteristics.'' While the specifications
contain appearance and radar characteristics, such details are not
needed within the definition to fulfill the purpose of a definition,
which is to provide clarity as to what items are included and excluded
from the term. The agency has decided to keep the definition broad and
specify the technical details in the body of the regulation.
Second, the definition suggested by Bosch provides that only the
combination of the vehicle test device and the vehicle test device
carrier represent a passenger vehicle. While the specifications provide
details of the carrier device, those details are minimal and are
primarily designed to minimize the carrier's appearances. One
limitation of Bosch's suggestion would be that only the combination of
the vehicle test device and the carrier would be usable for testing at
a definition level. Not all tests require movement of the vehicle test
device and as such, these tests could be conducted without a carrier
(provided that the vehicle test device meet the specifications without
the carrier). Considering that the appearance of the carrier is to be
minimal, such flexibility of testing provides advantages for compliance
testing. Accordingly, the agency is finalizing the definition of
vehicle test device as proposed in the NPRM.
3. Sideview Specification
NHTSA proposed to establish specifications applicable to only the
rear-end of the vehicle test device. The proposal sought comment on
whether the specifications for the vehicle test device should include
sides of the vehicle, as well as the rear-end, and proposed potentially
including the specifications from ISO 19206-3:2021.
Comments
Advocates, MEMA, ZF, and Bosch all support specification of
sideview, so the AEB can address cross traffic in the future. MEMA and
ZF also recommend angled rear view (30 degrees, for example)
representing a vehicle making a right-hand turn. Advocates suggested
that any shortcomings established with specifications of rear view
should also be addressed by NHTSA for side view. Bosch stated that for
test cases in which the sides of the vehicle are within the signal
detection of the radars and/or sensors, the sides need to be included.
Agency Response
In response, NHTSA is not adopting turning scenarios or other
scenarios where the side of the vehicle test device is critical to the
outcome of the test. All lead vehicle scenarios, with the single
exception of the false activation pass-through test, align the subject
vehicle with the vehicle test device longitudinally along each
centerline. Similar to the pass-through test, the obstructed pedestrian
test that utilizes the vehicle test device aligns the subject

[[Page 39760]]

vehicle with vehicle test device longitudinally, with offsetting
centerlines. Thus, no tests finalized in this final rule are dependent
on the side view characteristics of the vehicle test device. If, in the
future, tests are added that include side view interactions, the agency
will consider additional specifications to the vehicle test device. For
this final rule, the agency has finalized the rear-view characteristics
only and has not added any view characteristics other than 180 degrees.
4. Field Verification Procedure
The NPRM did not specify in-the-field verifications be performed to
assess whether the radar cross section falls within the acceptability
corridor throughout the life of the device. NHTSA sought comment
regarding the adoption of the optional field verification procedure
provided in ISO 19206-3:2021, Annex E, Section E.3.
Comments
Bosch commented in support of the utilization of the optimal field
verification procedure provided in ISO 19206-3:2021, Annex E, Section
E.3, and further suggests the inclusion of suitable parts of the Annex
C.
Agency Response
In response, the field verification procedure is not included in
this final rule. NHTSA testing has shown that the radar cross section
of a new GVT and a ``used'' GVT manufactured by at least one company
fall consistently within the specified corridor incorporated by
reference from ISO 19206-3:2021.\158\ The field verification procedure
alone does not fully demonstrate that the vehicle test device is within
the specifications outlined in this rule. Accordingly, while the agency
may informally use the field verification test to provide a general
indication of the state of the vehicle test device, such a procedure is
not appropriate for the test procedure.
---------------------------------------------------------------------------

\158\ Assessing the Effect of Wear on Vehicle Test Device Radar
Return Characteristics, available in the docket for this final rule
(NHTSA-2023-0021).
---------------------------------------------------------------------------

5. Dimensional Specification
NHTSA proposed that the rear silhouette and the rear window be
symmetrical about a shared vertical centerline and that representations
of the taillamps, rear reflex reflectors, and tires also be symmetrical
about the surrogate's centerline. Further, the license plate
representation was proposed to have a width of 300 15 mm
and a height of 150 15 mm, and be mounted with a license
plate holder angle within the range described in 49 CFR 571.108,
S6.6.3.1. Lastly, NHTSA proposed that the VTD representations be
located within the minimum and maximum measurement values specified in
columns 3 and 4 of Table A.4 of ISO 19206-3:2021 Annex A. The tire
representations are to be located within the minimum and maximum
measurement values specified in columns 3 and 4 of Table A.3 of ISO
19206-3:2021 Annex A. Additional clarification of terms was included in
the NPRM stating that ``rear light'' means ``taillamp,''
``retroreflector'' means ``reflex reflector,'' and ``high centre
taillight'' means ``high-mounted stop lamp.''
Comments
In their comments, Ford, Porsche, and FCA all agree with NHTSA that
the vehicle test device should be based on specifications defined in
ISO 19206-3:2021. AAA and Adasky, alternatively, suggests that NHTSA
re-assess the proposed requirement to be consistent with subcompact and
compact cars, given the increased popularity of larger crossovers,
SUVs, and light-duty trucks. Adasky recommends that the influences of
hood height and A-pillar be included in the vehicle test device
property definition.
Agency Response
In response, NHTSA has adopted the specification as proposed. Most
commentors agreed with the use of ISO 19206-3:2021, which NHTSA
proposed as appropriate in the NPRM. The agency does not have
information to support adopting a change at this time. The agency would
also point out that including the hood height and A pillar is
unnecessary for front to rear crashes because they are not visible from
the rear of the test device, which is the orientation for all tests.
6. Visual and Near Infrared Specification
NHTSA proposed that the vehicle test device rear representation
colors be within the ranges specified in Tables B.2 and B.3 of ISO
19206-3:2021 Annex B. The proposal also specified that the infrared
properties of the vehicle test device be within the ranges specified in
Table B.1 of ISO 19206-3:2021 Annex B for wavelengths of 850 to 950 nm
when measured according to the calibration and measurement setup
specified in paragraph B.3 of ISO 19206-3:2021 Annex B. Lastly, NHTSA
proposed that the rear reflex reflectors, and at least 50 cm\2\ of the
taillamp representations, of the vehicle test device be grade DOT-C2
reflective sheeting as specified in 49 CFR 571.108, S8.2.
NHTSA received no comments on this proposal. The agency has adopted
the provision for the reasons provided in the NPRM.
7. Radar Reflectivity
NHTSA proposed that the radar cross section of the vehicle test
device is to be measured while attached to the carrier (robotic
platform). NHTSA also proposed that the radar reflectivity of the
carrier platform be less than 0 dBm\2\ for a viewing angle of 180
degrees at a distance of 5 to 100 m, when measured according to the
radar measurement procedure specified in C.3 of ISO 19206-3:2021 Annex
C for fixed-angle scans. The proposal also stated that the rear bumper
area, as shown in Table C.1 of ISO 19206-3:2021 Annex C, contributes to
the target radar cross section. NHTSA proposed that the radar cross
section be assessed using a radar sensor that operates at 76 to 81 GHz
and has a range of at least 5 to 100 m, a range gate length smaller
than 0.6 m, a horizontal field of view of 10 degrees or more (-3dB
amplitude limit), and an elevation field of view of 5 degrees or more
(-3dB amplitude). The proposal stated that a minimum of 92 percent of
the filtered data points of the surrogate radar cross section for the
fixed vehicle angle, variable range measurements be within the radar
cross section boundaries defined in Section C.2.2.4 of ISO 19206-3:2021
Annex C for a viewing angle of 180 degrees when measured according to
the radar measurement procedure specified in C.3 of ISO 19206-3:2021
Annex C for fixed-angle scans. Lastly, the proposed rule stated that
between 86 to 95 percent of the vehicle test device spatial radar cross
section reflective power be within the primary reflection region
defined in Section C.2.2.5 of ISO 19206-3:2021 Annex C, when measured
according to the radar measurement procedure specified in Section C.3
of ISO 19206-3:2021 Annex C using the angle-penetration method.
Comments
In their comments, ZF and ASC both consider the tolerance of +/-
10dBm\2\ to be quite high. ZF noted that information derived might be
misleading (e.g., object classification). In addition, ZF, ASC,
Mobileye, and MEMA recommend including acceptable Radar Cross Section
(RCS) ranges for the rear and the side of the VTD. While ZF, ASC, and
MEMA suggest using the same RCS corridor values as specified in ISO
19206-3:2021, Mobileye suggests setting the bars at the lower RCS
values (e.g., -10dBsm for VRU, 0dBsm or below for

[[Page 39761]]

motorcycle). Mobileye also suggests including lateral edge errors as
critical metrics because identifying the lateral edges of the object
lowers risk of false association with camera or other sensors. Bosch
recommends amending the radar reflectivity specifications because,
``The radar reflectivity of the carrier platform alone is less than 0
dBm\2\ for a viewing angle of 180 degrees and over a range of 5 to 100
m when measured according to the radar measurement procedure specified
in Section C.3 of ISO 19206-3:2021 Annex C for fixed-angle scans.''
Agency Response
The agency disagrees with the suggested revision to the radar
reflectivity for the carrier, as the carrier radar characteristics are
important when attached to the VTD, not the carrier by itself for the
purposes of testing AEB. Testing the carrier alone fails to take into
account the actual interface between the VTD and the carrier system.
Regarding the RCS range, the agency believes that both values are
needed to set appropriate bounds of what is acceptable RCS for the VTD
to match real world vehicles. The vehicle tests using two different
sensors documented in the ISO 19206-3:2021 Figure C.17 and C.18 show
that the vehicles tested varied within +/- 10dBm\2\. Thus, permitting
the vehicle test device to vary within this tolerance provides real-
world application for the various vehicles on the road. In addition,
lateral error tolerances are included in the test set-up
specifications.
NHTSA is not adding turning scenarios to this proposal, and
therefore the agency believes that side presentation specifications are
not needed. NHTSA is finalizing the radar reflectivity specifications
for the vehicle test device as proposed in the NPRM.
8. List of Actual Vehicles
In addition to the vehicle test device specifications, NHTSA sought
comment on specifying a set of real vehicles to be used as vehicle test
devices in AEB testing. NHTSA also sought comment on the utility and
feasibility of safely conducting AEB tests with real vehicles, such as
through removing humans from test vehicles and automating scenario
execution, and how laboratories would adjust testing costs to factor in
the risk of damaged vehicles. Additionally, NHTSA sought comments on
the merits and potential need for testing using real vehicles, in
addition to using a vehicle test device, as well as challenges,
limitations, and incremental costs of such.
Comments
Advocates and Bosch both generally support the development of a
list of possible real vehicles that could be used for testing in
addition to the GVT. While Bosch suggests that NHTSA reference the
relevant parts of ISO 19206-3:2021 if using a set of real vehicles,
Advocates recommend that NHTSA consider the most frequently registered
vehicles in the US over some lookback period with an established
timeline.
In contrast, Rivian, Alliance, ASC, ZF, and MEMA all oppose using
real vehicles. ZF, MEMA, and ASC state high cost and risk of injury to
human subjects in performing high-speed AEB tests. ASC and ZF added
that the advantages of testing with real vehicles compared to soft
vehicle targets is not clear. Furthermore, ZF and MEMA mention that the
tests that involve a soft target could serve as a real vehicle test if
combined with documentation provided by the OEM.
The Alliance notes test repeatability and reproducibility
challenges due to potential differences in vehicles selected for
testing and that repairs may be expensive and time-consuming if contact
occurs. It also notes that the current GVT is correlated to real world
vehicles through collaborative global government/industry testing and
verification. Rivian stated that using representative test devices, as
opposed to real vehicles, reduces test burdens on manufacturers and
poses lesser risk of injury if AEB fails to avoid a crash during the
test procedure. ASC and ZF believe that vehicles with AEB systems
should be able to detect a wide range of vehicles and suggests that if
NHTSA decides to develop its own, more US-fleet representative GVT
target, then it should be compliant with the ISO standard.
Agency Response
NHTSA agrees that the VTD specifications provide sufficient
flexibility in appearance that creating a list of vehicles for testing
is not likely to increase the safety impacts of the rule. NHTSA also
agrees that there are concerns over the cost of testing with real
vehicles, and, that there are potential safety risks to test operators.
NHTSA believes that the GVT is representative of a genuine
vehicle,\159\ and does not believe that the increased costs of adding a
documentation requirement for manufacturers to show this is warranted
at this time. Accordingly, the agency is not adopting a list of real
vehicles for testing at this time.
---------------------------------------------------------------------------

\159\ Overall, the AEB system sensors interpret the SSV appears
to sensors as a genuine vehicle. Nearly all vehicle manufacturers
and many suppliers have assessed how the SSV appears to the sensors
used for their AEB systems. The results of these scans have been
very favorable. 80 FR 68615, NCAP RFC, Docket No. NHTSA-2015-0006.
---------------------------------------------------------------------------

M. Pedestrian Test Devices

This final rule adopts specifications for two pedestrian test
devices to be used for compliance testing for the PAEB requirements.
The two pedestrian test devices each consist of a test mannequin and a
motion apparatus (carrier system) that positions the test mannequin
during a test. NHTSA's specifications for pedestrian test mannequins
represent a 50th percentile adult male and a 6- to 7-year-old child.
NHTSA has incorporated by reference specifications from three ISO
standards.
1. General Description
The Adult Pedestrian Test Mannequin (APTM) provides a sensor
representation of a 50th percentile adult male and consists of a head,
torso, two arms and hands, and two legs and feet. The Child Pedestrian
Test Mannequin (CPTM) provides a sensor representation of a 6- to 7-
year-old child and consists of a head, torso, two arms and hands, and
two legs and feet. The arms of both test mannequins are posable but
will not move during testing. The legs of the test mannequins will
articulate and will be synchronized to the forward motion of the
mannequin.
In the NPRM, NHTSA provided background on the agency's purpose and
rationale for proposing the test devices and the history of the devices
and their use,\160\ including previous NHTSA Federal Register notices
that have solicited input from the public on test procedures that
include the use of these pedestrian test devices either in current or
past form (i.e., articulated vs. non-articulated legs).
---------------------------------------------------------------------------

\160\ 88 FR at 38702.
---------------------------------------------------------------------------

NHTSA received many comments on the proposal, all of which were
generally supportive. Commenters generally supported the use of the ISO
19206-2:2018 mannequins as these are already validated and readily
available. SAE noted that its mannequin prototypes had limited testing
in the test track and deferred to NHTSA's understanding of the new
standard to know which pedestrian mannequin would be most appropriate
for the regulation. The commenters also supported harmonizing with
international standards, such as UNECE Regulation No. 152, as a
baseline for mannequin specifications, and with ISO

[[Page 39762]]

19206-2:2018 regarding the PAEB mannequins.
In response, NHTSA is adopting the relevant parts of ISO 19206-
2:2018 and ISO 19206-4:2020, as specified in the NPRM. ISO 19206 has a
larger body of research testing to support its test devices than SAE
J3116, and using ISO 19206 is consistent with international standards
like UNECE Regulation No. 152.
For the mannequin carrier system, Bosch suggested adoption of the
ISO 19206-7 specifications and test hardware to specify the carrier
system used to move the pedestrian test mannequin. Bosch further
recommended revising the definitions of the adult and child mannequins
to refer to the carrier systems. NHTSA is declining to make these
changes. Because ISO 19206-7 is still in draft form, NHTSA believes it
is premature to consider it for adoption. Regarding the carrier system,
it is a modular system designed to move the child and adult test
mannequins. As such, NHTSA believes that the definition of the carrier
system should lie outside the definition of either mannequin. It is
also more appropriate to specify how the carrier system can affect
sensor representations of the mannequins, rather than specify it as
part of a mannequin.
The American Foundation for Blind (AFB) recommended NHTSA use the
most inclusive and effective mannequins that will reduce road injuries
and deaths among people with disabilities, including women, adults with
short stature, and cyclists. Some commenters suggest that NHTSA use
pedestrian test mannequins using mobility assistive devices, such as
wheelchairs (motorized and non-motorized), walkers, motorized scooters,
or canes.
In response, NHTSA is interested in additional pedestrian test
devices outside of the child and adult pedestrian test mannequins,
including those that reflect the broad diversity among the American
public. At this time, however, there is a need for more development,
research, and testing for pedestrian test mannequins that are using
mobility assistive devices. NHTSA intends to monitor the progress of
these devices as they are developed and standardized, for possible
inclusion in the standard at a future date.
2. Dimensions and Posture
The APTM and the CPTM have basic body dimensions and proportions
specified in ISO 19206-2:2018. All commenters responding to the
proposed dimensions agreed with the proposal. The agency is adopting
the proposal for the reasons provided in the NPRM.
A number of commenters responded to NHTSA's question asking whether
use of the 50th percentile adult male test mannequin would ensure PAEB
systems will react to small adult females and other pedestrians other
than mid-size adult males. Consumer Reports (CR) supported NHTSA's
proposal to use a pedestrian test mannequin representing a 50th-
percentile adult male and one representing a six- to seven-year-old
child, stating it is critical to use both mannequins in PAEB testing to
account for a range of human proportions. The commenter believed it is
especially important to use the child mannequin to provide adequate
protection for children and other shorter individuals, particularly
from impacts involving large vehicles that have tall hoods or that
otherwise have limited frontal visibility.
Several commenters (Advocates, AARP, ZF, Consumer Reports, and
MEMA) suggested including an adult female mannequin and the child
mannequin in all tests. NHTSA is unaware of any standards providing
specifications for a 5th percentile adult female test mannequin, or of
any consumer information programs testing with such a device.
The Alliance stated that the proposed child and adult test devices
should provide a reasonable assessment across a broad spectrum of
occupant sizes.\161\ AAA recommended not including the child test
mannequin for all testing scenarios, as this would increase testing
burdens. AAA suggested that, as an alternative, NHTSA could test some
scenarios with the smaller SAE pedestrian test mannequin.
---------------------------------------------------------------------------

\161\ The Alliance supported using a child test mannequin in
daytime scenarios only, and not also in the nighttime scenario.
NHTSA discussed this comment in separate section.
---------------------------------------------------------------------------

After reviewing the comments, NHTSA is satisfied that the currently
proposed pedestrian test mannequins provide a reasonable representation
of the pedestrian crash population for purposes of issuing this final
rule. In its comment to the NPRM, IIHS stated that evidence does not
demonstrate that current PAEB systems are tuned only to the adult male
mannequin. This rulemaking does not expand the mannequins used in new
FMVSS No. 127, or expand how the child dummy is used, because NHTSA
does not have the body of research necessary to support such changes
for this final rule.
FCA noted that there are no dimensional tolerances on the
pedestrian test device. In response, NHTSA's testing has not shown an
issue with the dimensions specified in the NPRM. Further, the
locational bounds of the pedestrian test mannequin are specified in the
individual test scenarios. Thus, the agency is not adopting additional
tolerances on the dimensional specification of the pedestrian test
mannequins. SAE responded to NHTSA's comment on shoe height, stating
that the overall mannequin height on the sled is representative of the
overall height of real pedestrians with shoes.
3. Visual Properties
The mannequins will have specified features for the depictions of
hair, skin tone, clothing, and the like. The features are specified in
the ISO standards incorporated by reference into FMVSS No. 127 by this
final rule. The incorporated ISO standards provide needed
specifications for these features, but they also allow NHTSA to
harmonize with specifications for test mannequins in use by Euro NCAP.
Because specifications for test mannequin skin color are not found
in ISO 19206-2:2018, NHTSA is incorporating by reference the bicyclist
mannequin specifications for color and reflectivity found in ISO 19206-
4:2020, ``Road vehicles--test devices for target vehicles, vulnerable
road users and other objects, for assessment of active safety
functions--Part 4: Requirements for bicyclists targets.'' Although this
standard provides requirements for bicyclist test devices, NHTSA is
referencing it for color and reflectivity for the prescribed adult and
child test mannequins because the specifications are workable for use
with the ISO standard for pedestrian test devices. NHTSA is specifying
that the test mannequins be of a color that matches a specified range
of skin colors representative of very dark to very light complexions.
The mannequins must also have standardized properties that represent
hair, facial skin, hands, and other features, and must have a
standardized long-sleeve black shirt, blue long pants, and black shoes.
Commenters (AARP, Safe Kids Worldwide (SKW), Safe Kids in
Autonomous Vehicles Alliance (SKAVA), Luminar, and private citizens)
supported NHTSA's effort to ensure PAEB detect pedestrians of all skin
colors. The agency agrees with the commentors that sensors should
detect skin tones other than light skin tones.
Luminar did not support the white face, black shirt, and blue pants
on mannequins. While NHTSA understands that the commenter would like to
see testing outside of the

[[Page 39763]]

specifications identified in the NPRM, the agency does not have the
body of knowledge necessary to objectively specify clothing outside of
the black shirt and blue pants. Furthermore, commenters did not provide
data demonstrating that current PAEB systems do not already detect a
wide array of skin tones. The proposal includes a range of colors
(based on ISO 19206-4_2020 standard) for skin, face, and hands. NHTSA
encourages manufacturers to consider designing their systems to detect
all pedestrians, including those wearing various clothing colors.
4. Radar Properties
The radar reflectivity characteristics of the pedestrian test
device approximates that of a pedestrian of the same size when
approached from the side or from behind. Radar cross section
measurements of the pedestrian test mannequins must fall within the
upper and lower boundaries shown in Annex B, section B.3, figure B.6 of
ISO 19206-2:2018 when tested in accordance with the measure procedure
in Annex C, section C.3 of ISO 19206-2:2018.
In response to Bosch, this final rule adopts the newer ISO 19206-
3:2021 instead of ISO 19206-2:2018 in determining the upper and lower
boundaries for an object for radar cross-section measurements. The
proposed procedure in Annex C, section C.3 of ISO 19206-2:2018 is
specific for pedestrian targets; however, recent testing performed by
the agency indicates that the three position measurement specified in
Annex C, section C.3 of ISO 19206-3:2021 provides more reduction in
multi-path reflections and offers more accurate radar cross section
values. This testing confirms the recommendation from Bosch to adopt
the measurement procedure in Annex C, section C.3 of ISO 19206-3:2021.
Therefore, the agency is adopting the new version of the ISO standard.
5. Articulation Properties
This final rule adopts the proposal that the legs of the pedestrian
test device be in accordance with, and as described in, Annex D,
section D.2 and illustrated in Figures D.1, D.2, and D.3 of ISO 19206-
2:2018. For the test scenarios involving a moving pedestrian, the legs
of the pedestrian test mannequin will articulate to simulate a walking
motion. A test mannequin that has leg articulation when in motion more
realistically represents an actual walking or running pedestrian. For
test scenarios involving a stationary pedestrian, the legs of the
pedestrian test mannequin remain at rest (i.e., simulate a standing
posture).
Commenters to this issue supported the pedestrian test mannequin
with articulation characteristics. The Alliance agreed that mannequins
equipped with articulate moving legs are more representative of actual
pedestrians than mannequins with stationary legs. While agreeing with
the NPRM, Aptiv noted that even when people are standing next to a
road, they move in some way (e.g., body micro-movement) and so NHTSA
may want to add some upper body movement to the stationary pedestrian
test mannequin. Porsche supported the adoption of articulated dummies,
explaining that the articulated motion is required because of the
``micro doppler'' effect, which is an important consideration for radar
sensors.
NHTSA has adopted the proposal for the articulation properties of
the legs. The agency is not adding pedestrian micro-movement to the
articulation requirements as there are currently no consensus standards
available for pedestrian micro-movement and NHTSA does not testing
experience with mannequins of that type.
6. Comments on Thermal Characteristics
In addition to the characteristics specified in the proposal
presented in the NPRM, NHTSA requested comments on whether test
mannequins should have thermal characteristics. Several commenters
\162\ responding to the NPRM discussed the merits of thermal
characteristics in the pedestrian test mannequins. Owl AI and Teledyne
explained that thermal imaging can capture infrared radiation emitted
by pedestrians in the 8-14[mu]m (long wave) band, which allows for
pedestrians to be easily distinguished from other objects. AAA
supported inclusion of thermal specifications, especially for nighttime
testing.
---------------------------------------------------------------------------

\162\ Commenters included Advocates, Adasky, Owl AI, Teledyne,
and AAA.
---------------------------------------------------------------------------

NHTSA currently does not have the body of research necessary to
develop test protocols that support the inclusion of thermally active
pedestrian test mannequins but concurs this matter may be a topic for
future consideration. NHTSA will continue to monitor the development of
thermally active pedestrian test mannequins so that the agency can
explore their use in the future.
N. Miscellaneous Topics
Advocates, ZF, AAA, Rivian, Volkswagen, AARP, the National
Associations of Mutual Insurance Companies, and ASC suggested a
requirement that vehicle manufacturers provide information in owners'
manuals and elsewhere describing how the AEB system works, and its
capabilities and its limitations. SEMA suggested a requirement that
specific information such as diagnostic codes and calibration
information be shared with consumers, MEMA suggested web links to
information, and NADA suggested using a QR code on the Monroney label.
SEMA also requested that NHTSA provide a system of information about
AEB to aftermarket suppliers.
In contrast, the Alliance and Hyundai opposed new information
requirements about AEB, suggesting that information is already provided
in the absence of a regulation. Additionally, the Alliance stated it is
unaware of the safety impacts of providing AEB information to
consumers.
This final rule has not adopted additional information
requirements. The agency concludes that the primary safety impacts from
AEB is the functionality itself. While information regarding the
capabilities and limitations of the AEB system may be generally useful,
AEB as required by this rule is a last second intervention system.
Thus, a driver's basic driving technique should not change based on the
capabilities or even the existence of AEB (aside from heeding the
warning of the malfunction indicator to attend to a problem with the
AEB system).
FCA believed that the proposed requirements overly focus
performance on the vehicle's braking system and not on the output of
the sensing and perception capacity of the AEB system. FCA further
stated that it could be possible to focus the regulatory requirement
solely onto the AEB system (i.e., the sensors and perception system) by
defining a perception mandate for output signals for time to warn or
the BRAKE! Command. FCA further asserted that this output could be
derived from fleet averages, equations of motion, and that as vehicle
performance improves, the timing could be revised accordingly.
In response, NHTSA declines FCA's suggestion to directly regulate
the sensing and perception systems directly instead of the ability of
the entire system to avoid crashes. This FMVSS is created with
important safety goals in mind to address significant safety problems
that this technology can resolve. For this rule, the safety problems
are rear-end crashes and crashes involving pedestrians struck by the
front of a vehicle. The performance requirements (avoiding contact with
a lead vehicle and pedestrian) address

[[Page 39764]]

this safety problem in an effective and expeditious manner. They are
solidly supported and informed by data from years of agency and
industry research, the voluntary commitment and NCAP, substantial
collaborative work between entities, and NHTSA's close monitoring of
AEB development and maturation. A new approach specifying a particular
time to collision based on the information from the perception system
is not supported by the current stated of knowledge and would take
years to research and develop.
FCA commented that NHTSA did not provide a baseline or compliance
assessment of the front lighting equipment installed in the research
vehicles, so manufacturers are unaware of the performance level of the
lighting relative to the FMVSS No. 108 range. For example, the vehicles
may have been equipped with optional lighting packages within the
product lineup, which may have enhanced performance. FCA also noted
that lighting was not included in the technical assessment or economic
analysis in the proposal. FCA expressed that NHTSA should have
knowledge regarding the high cost of modern lighting systems and
importantly, how much lead time would be needed to develop them, and
that performance requirements should not prohibit otherwise compliant
lighting systems. Finally, it stated that if improved lighting is
mandatory for AEB nighttime performance objectives, FMVSS No. 108
should be reconfigured in a separate rulemaking.
In response, NHTSA's performance-oriented approach in this final
rule directly addresses the safety problem while providing
manufacturers the most flexibility in designing vehicles to meet FMVSS
No. 127. Improved lighting is not a requisite of the final rule. A
manufacturer may choose to create a robust perception system that
initiates braking sooner, have a lesser performing perception system
and equip the vehicle with robust brakes, have a high performing
headlighting system to help achieve the performance required, or
implement another means of meeting the standard. Because FMVSS No. 127
is a performance standard, manufacturers decide what countermeasures
makes the most sense for them to meet the standard, and the marketplace
can continue to drive innovation while achieving positive safety
outcomes.

O. Effective Date and Phase-In Schedule

NHTSA proposed that all requirements be phased in within four years
of publication of a final rule. Under the proposal, all AEB-equipped
vehicles would be required to meet all requirements associated with
lead vehicle AEB within three years. NHTSA also proposed that all PAEB-
equipped vehicles would be required to meet all daylight test
requirements for PAEB within three years. For PAEB performance in
darkness, NHTSA proposed lower maximum test speed thresholds that would
have to be met within three years for some specified test procedures.
Under the proposal, all vehicles would be required to meet the minimum
performance requirements with higher darkness test speeds four years
after the publication of a final rule. Small-volume manufacturers,
final-stage manufacturers, and alterers would be provided an additional
year of lead time for all requirements.
NHTSA requested comments on the proposed lead time for meeting the
proposed requirements, and how the lead time can be structured to
maximize the benefits that can be realized most quickly while ensuring
that the standard is practicable.
Comments
In general, manufacturers, suppliers, and industry advocacy groups
asserted that more time is needed to meet the performance requirements
in the NPRM. In contrast, safety advocates and municipalities requested
that the proposed requirements be implemented sooner.
More specifically, the Alliance cited concerns over the
practicability of no contact, the NPRM's underestimation of the
software and hardware changes needed to facilitate crash avoidance at
higher speeds, and the complexity of addressing false positives all
within a short lead time. They expressed that it cannot be known
whether systems can achieve the proposed requirements through software
upgrades until a comprehensive system review, analysis, and synthesis
has been performed by manufacturers. Further, they expressed that the
proposed timeline could disrupt vehicle developments already underway
as it may require revisiting previous hardware and software design
decisions and redesigning systems expected to impact or be impacted by
the AEB/PAEB system. In addition, they stated that existing vehicle
electrical architectures may not be capable of handling the additional
or upgraded sensors, additional communication bandwidth and processing
power to upgrade the vehicle ADAS system to the proposed level of
performance.
The Alliance, Mitsubishi, Honda, and Nissan proposed a compliance
date starting seven years or more after the issuance of a final rule
for large volume manufacturers, and the Alliance suggested an
additional four years for small volume manufacturers. The Alliance
proposed an alternative compliance schedule that begins five years
after the issuance of a final rule but noted that this would not
address the outstanding technical issues and unintended consequences
that they outlined in their comments.
Volkswagen and Porsche suggested a phased-in compliance process
where a certain percentage of the fleet would be required to comply
over a period of several years until 100 percent of the fleet was
required to comply with the final rule. The Alliance and Nissan
suggested that if the agency considered its proposal to harmonize with
UNECE Regulation No. 152, compliance could occur sooner. Porsche and
Volkswagen suggested that compliance with UNECE Regulation No. 152
could be considered for end-of-production lines or as part of a phase-
in.
Bosch recommended a stepwise regulatory timeline, observing that
speeds up to 60 km/h are achievable as proposed in the NPRM, but
additional time would be necessary for testing at higher speeds.
Mobileye suggested a similar approach.
Advocates stated that the agency should require a more aggressive
schedule for compliance given the baseline inclusion of the components
for AEB systems in new vehicles. In addition, Advocates stated that
they oppose any further extension of the proposed compliance dates in
the NPRM. The NTSB encouraged NHTSA to consider reducing the timeline
for the rule's effective dates to expedite deployment as some
manufacturers may be able to achieve some of the performance
requirements immediately. Consumer Reports suggested that all
requirements, other than darkness pedestrian avoidance requirements, be
effective no later than one year after issuing a final rule. For
darkness pedestrian avoidance requirements, Consumer Reports stated
that NHTSA should set the compliance timeline at no more than two years
after publication of a final rule. NAMIC and IIHS stated that, based on
recent IIHS test data, manufacturers have made dramatic progress in
PAEB programs in a short time, and recommended a one-year phase-in.
Finally, NACTO, Richmond Ambulance Authority, DRIVE SMART Virginia, the
city of Philadelphia, the city of Houston, and the Nashville DOT
recommended that NHTSA have the higher speed pedestrian avoidance tests
in dark conditions required on the same timeline as the daytime
scenarios.

[[Page 39765]]

Agency Response
The agency finds the arguments for additional lead time compelling.
For the reasons discussed below, this final rule requires that
manufacturers comply with all provisions of this final rule at the end
of the five-year period starting the first September 1 after this
publication, or September 1, 2029. Most vehicles sold today do not meet
all of the requirements set forth in this final rule, and many may not
be easily made compliant with all of the requirements established in
this final rule. While NHTSA recognizes the urgency of the safety
problem, NHTSA also recognizes that the requirements of this final rule
are technology-forcing. The agency believes that the requirements are
crucial in ensuring the safety in the long run, but we are extending
the schedule to avoid significantly increasing the costs of this rule
by requiring that manufacturers conduct expensive equipment redesigns
outside of the normal product cycle. Because of the normal product
development cycle, it is likely that there will be significant market
penetration of complying systems as they are developed prior to the
effective date of this rule.
While some commenters suggested that the proposed lead time is
practicable if the agency reduced the stringency of this final rule's
requirements, such an approach would result in a substantial decrease
in the expected benefits of this rule in the long run. A lead time of
five years provides manufacturers with the ability to fully integrate
the AEB system into vehicles in line with the typical design cycle in
many cases. Such a process permits manufacturers to fully design
systems that minimize the false activations that industry has expressed
concern about, yet still provide the level of performance required by
this rule. NHTSA believes a five-year lead time fully balances safety
considerations, the capabilities of the technology, and the practical
need to engineer systems that fully comply with this final rule.
Note that as discussed in the Regulatory Flexibility Act section of
the document, NHTSA is giving certain small manufacturers and alterers
an additional year of lead time to comply with this rule.
Safety Act
Under 49 U.S.C. 30111(d), a standard may not become effective
before the 180th day after the standard is prescribed or later than one
year after it is prescribed, unless NHTSA finds, for good cause shown,
that a different effective date is in the public interest and publishes
a reason for the finding. A 5-year compliance period is in the public
interest because most vehicles will require upgrades of hardware or
software to meet the requirements of this final rule. To require
compliance with this standard outside of the normal development cycle
would significantly increase the cost of the rule because vehicles
cannot easily be made compliant with the requirements of this final
rule outside of the normal vehicle design cycle.

IV. Summary of Estimated Effectiveness, Cost, and Benefits

The requirements specified in this final rule for Lead Vehicle AEB
address rear-impact crashes. Between 2016 and 2019, an average of 1.12
million rear-impact crashes involving light vehicles occurred annually.
These crashes resulted in an annual average of 394 fatalities, 142,611
non-fatal injuries, and approximately 1.69 million property-damage-only
vehicles (PDOVs).
In specifying the requirements for Lead Vehicle AEB, the agency
considered the number of fatalities and non-fatal injuries resulting
from crashes that could potentially be prevented or mitigated given the
current capabilities of this technology. As a result, the requirements
specified for Lead Vehicle AEB consider the need to address this safety
issue by ensuring that these systems have sufficient braking authority
to generate speed reductions that can prevent or mitigate real-world
crashes.
The requirements specified in the final rule for PAEB address
crashes in which a light vehicle strikes a pedestrian. Between 2016 and
2019, an average of approximately 23,000 crashes that could potentially
be addressed by PAEB occurred annually. These crashes resulted in an
annual average of 2,642 fatalities and 17,689 non-fatal injuries.
In specifying the requirements for PAEB, the agency considered the
number of fatalities and non-fatal injuries resulting from crashes that
could potentially be prevented or mitigated given the current
capabilities of this technology. As a result, the requirements
specified for PAEB consider the need to address this safety issue by
ensuring that these systems have sufficient braking authority to
generate speed reductions that can prevent or mitigate real-world
crashes with pedestrians.
The target population for the lead vehicle AEB analysis includes
two-vehicle, rear-end light vehicle crashes and their resulting
occupant fatalities and non-fatal injuries. FARS is used to obtain the
target population for fatalities and CRSS is used to obtain the target
population for property-damage-only crashes and occupant injuries. The
target population includes two-vehicle light-vehicle to light-vehicle
crashes in which the manner of collision is a rear-end crash and the
first harmful event was a collision with a motor vehicle in transport.
Further refinement includes limiting the analysis to crashes where the
striking vehicle was traveling straight ahead prior to the collision at
a speed less than 90.1 mph (145 km/h) and the struck vehicle was either
stopped, moving, or decelerating.
[GRAPHIC] [TIFF OMITTED] TR09MY24.023

The target population for the PAEB analysis considered only light
vehicle crashes that included a single vehicle and pedestrian in which
the first injury-causing event was contact with a pedestrian. The area
of initial impact was limited to the front of the vehicle, specified as
clock points 11, 12, and 1, and the vehicle's pre-event movement was
traveling in a straight line.
These crashes were then categorized as either the pedestrian
crossing the vehicle path or along the vehicle path. The crashes are
inclusive of all light, road surface, and weather conditions to capture
potential crashes, fatalities, and injuries in real world conditions.
Data

[[Page 39766]]

elements listed as ``unknown'' were proportionally allocated, as
needed.
[GRAPHIC] [TIFF OMITTED] TR09MY24.024

A. Benefits

As a result of the requirements for Lead Vehicle AEB and PAEB
specified in this final rule, we estimate that 362 fatalities and more
than 24,000 non-fatal MAIS 1-5 injuries will be mitigated over the
course of one vehicle model year's lifetime.
[GRAPHIC] [TIFF OMITTED] TR09MY24.025

B. Costs

The agency estimated the incremental costs associated with this
final rule, which has been adjusted from the estimates presented in the
NPRM to include the costs associated with software and hardware
improvements, compared to the baseline condition. Incremental costs
reflect the difference in costs associated with all new light vehicles
being equipped with AEB with no performance standard (the baseline
condition) relative to all light vehicles being equipped with AEB that
meets the performance requirements specified in this final rule.
As common radar and camera systems are used across Lead Vehicle AEB
and PAEB systems, functionality can be achieved through upgraded
software for most of the affected vehicles. Therefore, the agency
accounts for the incremental cost associated with a software upgrade
for all new light vehicles. Although the majority of new light vehicles
would be able to achieve the minimum performance requirement without
adding additional hardware to their current AEB systems, a small
percentage would need to add either an additional camera or radar.
Based on the prevalence of mono-camera systems in our test data and in
NCAP reporting data, as well as a discussion with Bosch, this analysis
estimated that approximately five percent of new light vehicles would
require additional hardware.\163\ Therefore, in addition to software
costs, the agency also accounts for the incremental cost for five
percent of new light vehicles would add additional hardware (radar) to
their existing AEB systems in order to meet the requirements specified
in this final rule. Taking into account both software and hardware
costs, the total annual

[[Page 39767]]

cost associated with this final rule is approximately $354.06 million
in 2020 dollars.
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\163\ Ex Parte Docket Memo and Presentation_Bosch, available at:
https://www.regulations.gov/document/NHTSA-2023-0021-1058.
[GRAPHIC] [TIFF OMITTED] TR09MY24.026

C. Net Impact

The Benefits associated with this final rule, which are measured in
fatalities prevented and non-fatal injuries reduced, were converted
into equivalent lives saved. Under this final rule, the cost per
equivalent life saved ranges from $0.55 million and $0.68 million.
Therefore, the final rule is considered to be cost-effective. To
calculate net benefits, both measures must be represented in
commeasurable units. Therefore, total benefits are translated into
monetary value. When discounted at three and seven percent, the net
benefits associated with the final rule are $7.26 billion and $5.82
billion, respectively. Furthermore, when discounted at three and seven
percent, the benefit cost ratios associated with the final rule are
21.51 and 17.45, respectively. Therefore, this final rule is net
beneficial. Overall, the agency's analyses indicate that society will
be better off as a result of the final rule.
[GRAPHIC] [TIFF OMITTED] TR09MY24.027

[GRAPHIC] [TIFF OMITTED] TR09MY24.028

[GRAPHIC] [TIFF OMITTED] TR09MY24.029

[[Page 39768]]

V. Regulatory Notices and Analyses

Executive Orders 12866, 13563, and 14094 and DOT Regulatory Policies
and Procedures

The agency has considered the impact of this rulemaking action
under Executive Order (E.O.) 12866, E.O. 13563, E.O. 14094, and the
Department of Transportation's regulatory procedures. This rulemaking
is considered ``(3)(f)(1) significant'' and was reviewed by the Office
of Management and Budget under E.O. 12866, ``Regulatory Planning and
Review,'' as amended by E.O. 14094, ``Modernizing Regulatory Review.''
It is expected to have an annual effect on the economy of $200 million
or more. NHTSA has prepared a regulatory impact analysis that assesses
the cost and benefits of this rule, which has been included in the
docket listed at the beginning of this rule. The benefits, costs, and
other impacts of this rule are summarized in the final regulatory
impact analysis.

Regulatory Flexibility Act

The Regulatory Flexibility Act of 1980, as amended, requires
agencies to evaluate the potential effects of their proposed and final
rules on small businesses, small organizations, and small governmental
jurisdictions. The Small Business Administration's regulations at 13
CFR part 121 define a small business, in part, as a business entity
``which operates primarily within the United States.'' (13 CFR
121.105(a)). No regulatory flexibility analysis is required if the head
of an agency certifies that the rule will not have a significant
economic impact on a substantial number of small entities. The SBREFA
amended the Regulatory Flexibility Act to require Federal agencies to
provide a statement of the factual basis for certifying that a rule
will not have a significant economic impact on a substantial number of
small entities.
NHTSA has considered the effects of this final rule under the
Regulatory Flexibility Act.
The RIA discusses the economic impact of the rule on small vehicle
manufacturers, of which NHTSA is aware of 12. NHTSA believes that this
rule would not have a significant economic impact on these
manufacturers. The vehicles produced by manufacturers listed in RIA can
roughly be grouped into three classes: (1) luxury/ultra-luxury
vehicles; (2) alternative electric vehicles; and (3) modified vehicles
from other manufacturers. For luxury/ultra-luxury vehicles, any
potential incremental compliance costs would not impact demand.
Similarly, we would expect alternative electric vehicles to offer
amenities meeting or exceeding the established market alternatives,
including effective AEB and PAEB systems. Lastly, regarding final stage
manufacturers, NHTSA is aware that these manufacturers buy incomplete
vehicles from first-stage manufacturers. Then these vehicles are
modified from larger manufacturer stock that would already be
compliant. Therefore, there would be no incremental compliance costs.
As noted in the NPRM, much of the work developing and manufacturing
AEB system components would be conducted by suppliers. Although the
final certification would be made by the manufacturer, the NPRM
proposed allowing for one additional year for small-volume
manufacturers to comply with any requirement. That approach is similar
to the approach we have taken in other rulemakings in recognition of
manufacturing differences between larger and smaller manufacturers. As
the countermeasures are developed, AEB suppliers would likely supply
larger vehicle manufacturers first, before small manufacturers. In the
proposed rule, NHTSA recognized this and maintained the agency's
position that small manufacturers need additional flexibility, so they
have time to obtain the equipment and work with the suppliers after the
demands of the larger manufacturers are met.
The difference between the proposal and what is finalized in this
rule is that NHTSA is no longer pursuing different lead-times based on
the technology or phase-in schedules. Rather, the agency is providing
all manufacturers with two extra years of lead time for lead vehicle
AEB and one extra year of lead time for the most stringent requirements
for PAEB (i.e., 5 years of lead time regardless of technology). The
rule adopts a 5-year lead time for all requirements and all
manufacturers to ensure that the public attains lead vehicle AEB and
PAEB safety benefits as soon as practicable. Small volume manufacturers
would not have to comply for six years due to the additional year
provided to them.
This rule may also affect final stage manufacturers, many of whom
would be small businesses. While it is NHTSA's understanding that final
stage manufacturers rarely make modifications to a vehicle's braking
system and instead rely upon the pass-through certification provided by
a first-stage manufacturers, as with small-volume manufacturers, final
stage manufacturers would be provided with one additional year to
comply with any requirement.
NHTSA received comments on the Regulatory Flexibility Act analysis
included in the NPRM. One commenter asserted that NHTSA did not
adequately consider the additional burden for small volume
manufacturers and the unique design characteristics that would present
additional compliance challenges for small manufacturers. The unique
design considerations include low ground clearance, bumper
characteristics that would require mounting radar very close to the
ground, thereby requiring additional engineering to manage increased
sensor signal noise, the general shape of the bumper, and the materials
used for the bumper. This commenter said that the combination of these
factors raises the risk of false positives and/or angular distortion of
the target object in vertical and horizontal plane. Another commenter
raised concerns about the engineering challenges faced by manufacturers
of ``SuperCars'' and concern that these manufacturers would revert to
seeking exemptions instead of pursuing FMVSS compliance.
In response to these comments, NHTSA notes that it has extended the
lead time for all manufacturers to 5 years in this final rule. As
proposed, final stage manufacturers and small-volume manufacturers
would receive an additional year to comply, thus giving those entities
6 years to comply with this final rule. NHTSA believes that 6 years is
sufficient time for even the smallest manufacturers to design and
conform their products to this FMVSS, or seek an exemption if they have
grounds under one of the bases listed in 49 CFR part 555.
I certify that this final rule would not have a significant
economic impact on a substantial number of small entities. Additional
information concerning the potential impacts of this rule on small
entities is presented in the RIA accompanying this rule.

National Environmental Policy Act

The National Environmental Policy Act of 1969 (NEPA) \164\ requires
Federal agencies to analyze the environmental impacts of proposed major
Federal actions significantly affecting the quality of the human
environment, as well as the impacts of alternatives to the proposed
action.\165\ The Council on Environmental Quality (CEQ) directs Federal
agencies to prepare an environmental assessment for a proposed action
``that is not likely to

[[Page 39769]]

have significant effects or when the significance of the effects is
unknown.'' \166\ When a Federal agency prepares an environmental
assessment, CEQ's NEPA implementing regulations require it to (1)
``[b]riefly provide sufficient evidence and analysis for determining
whether to prepare an environmental impact statement or a finding of no
significant impact;'' and (2) ``[b]riefly discuss the purpose and need
for the proposed action, alternatives . . ., and the environmental
impacts of the proposed action and alternatives, and include a listing
of agencies and persons consulted.'' \167\
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\164\ 42 U.S.C. 4321-4347.
\165\ 42 U.S.C. 4332(2)(C).
\166\ 40 CFR 1501.5(a).
\167\ 40 CFR 1501.5(c).
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This section serves as NHTSA's Final Environmental Assessment (EA).
In this Final EA, NHTSA outlines the purpose and need for the
rulemaking, a reasonable range of alternative actions the agency
considered through rulemaking, the projected environmental impacts of
these alternatives. NHTSA did not receive any comments on the Draft EA.

Purpose and Need

This final rule sets forth the purpose of and need for this action.
In this final rule, NHTSA is adopting a new FMVSS to require AEB
systems on light vehicles capable of reducing the frequency and
severity of both lead vehicle rear-end (lead vehicle AEB) and
pedestrian crashes (PAEB). As explained earlier in this preamble, the
AEB system improves safety by using various sensor technologies and
sub-systems that work together to detect when the vehicle is in a crash
imminent situation, to automatically apply the vehicle brakes if the
driver has not done so, or to apply more braking force to supplement
the driver's braking, thereby detecting and reacting to an imminent
crash with a lead vehicle or pedestrian. This final rule promotes
NHTSA's goal to reduce the frequency and severity of crashes described
in the summary of the crash problem discussed earlier in the final
rule, and advances DOT's January 2022 National Roadway Safety Strategy
that identified requiring AEB, including PAEB technologies, on new
passenger vehicles as a key Departmental action to enable safer
vehicles. This final rule also responds to a mandate under the
Bipartisan Infrastructure Law (BIL) directing the Department to
promulgate such a rule.

Alternatives

NHTSA considered four regulatory alternatives for the proposed
action and a ``no action alternative.'' Under the no action
alternative, NHTSA would not issue a final rule requiring that vehicles
be equipped with systems that meet minimum specified performance
requirements, and manufacturers would continue to add AEB systems
voluntarily. However, because the BIL directs NHTSA to promulgate a
rule that would require that all passenger vehicles be equipped with an
AEB system, NHTSA cannot adopt the no action alternative. Alternative 1
considers requirements specific to lead vehicle AEB only. Alternative 2
includes the lead vehicle AEB requirements in Alternative 1 and a
requirement in which PAEB is only required to function in daylight
conditions. Alternative 3, the selected alternative, considers
requirements for lead vehicle AEBs and PAEB requirements in both
daylight and darkness conditions. Alternative 4 considers a more-
stringent requirement in which PAEB would be required to provide
pedestrian protections in turning scenarios (no change to the lead
vehicle AEB requirements in the final rule).
NHTSA also considered other options, including the International
Organization for Standardization (ISO) standards, SAE International
standards, the Economic Commission for Europe (ECE) standards, test
procedures used by NHTSA's New Car Assessment Program (NCAP) and Euro
NCAP, which are described above in this preamble and accompanying
appendices. In the final rule, NHTSA incorporates aspects of the test
procedures and standards mentioned here, but departs from them in
numerous and significant ways.

Environmental Impacts of the Proposed Action and Alternatives

This final rule is anticipated to result in the employment of
sensor technologies and sub-systems on light vehicles that work
together to sense when a vehicle is in a crash imminent situation, to
automatically apply the vehicle brakes if the driver has not done so,
and to apply more braking force to supplement the driver's braking if
insufficient. This final rule is also anticipated to improve safety by
mitigating the number of fatalities, non-fatal injuries, and property
damage that would result from crashes that could potentially be
prevented or mitigated because of AEB. As a result, the primary
environmental impacts \168\ that could potentially result from this
rulemaking are associated with: greenhouse gas emissions and air
quality, socioeconomics, public health and safety, solid waste/property
damage/congestion, and hazardous materials. Consistent with CEQ
regulations and guidance, this EA discusses impacts in proportion to
their potential significance. The effects of the final rule that were
analyzed further are summarized below.
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\168\ NHTSA anticipates that this rulemaking would have
negligible or no impact on the following resources and impact
categories, and therefore has not analyzed them further: topography,
geology, soils, water resources (including wetlands and
floodplains), biological resources, resources protected under the
Endangered Species Act, historical and archeological resources,
farmland resources, environmental justice, and section 4(f)
properties.
---------------------------------------------------------------------------

Greenhouse Gas Emissions and Air Quality

NHTSA has previously recognized that additional weight required by
FMVSS could potentially negatively impact the amount of fuel consumed
by a vehicle, and accordingly result in greenhouse gas emissions or air
quality impacts from criteria pollutant emissions. Atmospheric
greenhouse gases (GHGs) affect Earth's surface temperature by absorbing
solar radiation that would otherwise be reflected back into space.
Carbon dioxide (CO2) is the most significant greenhouse gas
resulting from human activity. Motor vehicles emit CO2 as
well as other GHGs, including methane and nitrous oxides, in addition
to criteria pollutant emissions that negatively affect public health
and welfare.
Additional weight added to a vehicle, like added hardware from
safety systems, can cause an increase in vehicle fuel consumption and
emissions. An AEB system requires the following hardware: sensing,
perception, warning hardware, and electronically modulated braking
subsystems.\169\ As discussed in the preamble and the RIA, NHTSA
anticipates that under the no action alternative and Alternatives 1-3,
the majority of vehicles subject to the rulemaking would already have
all of the hardware capable of meeting the requirements by the
effective date of a final rule. For all alternatives, NHTSA assumes
that manufacturers will need

[[Page 39770]]

time to build code that analyses the frontal view of the vehicle (i.e.,
manufacturers would need to upgrade the software for the perception
subsystem) in a way that achieves the requirements of this final rule.
Furthermore, approximately five percent of vehicles would add
additional hardware such as a camera or radar. In addition to those
costs, Alternative 4 includes an assumption that two cameras would be
added; however, based on weight assumptions included in studies cited
in the RIA, that weight impact would be minimal. The incremental weight
associated with a stereo camera module is 785 g (1.73 lbs.) and for the
entire camera and radar fused system is 883 g. (1.95 lbs.). NHTSA has
previously estimated that a 3-4-pound increase in vehicle weight is
projected to reduce fuel economy by 0.01 mpg.\170\ Accordingly,
Alternatives 1-3 would not have any fuel economy penalty for 95 percent
of vehicles subject to the rulemaking because no hardware would be
added. The potential impact on fuel economy for those five percent that
would add an additional hardware would be negligible as it would
potentially be under a pound when considering half the weight of either
the stereo camera module or camera and radar fused system or under two
pounds based on the stereo camera module. Similarly, Alternative 4
would potentially have a negligible fuel economy penalty as the
potential incremental weight would be under two pounds based on the
stereo camera module.
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\169\ Automatic actuation of a vehicle's brakes requires more
than just technology to sense when a collision is imminent. In
addition to the sensing system, hardware is needed to apply the
brakes without relying on the driver to depress the brake pedal. The
automatic braking system relies on two foundational braking
technologies--electronic stability control to automatically activate
the vehicle brakes and an antilock braking system to mitigate wheel
lockup. Not only do electronic stability control and antilock
braking systems enable AEB operation, these systems also modulate
the braking force so that the vehicle remains stable while braking
during critical driving situations where a crash with a vehicle or
pedestrian is imminent.
\170\ Final Regulatory Impact Analysis, Corporate Average Fuel
Economy for MYs 2012-2016 Passenger Cars and Light Trucks, Table IV-
5 (March 2010).
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Pursuant to the Clean Air Act (CAA), the U.S. Environmental
Protection Agency (EPA) has established a set of National Ambient Air
Quality Standards (NAAQS) for the following ``criteria'' pollutants:
carbon monoxide (CO), nitrogen dioxide (NO2), ozone,
particulate matter (PM) less than 10 micrometers in diameter
(PM10), PM less than 2.5 micrometers in diameter
(PM2.5), sulfur dioxide (SO2), and lead (Pb). The
NAAQS include ``primary'' standards and ``secondary'' standards.
Primary standards are intended to protect public health with an
adequate margin of safety. Secondary standards are set at levels
designed to protect public welfare by accounting for the effects of air
pollution on vegetation, soil, materials, visibility, and other aspects
of the general welfare. Under the General Conformity Rule of the
CAA,\171\ EPA requires a conformity determination when a Federal action
would result in total direct and indirect emissions of a criteria
pollutant or precursor originating in nonattainment or maintenance
areas equaling or exceeding the emissions thresholds specified in 40
CFR 93.153(b)(1) and (2). The General Conformity Rule does not,
however, require a conformity determination for Federal ``rulemaking
and policy development and issuance,'' such as this action.\172\
Therefore, NHTSA has determined it is not required to perform a
conformity analysis for this action.
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\171\ Section 176(c) of the CAA, codified at 42 U.S.C. 7506(c);
To implement CAA section 176(c), EPA issued the General Conformity
Rule (40 CFR part 51, subpart W and part 93, subpart B).
\172\ 40 CFR 93.153(c)(2)(iii).
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Socioeconomics

The socioeconomic impacts of the rulemaking would be primarily felt
by vehicle manufacturers, light vehicle drivers, passengers, and
pedestrians on the road that would otherwise be killed or injured in
light vehicle crashes. NHTSA conducted a detailed assessment of the
economic costs and benefits of establishing the new rule in its RIA.
The main economic benefits come primarily from the reduction in
fatalities and non-fatal injuries (safety benefits). Reductions in the
severity of motor vehicle crashes would be anticipated to have
corresponding reductions in costs for medical care, emergency services,
insurance administrative costs, workplace costs, and legal costs due to
the fatalities and injuries avoided. Other socioeconomic factors
discussed in the RIA that would affect these parties include software
and some hardware costs and property damage savings. Overall,
Alternative 1 is anticipated to have societal net benefits of $3.40 to
$4.28 billion, Alternative 2 is anticipated to have societal net
benefits of $4.23 to $5.30 billion, Alternative 3 (the selected
alternative) is anticipated to have societal net benefits of $5.82 to
$7.26 billion, and Alternative 4 is anticipated to have societal net
benefits of $4.18 to $5.73 billion. The RIA discusses this information
in further detail.

Public Health and Safety

The affected environment for public health and safety includes
roads, highways and other driving locations used by all light vehicle
drivers, other drivers, passengers in light vehicles and other motor
vehicles, and pedestrians or other individuals who could be injured or
killed in crashes involving the vehicles regulated by the proposed
action. In the RIA, the agency determined the impacts on public health
and safety by estimating the reduction in fatalities and injuries
resulting from the decreased crash severity due to the use of AEB
systems under the four action alternatives. Under Alternative 1, it is
expected that the addition of a less stringent requirement that only
specifies requirements for lead vehicle AEB would result each year in
314 to 388 equivalent lives saved. Under Alternative 2, it is expected
that the less-stringent requirement, in which PAEB is only required to
function in daylight conditions, would result each year in 384 to 473
equivalent lives saved. Under Alternative 3 (the selected alternative),
it is expected that the regulatory option would result each year in 517
to 638 equivalent lives saved. Finally, under Alternative 4, it is
expected that the addition of more stringent requirements in which PAEB
would be required to provide pedestrian protections in turning
scenarios would result each year in 555 to 684 equivalent lives saved.
The RIA discusses this information in further detail.

Solid Waste/Property Damage/Congestion

Vehicle crashes can generate solid wastes and release hazardous
materials into the environment. The chassis and engines, as well as
associated fluids and components of automobiles and the contents of the
vehicles, can all be deemed waste and/or hazardous materials. Solid
waste can also include damage to the roadway infrastructure, including
road surface, barriers, bridges, and signage. Hazardous materials are
substances that may pose a threat to public safety or the environment
because of their physical, chemical, or radioactive properties when
they are released into the environment, in this case as a result of a
crash.
NHTSA's rulemaking is projected to reduce the amount and severity
of light vehicle crashes, and therefore may reduce the quantity of
solid waste, hazardous materials, and other property damage generated
by light vehicle crashes in the United States. The addition of an AEB
system may also result in reduced damage to the vehicles and property,
as well as reduced travel delay costs due to congestion. This is
especially the case in ``property-damage-only'' crashes, where no
individuals are injured or killed in the crash, but there may be damage
to the vehicle or whatever is impacted by it. NHTSA estimates that
based off data from 2016-2019 alone, an average of 1.12 million rear-
impact crashes involving light vehicles occurred

[[Page 39771]]

annually. These crashes resulted in an annual average of 394
fatalities, 142,611 non-fatal injuries, and approximately 1.69 million
PDOVs.
Less solid waste translates into cost and environmental savings
from reductions in the following areas: (1) transport of waste
material, (2) energy required for recycling efforts, and (3) landfill
or incinerator fees. Less waste will result in beneficial environmental
effects through less GHG emissions used in the transport of it to a
landfill, less energy used to recycle the waste, less emissions through
the incineration of waste, and less point source pollution at the scene
of the crash that would result in increased emissions levels or
increased toxins leaking from the crashed vehicles into the surrounding
environment.
The addition of an AEB system may also result in reduced post-crash
environmental effects from congestion. As discussed in the RIA, NHTSA's
monetized benefits are calculated by multiplying the number of non-
fatal injuries and fatalities mitigated by their corresponding
``comprehensive costs.'' The comprehensive costs include economic costs
that are external to the value of a statistical life (VSL) costs, such
as emergency management services or legal costs, and congestion costs.
NHTSA has recognized that motor vehicle crashes result in congestion
that has both socioeconomic and environmental effects. These
environmental effects include ``wasted fuel, increased greenhouse gas
production, and increased pollution as engines idle while drivers are
caught in traffic jams and slowdowns.'' \173\ NHTSA's monetized
benefits therefore include a quantified measure of congestion
avoidance. NHTSA did not calculate congestion effects specifically for
each regulatory alternative; however, because comprehensive costs are a
discrete cost applied to non-fatal injuries and fatalities at the same
rate, we can conclude that there are increasing benefits associated
with fewer crashes, and specifically decreased congestion, as the
monetized benefits increase across regulatory alternatives. To the
extent that any regulatory option for AEB results in fewer crashes and
accordingly higher monetized benefits, there would be fewer congestion-
related environmental effects.
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\173\ Blincoe, L.J., Miller, T.R., Zaloshnja, E., & Lawrence,
B.A. (2015, May). The economic and societal impact of motor vehicle
crashes, 2010. (Revised) (Report No. DOT HS 812 013). Washington,
DC: National Highway Traffic Safety Administration.
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NHTSA has tentatively concluded that under the agency's rulemaking,
the economic benefits resulting from improved safety outcomes, property
damage savings, fuel savings, and GHG reductions would limit the
negative environmental impacts caused by additional solid waste/
property damage due to crashes because of the crashes that will be
avoided due to the requirements of this rule. Similarly, while the
potential degree of hazardous materials spills prevented due to the
reduction of crash severity and crash avoidance expected from the
rulemaking has not specifically been analyzed in the RIA or final rule,
the addition of the AEB system is projected to reduce the amount and
severity of light vehicle crashes and may improve the environmental
effects with respect to hazardous material spills. While the RIA does
not specifically quantify these impact categories, in general NHTSA
believes the benefits would increase relative to the crashes avoided
and would be relative across the different alternatives. The RIA
discusses information related to quantified costs and benefits of
crashes, and in particular property damage due to crashes, for each
regulatory alternative in further detail.

Cumulative Impacts

In addition to direct and indirect effects, CEQ regulations require
agencies to consider cumulative impacts of major Federal actions. CEQ
regulations define cumulative impacts as the impact ``on the
environment that result from the incremental [impact] of the action
when added to . . . other past, present, and reasonably foreseeable
actions regardless of what agency (Federal or non-Federal) or person
undertakes such other actions.'' \174\ NHTSA notes that the public
health and safety, solid waste/property damage/congestion, air quality
and greenhouse gas emissions, socioeconomic, and hazardous material
benefits identified in this EA were based on calculations described in
the RIA, in addition to other NHTSA actions and studies on motor
vehicle safety as described in the preamble. That methodology required
the agency to adjust historical figures to reflect vehicle safety
rulemakings that have recently become effective. As a result, many of
the calculations in this EA already reflect the incremental impact of
this action when added to other past actions.
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\174\ 40 CFR 1508.1(g)(3).
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NHTSA's and other parties' past actions that improve the safety of
light vehicles, as well as future actions taken by the agency or other
parties that improve the safety of light vehicles, could further reduce
the severity or number of crashes involving light vehicles. Any such
cumulative improvement in the safety of light vehicles would have an
additional effect in reducing injuries and fatalities and could reduce
the quantity of solid and hazardous materials generated by crashes. To
the extent that this rule may have some minimal impact on fuel economy
for the small percentage of vehicles where additional hardware may be
required, NHTSA would consider that impact when setting maximum
feasible fuel economy standards.'' \175\
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\175\ 49 U.S.C. 32902(f), which states that we consider the
effect of other motor vehicle standards of the Government on fuel
economy in the max feasible discussion.
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Agencies and Persons Consulted

This preamble describes the various materials, persons, and
agencies consulted in the development of the final rule. NHTSA invited
public comments on the contents and tentative conclusions of the Draft
EA. No public comments addressing the Draft EA were received.
Furthermore, none of the public comments that were received addressed
any issues related to the human environment that would be relevant to
the Final EA.

Finding of No Significant Impact

Although this rule is anticipated to result in additional FMVSS
requirements for light vehicle manufacturers, AEB systems have already
largely been introduced by manufacturers voluntarily. The addition of
regulatory requirements (depending on the regulatory alternative) to
standardize the AEB systems in all vehicle models is anticipated to
result in negligible or no fuel economy and emissions penalties (i.e.,
five percent of vehicles would require additional hardware, but the
added weight is negligible), increasing socioeconomic and public safety
benefits as the alternatives get more stringent, and an increase in
benefits from the reduction in solid waste, property damage, and
congestion (including associated traffic level impacts like reduction
in energy consumption and tailpipe pollutant emissions) from fewer
vehicle crashes across the regulatory alternatives.
Based on the Final EA, NHTSA concludes that implementation of any
of the alternatives considered for the proposed action, including the
selected alternative, will not have a significant effect on the human
environment and that a ``finding of no significant impact''

[[Page 39772]]

is appropriate. This statement constitutes the agency's ``finding of no
significant impact,'' and an environmental impact statement will not be
prepared.\176\
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\176\ 40 CFR 1501.6(a).
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Executive Order 13132 (Federalism)

NHTSA has examined this rule pursuant to Executive Order 13132 (64
FR 43255, August 10, 1999) and concluded that no additional
consultation with States, local governments, or their representatives
is mandated beyond the rulemaking process. The agency has concluded
that this rule will not have sufficient federalism implications to
warrant consultation with State and local officials or the preparation
of a federalism summary impact statement. The rule does not have
``substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.''
NHTSA rules can preempt in two ways. First, the National Traffic
and Motor Vehicle Safety Act contains an express preemption provision:
When a motor vehicle safety standard is in effect under this chapter, a
State or a political subdivision of a State may prescribe or continue
in effect a standard applicable to the same aspect of performance of a
motor vehicle or motor vehicle equipment only if the standard is
identical to the standard prescribed under this chapter. 49 U.S.C.
30103(b)(1). It is this statutory command by Congress that preempts any
non-identical State legislative and administrative law addressing the
same aspect of performance. The express preemption provision described
above is subject to a savings clause under which compliance with a
motor vehicle safety standard prescribed under this chapter does not
exempt a person from liability at common law. 49 U.S.C. 30103(e).
Pursuant to this provision, State common law tort causes of action
against motor vehicle manufacturers that might otherwise be preempted
by the express preemption provision are generally preserved. However,
the Supreme Court has recognized the possibility, in some instances, of
implied preemption of such State common law tort causes of action by
virtue of NHTSA's rules, even if not expressly preempted. The second
way that NHTSA rules can preempt is dependent upon there being an
actual conflict between an FMVSS and the higher standard that would
effectively be imposed on motor vehicle manufacturers if someone
obtained a State common law tort judgment against the manufacturer,
notwithstanding the manufacturer's compliance with the NHTSA standard.
Because most NHTSA standards established by an FMVSS are minimum
standards, a State common law tort cause of action that seeks to impose
a higher standard on motor vehicle manufacturers will generally not be
preempted. If and when such a conflict does exist--for example, when
the standard at issue is both a minimum and a maximum standard--the
State common law tort cause of action is impliedly preempted. See Geier
v. American Honda Motor Co., 529 U.S. 861 (2000).
Pursuant to Executive Orders 13132 and 12988, NHTSA has considered
whether this rule could or should preempt State common law causes of
action. The agency's ability to announce its conclusion regarding the
preemptive effect of one of its rules reduces the likelihood that
preemption will be an issue in any subsequent tort litigation. To this
end, the agency has examined the nature (i.e., the language and
structure of the regulatory text) and objectives of this rule and finds
that this rule, like many NHTSA rules, would prescribe only a minimum
safety standard. As such, NHTSA does not intend this rule to preempt
state tort law that would effectively impose a higher standard on motor
vehicle manufacturers. Establishment of a higher standard by means of
State tort law will not conflict with the minimum standard adopted
here. Without any conflict, there could not be any implied preemption
of a State common law tort cause of action.

Executive Order 12988 (Civil Justice Reform)

When promulgating a regulation, section 3(b) of Executive Order
12988, ``Civil Justice Reform'' (61 FR 4729, February 7, 1996) requires
that Executive agencies make every reasonable effort to ensure that the
regulation: (1) Clearly specifies the preemptive effect; (2) clearly
specifies the effect on existing Federal law or regulation; (3)
provides a clear legal standard for affected conduct, while promoting
simplification and burden reduction; (4) clearly specifies the
retroactive effect, if any; (5) adequately defines key terms; and (6)
addresses other important issues affecting clarity and general
draftsmanship under any guidelines issued by the Attorney General. This
document is consistent with that requirement.
Pursuant to this Order, NHTSA notes that the preemptive effect of
this rulemaking is discussed above in connection with Executive Order
13132. NHTSA notes further that there is no requirement that
individuals submit a petition for reconsideration or pursue other
administrative proceeding before they may file suit in court.

Executive Order 13045 (Protection of Children From Environmental Health
and Safety Risks)

Executive Order 13045, ``Protection of Children from Environmental
Health and Safety Risks,'' (62 FR 19885; April 23, 1997) applies to any
proposed or final rule that: (1) Is determined to be ``economically
significant,'' as defined in E.O. 12866, and (2) concerns an
environmental health or safety risk that NHTSA has reason to believe
may have a disproportionate effect on children. If a rule meets both
criteria, the agency must evaluate the environmental health or safety
effects of the rule on children, and explain why the rule is preferable
to other potentially effective and reasonably feasible alternatives
considered by the agency.
This rule is not expected to have a disproportionate health or
safety impact on children. Consequently, no further analysis is
required under Executive Order 13045.

Congressional Review Act

The Congressional Review Act, 5 U.S.C. 801 et. seq., as added by
the Small Business Regulatory Enforcement Fairness Act of 1996,
generally provides that before a rule may take effect, the agency
promulgating the rule must submit a rule report, which includes a copy
of the rule, to each House of the Congress and to the Comptroller
General of the United States. NHTSA will submit a report containing
this rule and other required information to the U.S. Senate, the U.S.
House of Representatives, and the Comptroller General of the United
States prior to publication of the rule in the Federal Register.
Because this rule meets the criteria in 5 U.S.C. 804(2), it will be
effective sixty days after the date of publication in the Federal
Register.

Paperwork Reduction Act (PRA)

Under the PRA of 1995, a person is not required to respond to a
collection of information by a Federal agency unless the collection
displays a valid OMB control number. There are no ``collections of
information'' (as defined at 5 CFR 1320.3(c)) in this rule.

[[Page 39773]]

National Technology Transfer and Advancement Act

Under the National Technology Transfer and Advancement Act of 1995
(NTTAA) (Pub. L. 104-113), all Federal agencies and departments shall
use technical standards developed or adopted by voluntary consensus
standards bodies, using such technical standards as a means to carry
out policy objectives or activities determined by the agencies and
departments. Voluntary consensus standards are technical standards
(e.g., materials specifications, test methods, sampling procedures, and
business practices) developed or adopted by voluntary consensus
standards bodies, such as the International Organization for
Standardization and SAE International. The NTTAA directs us to provide
Congress, through OMB, explanations when we decide not to use available
and applicable voluntary consensus standards.
NHTSA is incorporating by reference ISO and ASTM standards into
this rule. NHTSA considered several ISO standards and has opted to use
ISO 19206-3:2021 to specify the vehicle test device and a combination
of ISO 19206-2:2018 and ISO 19206-4:2020 to specify the test
mannequins. NHTSA is incorporating by reference ASTM E1337-19, which is
already incorporated by reference into many FMVSSs, to measure the peak
braking coefficient of the testing surface.
NHTSA considered SAE International Recommended Practice J3087,
``Automatic emergency braking (AEB) system performance testing,'' which
defines the conditions for testing AEB and FCW systems. This standard
defines test conditions, test targets, test scenarios, and measurement
methods, but does not provide performance criteria. There is
considerable overlap in the test setup and conditions between this rule
and the SAE standard including the basic scenarios of lead vehicle
stopped, slower moving, and decelerating. This SAE recommended practice
is substantially similar to the existing NCAP test procedures and this
rule.
NHTSA also considered SAE International Standard J3116, ``Active
Safety Pedestrian Test Mannequin Recommendation,'' which provides
recommendations for the characteristics of a surrogate that could be
used in testing of active pedestrian safety systems. As proposed, NHTSA
incorporates the ISO standard because the ISO standard specifications
are more widely adopted than the SAE Recommended Practice.
In appendix B of the NPRM's preamble, NHTSA described several
international test procedures and regulations the agency considered for
use in this rule. This rule has substantial technical overlap with
UNECE Regulation No. 131 and UNECE Regulation No. 152. This rule and
the UNECE regulations both specify a forward collision warning and
automatic emergency braking. Several lead vehicle AEB scenarios are
nearly identical, including the lead vehicle stopped and lead vehicle
moving scenarios. The pedestrian crossing path scenario specified in
UNECE Regulation No. 152 is also substantially similar to this rule. As
discussed in the preamble, this rule differs from the UNECE standards
in the areas of maximum test speed and the minimum level of required
performance. This rule uses higher test speeds and a requirement that
the test vehicle avoid contact, both of which are more stringent than
the UNECE regulations and more reflective of the safety need in the
United States. NHTSA expects that this approach would increase the
repeatability of the test and maximize the realized safety benefits of
the rule.

Incorporation by Reference

Under regulations issued by the Office of the Federal Register (1
CFR 51.5), an agency, as part of a proposed rule that includes material
incorporated by reference, must summarize material that is proposed to
be incorporated by reference and discuss the ways the material is
reasonably available to interested parties or how the agency worked to
make materials available to interested parties. At the final rule
stage, regulations require that the agency seek formal approval,
summarize the material that it incorporates by reference in the
preamble of the final rule, discuss the ways that the materials are
reasonably available to interested parties, and provide other specific
information to the Office of the Federal Register.
In this rule, NHTSA incorporates by reference six documents into
the Code of Federal Regulations, ASTM E1337-19, Standard Test Method
for Determining Longitudinal Peak Braking Coefficient (PBC) of Paved
Surfaces Using Standard Reference Test Tire, is already incorporated by
reference elsewhere in 49 CFR part 571. ASTM E1337 is a standard test
method for evaluating peak braking coefficient of a test surface using
a standard reference test tire using a trailer towed by a vehicle.
NHTSA uses this method in all of its braking and electronic stability
control standards to evaluate the test surfaces for conducting
compliance test procedures.
NHTSA also incorporates by reference SAE J2400 Human Factors in
Forward Collision Warning System: Operating Characteristics and User
Interface Requirements, into part 571. SAE J2400 is an information
report intended as a starting point of reference for designers of
forward collision warning systems. NHTSA incorporates this document by
reference solely to specify the location specification and symbol for a
visual forward collision warning.
NHTSA incorporates by reference four ISO standards into 49 CFR part
596. The first of these standards is ISO 3668:2017(E), Paints and
varnishes--Visual comparison of colour of paints. This document
specifies a method for the visual comparison of the color of paints
against a standard. This method will be used to verify the color of
certain elements of the pedestrian test mannequin NHTSA will use in
PAEB testing. Specifically, NHTSA will use these procedures to
determine that the color of the hair, torso, arms, and feet of the
pedestrian test mannequin is black and that the color of the legs are
blue.
NHTSA incorporates by reference ISO 19206-2:2018(E), Road
vehicles--Test devices for target vehicles, vulnerable road users and
other objects, for assessment of active safety functions--Part 2:
Requirements for pedestrian targets. This document addresses the
specification for a test mannequin. It is designed to resemble the
characteristics of a human, while ensuring the safety of the test
operators and preventing damage to subject vehicles in the event of a
collision during testing. NHTSA references many, but not all, of the
specifications of ISO 19206-2:2018, as discussed earlier in the
preamble of this rule.
NHTSA also incorporates by reference ISO 19206-3:2021(E), Test
devices for target vehicles, vulnerable road users and other objects,
for assessment of active safety functions--Part 3: Requirements for
passenger vehicle 3D targets. This document provides specification of
three-dimensional test devices that resemble real vehicles. Like the
test mannequin described in the prior paragraph, it is designed to
ensure the safety of the test operators and to prevent damage to
subject vehicles in the event of a collision during testing. NHTSA
references many, but not all, of the specifications of ISO 19206-
3:2021, as discussed earlier in the preamble of this rule.
Finally, NHTSA incorporates by reference ISO 19206-4:2020(E), Road
vehicles--test devices for target vehicles,

[[Page 39774]]

vulnerable road users and other objects, for assessment of active
safety functions--Part 4: Requirements for bicyclists targets. This
standard describes specifications for bicycle test devices
representative of adult and child sizes. NHTSA will not use a bicycle
test device during testing for this final rule. Rather, this standard
is incorporated by reference solely because it contains specifications
for color and reflectivity, including skin color, that NHTSA is
applying to its pedestrian test mannequin.
All standards incorporated by reference in this rule are available
for review at NHTSA's headquarters in Washington, DC, and for purchase
from the organizations promulgating the standards (see 49 CFR 517.5 for
contact information). The ASTM standard presently incorporated by
reference into other NHTSA regulations is also available for review at
ASTM's online reading room.\177\
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\177\ https://www.astm.org/products-services/reading-room.html.
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Unfunded Mandates Reform Act

The Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires
agencies to prepare a written assessment of the costs, benefits, and
other effects of proposed or final rules that include a Federal mandate
likely to result in the expenditures by States, local or tribal
governments, in the aggregate, or by the private sector, of more than
$100 million annually (adjusted annually for inflation with base year
of 1995). Adjusting this amount by the implicit gross domestic product
price deflator for 2021 results in an estimated current value of $165
million (2021 index value of 113.07/1995 index value of 68.60 = 1.65).
The assessment may be included in conjunction with other assessments,
as it is for this rule in the RIA.
A rule on lead vehicle AEB and PAEB is not likely to result in
expenditures by State, local or tribal governments of more than $100
million annually. However, it is estimated to result in the estimated
expenditure by automobile manufacturers and/or their suppliers of $354
million annually (estimated to be an average of approximately $23 per
light vehicle annually). This average estimated cost impacts reflects
that the estimated incremental costs depend on a variety of lead
vehicle AEB hardware and software that manufacturers plan to install
(in vehicles used as ``baseline'' for the cost estimate). The final
cost will greatly depend on choices made by the automobile
manufacturers to meet the lead vehicle AEB and PAEB test requirements.
These effects have been discussed in the RIA developed in support of
this final rule.
The Unfunded Mandates Reform Act requires the agency to select the
``least costly, most cost-effective or least burdensome alternative
that achieves the objectives of the rule.'' As an alternative, the
agency considered a full-vehicle dynamic test to evaluate the
capability of lead vehicle AEB and PAEB systems to prevent crashes or
mitigate the severity of crashes. Based on our experience on conducting
vehicle tests for vehicles equipped with lead vehicle AEB and PAEB
where we utilize a reusable surrogate target crash vehicle and test
mannequins instead of conducting the test with an actual vehicle as the
target, we determined that full vehicle-to-vehicle crash tests can have
an undesired amount of variability in vehicle kinematics. Unlike
vehicle-to-vehicle tests, the lead vehicle AEB and PAEB tests with a
surrogate target vehicle is conducted in a well-controlled test
environment, which results in an acceptable amount of variability. In
addition, the agency's lead vehicle AEB and PAEB tests with surrogate
target vehicle and pedestrian were able to reveal deficiencies in the
system that resulted in inadequate system capability in detecting and
activating the brakes. Therefore, we concluded that a full vehicle-to-
vehicle test would not achieve the objectives of the rule.
In addition, the agency evaluated data across a broad range of test
scenarios in an effort to identify the maximum range of test speeds at
which it is feasible for test vehicles to achieve a no-contact result.
The range of feasible speeds for no contact identified in the review
was specified as the mandated range in the rule. Thus, there are no
alternative test procedures available that would improve the ability of
manufacturers to achieve no-contact results. In turn, the agency
concluded that lead vehicle AEB and PAEB systems designed to meet the
no-contact requirement at speeds outside the ranges specified in the
rule would not achieve the objectives of the rule.

Executive Order 13609 (Promoting International Regulatory Cooperation)

The policy statement in section 1 of E.O. 13609 states, in part,
that the regulatory approaches taken by foreign governments may differ
from those taken by U.S. regulatory agencies to address similar issues
and that, in some cases, the differences between the regulatory
approaches of U.S. agencies and those of their foreign counterparts
might not be necessary and might impair the ability of American
businesses to export and compete internationally. The E.O. states that,
in meeting shared challenges involving health, safety, labor, security,
environmental, and other issues, international regulatory cooperation
can identify approaches that are at least as protective as those that
are or would be adopted in the absence of such cooperation, and that
international regulatory cooperation can also reduce, eliminate, or
prevent unnecessary differences in regulatory requirements. NHTSA
requested public comment on the ``regulatory approaches taken by
foreign governments'' concerning the subject matter of this rulemaking.
NHTSA received many comments expressing that NHTSA should either align
or adopt existing international regulations. As discussed above, while
NHTSA has adopted aspects of these regulations, it has rejected others
because of the stringency of the regulations due to the reasons
discussed in further detail in various parts of the preamble and
National Technology Transfer and Advancement Act section.

Severability

The issue of severability of FMVSSs is addressed in 49 CFR 571.9.
It provides that if any FMVSS or its application to any person or
circumstance is held invalid, the remainder of the part and the
application of that standard to other persons or circumstances is
unaffected. It expresses NHTSA's view that, even with invalidated
portions or applications disregarded, remaining portions and
applications can still function sensibly.

Regulation Identifier Number

The Department of Transportation assigns a regulation identifier
number (RIN) to each regulatory action listed in the Unified Agenda of
Federal Regulations. The Regulatory Information Service Center
publishes the Unified Agenda in April and October of each year. You may
use the RIN contained in the heading at the beginning of this document
to find this action in the Unified Agenda.

VI. Appendices to the Preamble

A. Appendix A: Description of the Lead Vehicle AEB Test Procedures
Stopped Lead Vehicle

Test Parameters
The stopped lead vehicle scenario consists of the vehicle traveling
straight ahead, at a constant speed, approaching a stopped lead vehicle
in its path. The vehicle must be able to avoid contact with the stopped
lead vehicle. The testing is at any subject vehicle speed

[[Page 39775]]

between 10 km/h and 80 km/h with no manual brake application and
between 70 km/h and 100 km/h with manual brake application.
Test Conduct Prior to FCW Onset
Prior to the start of a test, the lead vehicle is placed with its
longitudinal centerline coincident to the intended travel path and with
no specific limitations on how a subject vehicle may be driven prior to
the test start. As long as the specified initialization procedure is
executed, a subject vehicle may be driven under any conditions
including any speed and direction, and on any road surface, for any
elapsed time prior to reaching the point where a test trial begins. As
the subject vehicle approaches the rear of the lead vehicle, beginning
when the headway corresponds to L0, the subject vehicle
speed is maintained within 1.6 km/h of the test speed with minimal and
smooth accelerator pedal inputs. Furthermore, beginning when the
headway corresponds to L0, the subject vehicle heading is
maintained with minimal steering input such that the subject vehicle
travel path does not deviate more than 0.3 m laterally from the
intended travel path and the subject vehicle's yaw rate does not exceed
1.0 deg/s. The purpose of these test tolerances is to
assure test practicability and repeatability of results.
Test Conduct After FCW Onset
During each test, the subject vehicle accelerator pedal is released
in response to the FCW. The procedure states that the accelerator pedal
is released at any rate and is fully released within 500 milliseconds
for subject vehicles tested without cruise control active. The
accelerator release procedure ensures consistent release of the
accelerator and assures test repeatability. The accelerator pedal
release can be omitted from tests of vehicles with cruise control
actively engaged because there is no driver input to the accelerator
pedal in that case. The AEB performance requirements are the same for
vehicles with and without cruise control engaged, and AEB systems must
provide an equivalent level of crash avoidance or mitigation regardless
of whether cruise control is active.
For testing without manual brake application, no manual brake
application is made until one of the test completion criteria is
satisfied. For tests that include manual brake application, the service
brakes are applied at 1.0 0.1 second after FCW.
Test Completion Criteria
Any test is complete when the subject vehicle comes to a complete
stop without making contact with the lead vehicle or when the subject
vehicle makes contact with the lead vehicle.
Slower-Moving Lead Vehicle
Test Parameters
The slower-moving lead vehicle scenario involves the subject
vehicle traveling straight ahead at constant speed, approaching a lead
vehicle traveling at a slower speed in the subject vehicle path. NHTSA
will test at the same two subject vehicle speed ranges as the stopped
lead vehicle scenario depending on the manual brake application. The
lead vehicle speed is 20 km/h.
Test Conduct Prior to FCW Onset
Prior to the start of a test trial the lead vehicle is propelled
forward in a manner such that the longitudinal center plane of the lead
vehicle does not deviate laterally more than 0.3m from the intended
travel path.
As the subject vehicle approaches the rear of the lead vehicle,
beginning when the headway corresponds to L0, the subject
vehicle speed is maintained within 1.6 km/h of the test speed with
minimal and smooth accelerator pedal inputs. Furthermore, beginning
when the headway corresponds to L0, the subject vehicle and
lead heading are to be maintained with minimal steering input such that
the subject vehicle travel path does not deviate more than 0.3 m
laterally from the intended travel path and the subject vehicle's yaw
rate does not exceed 1.0 deg/s.
Test Conduct After FCW Onset
Similar to the stopped lead vehicle test, the subject vehicle
accelerator pedal is released in response to the FCW. The procedure
states that the accelerator pedal is released at any rate and is fully
released within 500 milliseconds for subject vehicles tested without
cruise control active. The accelerator pedal release can be omitted
from tests of vehicles with cruise control actively engaged due to the
lack of driver input to the accelerator pedal.
For testing without manual brake application, no manual brake
application is made until one of the test completion criteria is
satisfied. For testing with manual brake application, the service brake
application occurs at 1.0 0.1 second after FCW onset.
Test Completion Criteria
Any test run is complete when the subject vehicle speed is less
than or equal to the lead vehicle speed without making contact with the
lead vehicle or when the subject vehicle makes contact with the lead
vehicle.
Decelerating Lead Vehicle
Test Parameters
The decelerating lead vehicle scenario is meant to assess the AEB
performance when the subject vehicle and lead vehicle initially are
travelling at the same constant speed in a straight path and the lead
vehicle begins to decelerate. NHTSA tests under two basic setups for
this scenario, one where both the subject vehicle and lead vehicle
initial travel speed (VSV = VLV) is 50 km/h and
another where both vehicles travel at 80 km/h. For both testing speeds,
NHTSA tests with, and without, manual brake application, at any headway
between 12 m and 40 m and at any lead vehicle deceleration between 0.3
g and 0.5 g.
Test Conduct Prior to Lead Vehicle Braking Onset
Up to 3 seconds prior to the start of a test trial there are no
specific limitations on how a subject vehicle may be driven. Between 3
seconds prior and the lead vehicle braking onset, the lead vehicle is
propelled forward in a manner such that the longitudinal center plane
of the lead vehicle does not deviate laterally more than 0.3m from the
intended travel path. During this same time interval, the subject
vehicle follows the lead vehicle at the testing headway distance
between 12 m and 40m. While the subject vehicle follows the lead
vehicle from 3 seconds prior and lead vehicle brake onset, the subject
vehicle and lead vehicle speeds are maintained within 1.6 km/h and
their travel paths do not deviate more than 0.3 m laterally from the
centerline of the lead vehicle. The speed is to be maintained with
minimal and smooth accelerator pedal inputs and the and yaw rate of the
subject vehicle may not exceed 1.0 deg/s.
Test Conduct After Lead Vehicle Braking Onset
The lead vehicle is decelerated to a stop with a targeted average
deceleration of any value between 0.3g and 0.5g. The targeted
deceleration magnitude is to be achieved within 1.5 seconds of lead
vehicle braking onset and maintained until 250 ms prior to coming to a
stop. Similar to the lead vehicle tests, during each test trial, the
subject vehicle accelerator pedal is released in response to the FCW
and fully released within 500 milliseconds.
In the same manner as the slower lead vehicle tests, when testing
without

[[Page 39776]]

manual brake application, no manual brake application is made until one
of the test completion criteria is satisfied. For testing with manual
brake application, the service brake application occurs at 1.0 0.1 second after FCW onset.
Test Completion Criteria
Any test run is complete when the subject vehicle comes to a
complete stop without making contact with the lead vehicle or when the
subject vehicle makes contact with the lead vehicle, similarly to the
stopped lead vehicle tests.
Headway Calculation
For the scenarios where the headway is not specified (stopped lead
vehicle and slower lead vehicle) the headway (L0), in meters, providing
5 seconds time to collision (TTC) is calculated. L0 is determined with
the following equation where VSV is the speed of the subject vehicle in
m/s and VLV is the speed of the lead vehicle in m/s:

L0 = TTC0 x (VSV-VLV)
TTC0 = 5.0
Travel Path
The intended travel path is the target path for a given test
scenario and is identified by the projection onto the road surface of
the frontmost point of the subject vehicle located on its longitudinal,
vertical center plane. The subject vehicle's actual travel path is
recorded and compared to the intended path.
The intended subject vehicle travel path is coincident with the
center of a test lane whenever there are two edge lines marking a lane
on the test track surface. If there is only one lane line (either a
single or double line) marked on the test track, the vehicle path will
be parallel to it and offset by 1.8 m (6 ft) to one side (measured from
the inside edge of the line).
Subject Vehicle (Manual) Brake Application Procedures
Subject vehicle brake application is performed through either
displacement or hybrid feedback at the manufacturer's choosing. The
subject vehicle brake application procedures are consistent with the
manual brake applications defined in NHTSA's NCAP test procedures for
DBS performance assessment. The procedure is to begin with the subject
vehicle brake pedal in its natural resting position with no preload or
position offset.
Displacement Feedback Procedure
For the displacement feedback procedure, the commanded brake pedal
position is the brake pedal position that results in a mean
deceleration of 0.4 g in the absence of AEB system activation. The mean
deceleration is the deceleration over the time from the pedal achieving
the commanded position to 250 ms before the vehicle comes to a stop.
The pedal displacement controller depresses the pedal at a rate of 254
mm/s 25.4 mm/s to the commanded brake pedal position. The
standard allows for the pedal displacement controller to overshoot the
commanded position by any amount up to 20 percent. In the event of an
overshoot, it may be corrected within 100 ms. The achieved brake pedal
position is any position within 10 percent of the commanded position
from 100 ms after pedal displacement occurs and any overshoot is
corrected.
Hybrid Brake Pedal Feedback Procedure
For the hybrid brake pedal feedback procedure, the commanded brake
pedal application is the brake pedal position and a subsequent
commanded brake pedal force that results in a mean deceleration of 0.4
g in the absence of AEB system activation. The hybrid brake pedal
application procedure follows the displacement application procedure,
but instead of maintaining the achieved brake pedal displacement, the
controller starts to control the force applied to the brake pedal (100
ms after pedal displacement occurs and any overshoot is corrected). The
hybrid controller applies a pedal force of at least 11.1 N and
maintains the pedal force within 10 percent of the commanded brake
pedal force from 350 ms after commended pedal displacement occurs and
any overshoot is corrected, until test completion.
Force Feedback Procedure
For the force feedback procedure, the commanded brake pedal
application is the brake pedal force that results in a mean
deceleration of 0.4 g in the absence of AEB system activation. The mean
deceleration is the deceleration over the time from when the commanded
brake pedal force is first achieved to 250 ms before the vehicle comes
to a stop. The force controller achieves the commanded brake pedal
force within 250 ms. The application rate is unrestricted. The force
controller may overshoot the commanded force by up to 20 percent. If
such an overshoot occurs, it is corrected within 250 ms from when the
commanded force is first achieved. The force controller applies a pedal
force of at least 11.1 N from the onset of the brake application until
the end of the test.

B. Appendix B: Description of the PAEB Test Procedures

Test Parameters
The PAEB performance tests require a vehicle to avoid a collision
with a pedestrian test device by applying the brakes automatically
under certain test-track scenarios during daylight and darkness (with
lower beam and with upper beams activated). Similar to the lead vehicle
AEB performance test requirements, NHTSA adopted a no-contact
requirement as a performance metric. The test scenarios for PAEB
evaluation fall into three groups of scenarios based on the actions of
the pedestrian test device--crossing path, stationary and along path.
For each test conducted under the testing scenarios, NHTSA adopted the
following options within those testing scenarios: (1) pedestrian
crossing (right or left) relative to an approaching subject vehicle,
(2) subject vehicle overlap (25% or 50%), (3) pedestrian obstruction
(Yes/No), and (4) pedestrian speed stationary, walking, or
running(VP). Further parameters when approaching a
pedestrian are selected from a subject vehicle speed range
(VSV) and the lighting condition (daylight, lower beams or
upper beams). As opposed to lead vehicle AEB track testing, manual
brake application by the driver is not a parameter of the test
scenarios for PAEB.
Similarly to the lead vehicle AEB testing, NHTSA specifies that the
travel path in each of the test scenarios be straight. For PAEB
testing, the intended travel path of the subject vehicle is a straight
line originating at the location corresponding to a headway of
L0.
NHTSA specifies that if the road surface is marked with a single or
double lane line, the intended travel path be parallel to, and 1.8 m
from the inside of the closest line. If the road surface is marked with
two lane lines bordering the lane, the intended travel path is centered
between the two lines.
For each PAEB test run, the headway (L0), in meters, between the
front plane of the subject vehicle and a parallel contact plane on the
pedestrian test mannequin providing 4.0 seconds time to collision (TTC)
is calculated. L0 is determined with the following equation where VSV
is the speed of the subject vehicle in m/s and VP-y is the component of
speed of the pedestrian test mannequin in m/s in the direction of the
intended travel path:

L0 = TTC0 x (VSV-VP-y)
TTC0 = 4.0
Overlap describes the location of the point on the front of the
subject vehicle that would make contact with the

[[Page 39777]]

pedestrian test mannequin (PTM) if no braking occurred and is the
percentage of the subject vehicle's overall width that the pedestrian
test mannequin traverses. It identifies the point on the subject
vehicle that would contact a test mannequin within the subject vehicle
travel path if the subject vehicle were to maintain its speed without
braking, and it is measured from the right or the left (depending on
the side of the subject vehicle where the pedestrian test mannequin
originates).
Pedestrian Crossing Path
Test Parameters--Unobstructed From the Right
The unobstructed crossing path from the right scenario consists of
the subject vehicle traveling straight at a constant speed towards the
adult PTM, which enters its travel path (perpendicular to the vehicle's
travel path) from the right side of the vehicle. The subject vehicle
must be able to avoid contact with the pedestrian test mannequin
crossing its path. NHTSA specifies testing the unobstructed crossing
path scenario from the right with a 25% and 50% overlap during daylight
and a 50% overlap for darkness with independent tests with the lower
and upper beams activated. The subject vehicle testing speed is any
speed between 10 km/h and 60 km/h, while the PTM speed is 5km/h.
Pedestrian Test Mannequin--Unobstructed From the Right
An adult PTM is used for this scenario and NHTSA specifies that the
PTM is to be secured to a moving apparatus so that it faces the
direction of motion at 4.0 0.1 m to the right of the
subject vehicle's intended travel path. The PTM's leg articulation is
to start on apparatus movement and stops when the apparatus stops. The
PTM speed is 5 km/h.
Test Parameters--Unobstructed From the Left
The unobstructed crossing path from the left scenario consists of
the subject vehicle traveling straight at a constant speed towards the
adult PTM, which enters its travel path (perpendicular to the vehicle's
travel path) from the left side of the vehicle. The subject vehicle
must be able to avoid contact with the pedestrian test mannequin
crossing its path. NHTSA will test the unobstructed crossing path
scenario from the left with a 50% overlap during daylight. The subject
vehicle testing speed is any speed between 10 km/h and 60 km/h, while
the PTM speed is 8 km/h.
Pedestrian Test Mannequin--Unobstructed From the Left
An adult PTM is used for this scenario, and NHTSA specifies that
the PTM be secured to a moving apparatus so that it faces the direction
of motion at 6.0 0.1 m to the left of the intended travel
path. The PTM's leg articulation is to start on apparatus movement and
stops when the apparatus stops. As this simulates a running adult
pedestrian, the PTM speed is 8 km/h.
Test Parameters--Obstructed From the Right
The obstructed crossing path from the right scenario consists of
the subject vehicle traveling straight at a constant speed towards a
child PTM, which enters its travel path (perpendicular to the travel
path) from the right side of the vehicle. The child PTM crosses the
subject vehicle's travel path from in front of two stopped VTDs. The
VTDs are parked to the right of the subject vehicle's travel path, in
the adjacent lane, at 1.0 m (3 ft) from the side of the subject vehicle
(tangent with the right outermost point of the subject vehicle when the
subject vehicle is in the intended travel path). The VTDs are parked
one after the other and are facing in the same direction as the subject
vehicle. One VTD is directly behind the other, separated by 1.0 0.1 m. The subject vehicle must be able to avoid contact with
the child PTM crossing its path. NHTSA specifies testing this scenario
with a 50% overlap during daylight. The subject vehicle testing speed
is any speed between 10 km/h and 50 km/h, while the child PTM speed is
5 km/h.
Pedestrian Test Mannequin--Obstructed From the Right
A child PTM is used for the obstructed scenario. NHTSA specifies
that the child PTM is secured to a moving apparatus so that it faces
the direction of motion at 4.0 0.1 m to the right of the
intended travel path. The PTM's leg articulation is to start on
apparatus movement and stops when the apparatus stops. This scenario
simulates a running child pedestrian and the child PTM speed is 5 km/h.
Test Conduct Prior to FCW or Vehicle Braking Onset
NHTSA specifies that, as the subject vehicle approaches the
crossing path of the PTM, beginning when the headway corresponds to
L0, the subject vehicle speed be maintained within 1.6 km/h
of the test speed with minimal and smooth accelerator pedal inputs.
Furthermore, beginning when the headway corresponds to L0,
the subject vehicle heading is to be maintained with minimal steering
input such that the subject vehicle travel path does not deviate more
than 0.3 m laterally from the intended travel path and the subject
vehicle's yaw rate does not exceed 1.0 deg/s. Prior to the
start of a test trial, as long as the specified initialization
procedure is executed, a subject vehicle may be driven under any
conditions including any speed and direction, and on any road surface,
for any elapsed time prior to reaching the point where a test trial
begins. For all tests, there is no specific limitations on how a
subject vehicle is driven prior to the start of a test trail, in the
same manner as for the lead vehicle trials.
The PTM apparatus is to be triggered at a time such that the
pedestrian test mannequin meets the intended overlap. The agency
specifies that the PTM achieve its intended speed within 1.5 m after
the apparatus begins to move and maintains its intended speed within
0.4 km/h until the test completion criteria is satisfied.
Test Conduct After Either FCW or Vehicle Braking Onset
NHTSA specifies that after FCW or vehicle braking onset, the
subject vehicle's accelerator pedal is released at any rate such that
it is fully released within 500 ms. This action is omitted for vehicles
with cruise control active.
During testing, no manual brake application is permitted and the
PTM continues to move until one of the test completion criteria is
satisfied.
Test Completion Criteria
NHTSA specifies that any test run is complete when the subject
vehicle comes to a complete stop without making contact with the PTM,
when the PTM is no longer in the forward path of the subject vehicle,
or when the subject vehicle makes contact with the PTM.
Stationary Pedestrian
Test Parameters
The stationary pedestrian scenario consists of the subject vehicle
traveling straight at a constant speed towards the adult PTM, which is
stationary at an overlap of 25%, facing away from the approaching
subject vehicle. The subject vehicle must be able to avoid contact with
the stationary PTM during daylight and darkness with lower beam and
upper beam. The subject vehicle testing speed is any speed between 10
km/h and 55 km/h.
Pedestrian Test Mannequin
An adult PTM is used for this scenario and NHTSA specifies that the
PTM be stationary and face away from

[[Page 39778]]

the subject vehicle. The pedestrian test mannequin legs remain still.
Test Conduct Prior to FCW or Vehicle Braking Onset
NHTSA specifies that as the subject vehicle approaches the
stationary PTM, beginning when the headway corresponds to
L0, the subject vehicle speed be maintained within 1.6 km/h
of the test speed with minimal and smooth accelerator pedal inputs.
Furthermore, beginning when the headway corresponds to L0,
the subject vehicle heading is to be maintained with minimal steering
input such that the subject vehicle travel path does not deviate more
than 0.3 m laterally from the intended travel path and the subject
vehicle's yaw rate does not exceed 1.0 deg/s. Similarly to
the other tests, the subject vehicle may be driven under any conditions
including any speed and direction, and on any road surface, for any
elapsed time prior to reaching the point where a test trial begins.
Test Conduct After Either FCW or Vehicle Braking Onset
NHTSA specifies that after FCW or vehicle braking onset, the
subject vehicle's accelerator pedal is released at any rate such that
it is fully released within 500 ms. This action is omitted for vehicles
with cruise control active. No manual braking is permitted during
testing until one of the test completion criteria is satisfied.
Test Completion Criteria
NHTSA specifies that any test run is complete when the subject
vehicle comes to a complete stop without making contact with the PTM or
when the subject vehicle makes contact with the PTM.
Pedestrian Moving Along the Path
Test Parameters
The pedestrian moving along path scenario consists of the subject
vehicle traveling straight at a constant speed towards an adult PTM
moving away from the vehicle. The PTM is moving at 5 km/h at an overlap
of 25%, facing away on the same travel path as the vehicle. The PTM's
movement is parallel to and in the same direction as the subject
vehicle. The subject vehicle must be able to avoid contact with the
moving PTM during daylight and darkness with lower beam and upper beam.
The subject vehicle testing speed is any speed between 10 km/h and 65
km/h.
Test Conduct Prior to FCW or Vehicle Braking Onset
NHTSA specifies that as the subject vehicle approaches the moving
PTM, beginning when the headway corresponds to L0, the
subject vehicle speed is maintained within 1.6 km/h of the test speed
with minimal and smooth accelerator pedal inputs. Furthermore,
beginning when the headway corresponds to L0, the subject
vehicle heading is to be maintained with minimal steering input such
that the subject vehicle travel path does not deviate more than 0.3 m
laterally from the intended travel path and the subject vehicle's yaw
rate does not exceed 1.0 deg/s. Similarly to the other
tests the subject vehicle may be driven under any conditions including
any speed and direction, and on any road surface, for any elapsed time
prior to reaching the point where a test trial begins.
The PTM is to be secured to a moving apparatus triggered any time
after the distance between the front plane of the subject vehicle and a
parallel contact plane on the pedestrian test mannequin corresponds to
L0. The specifications state that the PTM achieve its
intended speed within 1.5 m after the apparatus begins to move and
maintain its intended speed within 0.4 km/h until one of the test
completion criteria is satisfied.
Test Conduct After Either FCW or Vehicle Braking Onset
NHTSA specifies that after FCW or vehicle braking onset, the
subject vehicle's accelerator pedal is released at any rate such that
it is fully released within 500 ms. This action is omitted for vehicles
with cruise control active. No manual braking is permitted during
testing until one of the test completion criteria is satisfied.
Test Completion Criteria
NHTSA specifies that any test run is complete when the subject
vehicle slows to a speed below that of the PTM without making contact
with the PTM, or when the subject vehicle makes contact with the PTM.

C. Appendix C: Description of the False Activation Test Procedures

Test Parameters
Headway Calculation
NHTSA specifies that for each test run conducted, the headway (L0,
L2.1, L1.1), in meters, between the front plane of the subject vehicle
and either the steel trench plate's leading edge or the rearmost plane
normal to the centerline of the vehicle test devices providing a 5.0
second, 2.1 second, and 1.1 second time to collision (TTC) is
calculated. L0, L2.1, and L1.1 are determined with the following
equation where VSV is the speed of the subject vehicle in m/s:

Lx = TTCx x (VSV) m
TTC 0 = 5.0 s
TTC 2.1 = 2.1 s
TTC 1.1 = 1.1 s
Steel Trench Plate
Test Parameters
The steel trench plate false activation scenario involves the
subject vehicle approaching at 80 km/h a steel plate, commonly used in
road construction, placed on the surface of a test track in its
intended travel path. The steel trench plate is positioned flat on the
test surface so that its longest side is parallel to the vehicle's
intended travel path and horizontally centered on the vehicle's
intended travel path. The steel plate presents no imminent danger, and
the subject vehicle can safely travel over the plate without harm.
NHTSA specifies testing with and without manual brake application.
Test Conduct
The procedure states that as the subject vehicle approaches the
steel trench plate, the subject vehicle speed shall be maintained
within 1.6 km/h of the test speed with minimal and smooth accelerator
pedal inputs beginning when the headway corresponds to L0.
Furthermore, beginning when the headway corresponds to L0,
the subject vehicle heading is to be maintained with minimal steering
input such that the subject vehicle travel path does not deviate more
than 0.3 m laterally from the intended travel path and the subject
vehicle's yaw rate does not exceed 1.0 deg/s. If an FCW
occurs, the subject vehicle's accelerator pedal is released at any rate
such that it is fully released within 500 ms. This action is omitted
for tests performed with the subject vehicle's cruise control active.
For testing without manual brake application, no manual brake
application is made until one of the test completion criteria is
satisfied. For testing with manual brake application, the subject
vehicle's accelerator pedal, if not already released, is released when
the headway corresponds to L2.1 at any rate such that it is
fully released within 500 ms. The service brake application occurs at
headway L1.1.
Test Completion Criteria
The test run is complete when the subject vehicle comes to a stop
prior to crossing over the leading edge of the steel trench plate or
when the subject vehicle crosses over the leading edge of the steel
trench plate.

[[Page 39779]]

Pass-through Test
Test Parameters
The pass-through test simulates the subject vehicle approaching at
80 km/h vehicle test devices secured in a stationary position parallel
to one another with a lateral distance of 4.5 m 0.1 m
between the vehicles' closest front wheels. The centerline between the
two vehicles is parallel to the intended travel path and the travel
path is free of obstacles. NHTSA tests with and without manual brake
application.
Test Conduct
The procedure states that as the subject vehicle approaches the gap
between the two vehicle test devices, beginning when the headway
corresponds to L0, the subject vehicle speed be maintained
within 1.6 km/h of the test speed with minimal and smooth accelerator
pedal inputs. Furthermore, beginning when the headway corresponds to
L0, the subject vehicle heading is to be maintained with
minimal steering input such that the subject vehicle travel path does
not deviate more than 0.3 m laterally from the intended travel path and
the subject vehicle's yaw rate does not exceed 1.0 deg/s.
If an FCW occurs, the subject vehicle's accelerator pedal is released
at any rate such that it is fully released within 500 ms. This action
is omitted for vehicles with cruise control active.
For testing without manual brake application, no manual brake
application is made until one of the test completion criteria is
satisfied. For testing with manual brake application, the subject
vehicle's accelerator pedal, if not already released, is released when
the headway corresponds to L2.1 at any rate such that it is
fully released within 500 ms. The service brake application occurs at
headway L1.1.
Test Completion Criteria
The test run is complete when the subject vehicle comes to a stop
prior to its rearmost point passing the vertical plane connecting the
forwardmost point of the vehicle test devices or when the rearmost
point of the subject vehicle passes the vertical plane connecting the
forwardmost point of the vehicle test devices.

List of Subjects

49 CFR Part 571

Imports, Incorporation by reference, Motor vehicle safety, Motor
vehicles, Rubber and rubber products.

49 CFR Part 595

Motor vehicle safety, Motor vehicles.

49 CFR Part 596

Automatic emergency braking, Incorporation by reference, Motor
vehicles, Motor vehicle safety, Test devices.
In consideration of the foregoing, NHTSA amends 49 CFR chapter V as
follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

0
1. The authority citation for part 571 continues to read as follows:

Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166;
delegation of authority at 49 CFR 1.95.

0
2. Amend Sec. 571.5 by:
0
a. Revising paragraph (d)(35);
0
b. Redesignating paragraphs (l)(49) and (50) as paragraphs (l)(50) and
(51), respectively; and
0
c. Adding new paragraph (l)(49).
The revision and addition read as follows:

Sec. 571.5 Matter incorporated by reference.

* * * * *
(d) * * *
(35) ASTM E1337-19, ``Standard Test Method for Determining
Longitudinal Peak Braking Coefficient (PBC) of Paved Surfaces Using
Standard Reference Test Tire,'' approved December 1, 2019, into
Sec. Sec. 571.105; 571.121; 571.122; 571.126; 571.127; 571.135;
571.136; 571.500.
* * * * *
(l) * * *
(49) SAE J2400, ``Human Factors in Forward Collision Warning
Systems: Operating Characteristics and User Interface Requirements,''
August 2003 into Sec. 571.127.
* * * * *

0
3. Add Sec. 571.127 to read as follows:

Sec. 571.127 Standard No. 127; Automatic emergency braking systems
for light vehicles.

S1. Scope. This standard establishes performance requirements for
automatic emergency braking (AEB) systems for light vehicles.
S2. Purpose. The purpose of this standard is to reduce the number
of deaths and injuries that result from crashes in which drivers do not
apply the brakes or fail to apply sufficient braking power to avoid or
mitigate a crash.
S3. Application. This standard applies to passenger cars and to
multipurpose passenger vehicles, trucks, and buses with a gross vehicle
weight rating (GVWR) of 4,536 kilograms (10,000 pounds) or less.
S4. Definitions.
Adaptive cruise control system is an automatic speed control system
that allows the equipped vehicle to follow a lead vehicle at a pre-
selected gap by controlling the engine, power train, and service
brakes.
Ambient illumination is the illumination as measured at the test
surface, not including any illumination provided by the subject
vehicle.
Automatic emergency braking (AEB) system is a system that detects
an imminent collision with vehicles, objects, and road users in or near
the path of a vehicle and automatically controls the vehicle's service
brakes to avoid or mitigate the collision.
Brake pedal application onset is when 11 N of force has been
applied to the brake pedal.
Forward collision warning is an auditory and visual warning
provided to the vehicle operator by the AEB system that is designed to
induce immediate forward crash avoidance response by the vehicle
operator.
Forward collision warning onset is the first moment in time when a
forward collision warning is provided.
Headway is the distance between the subject vehicle's frontmost
plane normal to its centerline and as applicable: the vehicle test
device's rearmost plane normal to its centerline; a parallel contact
plane (to the subject vehicle's frontmost plane) on the pedestrian test
mannequin; and the leading edge of the steel trench plate.
Lead vehicle is a vehicle test device facing the same direction and
preceding a subject vehicle within the same travel lane.
Lead vehicle braking onset is the point at which the lead vehicle
achieves a deceleration of 0.05 g due to brake application.
Masked threshold is the quietest level of a signal that can be
perceived in the presence of noise.
Pedestrian test mannequin is a device used during AEB testing, when
approaching pedestrians, meeting the specifications of subpart B of 49
CFR part 596.
Small-volume manufacturer means an original vehicle manufacturer
that produces or assembles fewer than 5,000 vehicles annually for sale
in the United States.
Steel trench plate is a rectangular steel plate often used in road
construction to temporarily cover sections of pavement unsafe to drive
over directly.
Subject vehicle is the vehicle under examination for compliance
with this standard.
Travel path is the path projected onto the road surface of a point
located at the intersection of the subject vehicle's frontmost vertical
plane and

[[Page 39780]]

longitudinal vertical center plane, as the subject vehicle travels
forward.
Subject vehicle braking onset is the point at which the subject
vehicle achieves a deceleration of 0.15 g due to the automatic control
of the service brakes.
Vehicle test device is a device meeting the specifications set
forth in subpart C of 49 CFR part 596.
S5. Requirements.
(a) Except as provided in S5(b), vehicles manufactured on or after
September 1, 2029 must meet the requirements of this standard.
(b) The requirements of S5(a) do not apply to small-volume
manufacturers, final-stage manufacturers, and alterers until one year
after the dates specified in S5(a).
S5.1. Requirements when approaching a lead vehicle.
S5.1.1. Forward collision warning. A vehicle is required to have a
forward collision warning system, as defined in S4 that provides an
auditory and visual signal to the driver of an impending collision with
a lead vehicle. The system must operate under the conditions specified
in S6 when traveling at any forward speed that is greater than 10 km/h
(6.2 mph) and less than 145 km/h (90.1 mph).
(a) Auditory signal.
(1) The auditory signal must have a high fundamental frequency of
at least 800 Hz.
(2) The auditory signal must have a tempo in the range of 6-12
pulses per second and a duty cycle in the range of 0.25-0.95.
(3) The auditory signal must have a minimum intensity of 15-30 dB
above the masked threshold.
(4) In-vehicle audio that is not related to a safety purpose or
safety system (i.e., entertainment and other audio content not related
to or essential for safe performance of the driving task) must be
muted, or reduced in volume to within 5 dB of the masked threshold
during presentation of the FCW auditory signal.
(b) Visual signal.
(1) The visual signal must be located within an ellipse that
extends 18 degrees vertically and 10 degrees horizontally of the driver
forward line of sight based on the forward-looking eye midpoint
(Mf) as described in S14.1.5. of Sec. 571.111.
(2) The visual signal must include the crash pictorial symbol in
SAE J2400, 4.1.16, incorporated by reference (see Sec. 571.5).
(3) The visual signal symbol must be red in color and steady
burning.
S5.1.2. Automatic emergency braking. A vehicle is required to have
an automatic emergency braking system, as defined in S4, that applies
the service brakes automatically when a collision with a lead vehicle
is imminent. The system must operate under the conditions specified in
S6 when the vehicle is traveling at any forward speed that is greater
than 10 km/h (6.2 mph) and less than 145 km/h (90.1 mph).
S5.1.3. Performance test requirements. The vehicle must provide a
forward collision warning and subsequently apply the service brakes
automatically when a collision with a lead vehicle is imminent such
that the subject vehicle does not collide with the lead vehicle when
tested using the procedures in S7 under the conditions specified in S6.
The forward collision warning is not required if adaptive cruise
control is engaged.
S5.2. Requirements when approaching pedestrians.
S5.2.1. Forward collision warning. A vehicle is required to have a
forward collision warning system, as defined in S4, that provides an
auditory and visual signal to the driver of an impending collision with
a pedestrian. The system must operate under the conditions specified in
S6 when the vehicle is traveling at any forward speed that is greater
than 10 km/h (6.2 mph) and less than 73 km/h (45.3 mph). The forward
collision warning system must meet the auditory signal and visual
signal requirements specified in S5.1.1.
S5.2.2. Automatic emergency braking. A vehicle is required to have
an automatic emergency braking system, as defined in S4, that applies
the service brakes automatically when a collision with a pedestrian is
imminent when the vehicle is under the conditions specified in S6 and
is traveling at any forward speed that is greater than 10 km/h (6.2
mph) and less than 73 km/h (45.3 mph).
S5.2.3. Performance test requirements. The vehicle must provide a
forward collision warning and apply the brakes automatically such that
the subject vehicle does not collide with the pedestrian test mannequin
when tested using the procedures in S8 under the conditions specified
in S6.
S5.3. False activation. The vehicle must not automatically apply
braking that results in peak additional deceleration that exceeds what
manual braking would produce by 0.25 g or greater, when tested using
the procedures in S9 under the conditions specified in S6.
S5.4. Malfunction detection and controls.
S5.4.1 The system must continuously detect system malfunctions,
including performance degradation caused solely by sensor obstructions.
If the system detects a malfunction, or if the system adjusts its
performance such that it will not meet the requirements specified in
S5.1, S5.2, or S5.3, the system must provide the vehicle operator with
a telltale notification.
S5.4.2 Except as provided in S5.4.2.1 and S5.4.2.2, the
manufacturer must not provide a control that will place the AEB system
in a mode or modes in which it will no longer satisfy the performance
requirements of S5.1, S5.2, and S5.3.
S5.4.2.1 The manufacturer may provide a control to allow AEB
deactivation that is securely activated, provided the manufacturer
enables such activation exclusively in a vehicle owned by a law
enforcement agency.
S5.4.2.2 The manufacturer may allow AEB deactivation to occur
during low-range four-wheel drive configurations, when the driver
selects ``tow mode,'' or when another vehicle system is activated that
will have a negative ancillary impact on AEB operation.
S5.4.3 The vehicle's AEB system must always return to the
manufacturer's original default AEB mode that satisfies the
requirements of S5.1, S5.2, and S5.3 at the initiation of each new
ignition cycle, unless the vehicle is in a low-range four-wheel drive
configuration selected by the driver on the previous ignition cycle
designed for low-speed, off-road driving.
S6. Test conditions.
S6.1. Environmental conditions.
S6.1.1. Temperature. The ambient temperature is any temperature
between 0 [deg]C and 40 [deg]C.
S6.1.2. Wind. The maximum wind speed is no greater than 10 m/s (22
mph) during lead vehicle avoidance tests and 6.7 m/s (15 mph) during
pedestrian avoidance tests.
S6.1.3. Ambient lighting.
(a) Daylight testing.
(1) The ambient illumination on the test surface is any level at or
above 2,000 lux.
(2) Testing is not performed while driving toward or away from the
sun such that the horizontal angle between the sun and a vertical plane
containing the centerline of the subject vehicle is less than 25
degrees and the solar elevation angle is less than 15 degrees.
(b) Dark testing.
(1) The ambient illumination on the test surface is any level at or
below 0.2 lux.
(2) Testing is performed under any lunar phase.
(3) Testing is not performed while driving toward the moon such
that the horizontal angle between the moon and a vertical plane
containing the centerline of the subject vehicle is less

[[Page 39781]]

than 25 degrees and the lunar elevation angle is less than 15 degrees.
S6.1.4. Precipitation. Testing is not conducted during periods of
precipitation or when visibility is affected by fog, smoke, ash, or
other particulate.
S6.2. Road conditions.
S6.2.1. Test Track surface and construction. The tests are
conducted on a dry, uniform, solid-paved surface. Surfaces with debris,
irregularities, or undulations, such as loose pavement, large cracks,
or dips may not be used.
S6.2.2. Surface friction. The road test surface produces a peak
friction coefficient (PFC) of 1.02 when measured using an ASTM F2493
standard reference test tire, in accordance with ASTM E1337-19
(incorporated by reference, see Sec. 571.5), at a speed of 64 km/h (40
mph), without water delivery.
S6.2.3. Slope. The test surface has any consistent slope between 0
percent and 1 percent.
S6.2.4. Markings. The road surface within 2 m of the intended
travel path is marked with zero, one, or two lines of any configuration
or color. If one line is used, it is straight. If two lines are used,
they are straight, parallel to each other, and at any distance from 2.7
m to 4.5 m apart.
S6.2.5. Obstructions. Testing is conducted such that the vehicle
does not travel beneath any overhead structures, including but not
limited to overhead signs, bridges, or gantries. No vehicles,
obstructions, or stationary objects are within 7.4 m of either side of
the intended travel path except as specified.
S6.3. Subject vehicle conditions.
S6.3.1. Malfunction notification. Testing is not conducted while
the AEB malfunction telltale specified in S5.4 is illuminated.
S6.3.2. Sensor obstruction. All sensors used by the system and any
part of the vehicle immediately ahead of the sensors, such as plastic
trim, the windshield, etc., are free of debris or obstructions.
S6.3.3. Tires. The vehicle is equipped with the original tires
present at the time of initial sale. The tires are inflated to the
vehicle manufacturer's recommended cold tire inflation pressure(s)
specified on the vehicle's placard or the tire inflation pressure
label.
S6.3.4. Brake burnish.
(a) Vehicles subject to Sec. 571.105 are burnished in accordance
with S7.4 of Sec. 571.105.
(b) Vehicles subject to Sec. 571.135 are burnished in accordance
with S7.1 of Sec. 571.135.
S6.3.5. Brake temperature. The average temperature of the service
brakes on the hottest axle of the vehicle during testing, measured
according to S6.4.1 of Sec. 571.135, is between 65[deg]C and 100[deg]C
prior to braking.
S6.3.6. Fluids. All non-consumable fluids for the vehicle are at
100 percent capacity. All consumable fluids are at any level from 5 to
100 percent capacity.
S6.3.7. Propulsion battery charge. The propulsion batteries are
charged at any level from 5 to 100 percent capacity.
S6.3.8. Cruise control. Cruise control, including adaptive cruise
control, is configured under any available setting.
S6.3.9. Adjustable forward collision warning. Forward collision
warning is configured in any operator-configurable setting.
S6.3.10. Engine braking. A vehicle equipped with an engine braking
system that is engaged and disengaged by the operator is tested with
the system in any selectable configuration.
S6.3.11. Regenerative braking. Regenerative braking is configured
under any available setting.
S6.3.12. Headlamps.
(a) Daylight testing is conducted with the headlamp control in any
selectable position.
(b) Darkness testing is conducted with the vehicle's lower beams
active and separately with the vehicle's upper beams active.
(c) Prior to performing darkness testing, headlamps are aimed
according to the vehicle manufacturer's instructions. The weight of the
loaded vehicle at the time of headlamp aiming is within 10 kg of the
weight of the loaded vehicle during testing.
S6.3.13. Subject vehicle loading. The vehicle load, which is the
sum of any vehicle occupants and any test equipment and
instrumentation, does not exceed 277 kg. The load does not cause the
vehicle to exceed its GVWR or any axle to exceed its GAWR.
S6.3.14. AEB system initialization. The vehicle is driven at a
speed of 10 km/h or higher for at least one minute prior to testing,
and subsequently the starting system is not cycled off prior to
testing.
S6.4. Equipment and test devices.
S6.4.1. The vehicle test device is specified in 49 CFR part 596,
subpart C. Local fluttering of the lead vehicle's external surfaces
does not exceed 10 mm perpendicularly from the reference surface, and
distortion of the lead vehicle's overall shape does not exceed 25 mm in
any direction.
S6.4.2. Adult pedestrian test mannequin is specified in 49 CFR part
596, subpart B.
S6.4.3. Child pedestrian test mannequin is specified in 49 CFR part
596, subpart B.
S6.4.4. The steel trench plate used for the false activation test
has the dimensions 2.4 m x 3.7 m x 25 mm and is made of ASTM A36 steel.
Any metallic fasteners used to secure the steel trench plate are flush
with the top surface of the steel trench plate.
S7. Testing when approaching a lead vehicle.
S7.1. Setup.
(a) The testing area is set up in accordance with figure 2 to this
section.
(b) Testing is conducted during daylight.
(c) For reference, table 1 to S7.1 specifies the subject vehicle
speed (VSV), lead vehicle speed (VLV), headway,
and lead vehicle deceleration for each test that may be conducted.
(d) The intended travel path of the vehicle is a straight line
toward the lead vehicle from the location corresponding to a headway of
L0.
(e) If the road surface is marked with a single or double lane
line, the intended travel path is parallel to and 1.8 m from the inside
of the closest line. If the road surface is marked with two lane lines
bordering the lane, the intended travel path is centered between the
two lines.
(f) For each test run conducted, the subject vehicle speed
(VSV), lead vehicle speed (VLV), headway, and
lead vehicle deceleration will be selected from the ranges specified in
table 1 to S7.1.

Table 1 to S7.1--Test Parameters When Approaching a Lead Vehicle
--------------------------------------------------------------------------------------------------------------------------------------------------------
Speed (km/h)
----------------------------------------- Headway (m) Lead vehicle decel (g) Manual brake application
VSV VLV
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stopped Lead Vehicle................ Any 10-80.............. 0 --.................... --.................... No.
Any 70-100............. 0 --.................... --.................... Yes.
Slower-Moving Lead Vehicle.......... Any 40-80.............. 20 --.................... --.................... No.
Any 70-100............. 20 --.................... --.................... Yes.

[[Page 39782]]

Decelerating Lead Vehicle........... 50..................... 50 Any 12-40............. Any 0.3-0.5........... No.
50..................... 50 Any 12-40............. Any 0.3-0.5........... Yes.
80..................... 80 Any 12-40............. Any 0.3-0.5........... No.
80..................... 80 Any 12-40............. Any 0.3-0.5........... Yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------

S7.2. Headway calculation. For each test run conducted under S7.3
and S7.4, the headway (L0), in meters, providing 5.0 seconds time to
collision (TTC) is calculated. L0 is determined with the following
equation where VSV is the speed of the subject vehicle in m/s and VLV
is the speed of the lead vehicle in m/s:
Equation 1 to S7.2

L0 = TTC0 x (VSV-VLV)
TTC0 = 5.0

S7.3. Stopped lead vehicle.
S7.3.1. Test parameters.
(a) For testing with no subject vehicle manual brake application,
the subject vehicle test speed is any speed between 10 km/h and 80 km/
h, and the lead vehicle speed is 0 km/h.
(b) For testing with manual brake application of the subject
vehicle, the subject vehicle test speed is any speed between 70 km/h
and 100 km/h, and the lead vehicle speed is 0 km/h.
S7.3.2. Test conduct prior to forward collision warning onset.
(a) The lead vehicle is placed stationary with its longitudinal
centerline coincident to the intended travel path.
(b) Before the headway corresponds to L0, the subject
vehicle is driven at any speed, in any direction, on any road surface,
for any amount of time.
(c) The subject vehicle approaches the rear of the lead vehicle.
(d) Beginning when the headway corresponds to L0, the
subject vehicle speed is maintained within 1.6 km/h of the test speed
with minimal and smooth accelerator pedal inputs.
(e) Beginning when the headway corresponds to L0, the
subject vehicle heading is maintained with minimal steering input such
that the travel path does not deviate more than 0.3 m laterally from
the intended travel path and the subject vehicle's yaw rate does not
exceed 1.0 deg/s.
S7.3.3. Test conduct after forward collision warning onset.
(a) The accelerator pedal is released at any rate such that it is
fully released within 500 ms. This action is omitted for vehicles
tested with cruise control active.
(b) For testing conducted with manual brake application, the
service brakes are applied as specified in S10. The onset of brake
pedal application occurs 1.0 0.1 second after forward
collision warning onset.
(c) For testing conducted without manual brake application, no
manual brake application is made until the test completion criteria of
S7.3.4 are satisfied.
S7.3.4. Test completion criteria. The test run is complete when the
subject vehicle comes to a complete stop without making contact with
the lead vehicle or when the subject vehicle makes contact with the
lead vehicle.
S7.4. Slower-moving lead vehicle.
S7.4.1. Test parameters.
(a) For testing with no subject vehicle manual brake application,
the subject vehicle test speed is any speed between 40 km/h and 80 km/
h, and the lead vehicle speed is 20 km/h.
(b) For testing with manual brake application of the subject
vehicle, the subject vehicle test speed is any speed between 70 km/h
and 100 km/h, and the lead vehicle speed is 20 km/h.
S7.4.2. Test conduct prior to forward collision warning onset.
(a) The lead vehicle is propelled forward in a manner such that the
longitudinal center plane of the lead vehicle does not deviate
laterally more than 0.3m from the intended travel path.
(b) The subject vehicle approaches the lead vehicle.
(c) Before the headway corresponds to L0, the subject
vehicle is driven at any speed, in any direction, on any road surface,
for any amount of time.
(d) Beginning when the headway corresponds to L0, the
subject vehicle and lead vehicle speed is maintained within 1.6 km/h of
the test speed with minimal and smooth accelerator pedal inputs.
(e) Beginning when the headway corresponds to L0, the
subject vehicle and lead vehicle headings are be maintained with
minimal steering input such that the subject vehicle's travel path does
not deviate more than 0.3 m laterally from the centerline of the lead
vehicle, and the yaw rate of the subject vehicle does not exceed 1.0 deg/s prior to the forward collision warning onset.
S7.4.3. Test conduct after forward collision warning onset.
(a) The subject vehicle's accelerator pedal is released at any rate
such that it is fully released within 500 ms. This action is omitted
for vehicles tested with cruise control active.
(b) For testing conducted with manual braking application, the
service brakes are applied as specified in S10. The onset of brake
pedal application is 1.0 0.1 second after the forward
collision warning onset.
(c) For testing conducted without manual braking application, no
manual brake application is made until the test completion criteria of
S7.4.4 are satisfied.
S7.4.4. Test completion criteria. The test run is complete when the
subject vehicle speed is less than or equal to the lead vehicle speed
without making contact with the lead vehicle or when the subject
vehicle makes contact with the lead vehicle.
S7.5. Decelerating lead vehicle.
S7.5.1. Test parameters.
(a) The subject vehicle test speed is 50 km/h or 80 km/h, and the
lead vehicle speed is identical to the subject vehicle test speed.
(b) [Reserved]
S7.5.2. Test conduct prior to lead vehicle braking onset.
(a) Before the 3 seconds prior to lead vehicle braking onset, the
subject vehicle is be driven at any speed, in any direction, on any
road surface, for any amount of time.
(b) Between 3 seconds prior to lead vehicle braking onset and lead
vehicle braking onset:
(1) The lead vehicle is propelled forward in a manner such that the
longitudinal center plane of the vehicle does not deviate laterally
more than 0.3 m from the intended travel path.
(2) The subject vehicle follows the lead vehicle at a headway of
any distance between 12 m and 40 m.
(3) The subject vehicle's speed is maintained within 1.6 km/h of
the test speed with minimal and smooth accelerator pedal inputs prior
to forward collision warning onset.
(4) The lead vehicle's speed is maintained within 1.6 km/h.

[[Page 39783]]

(5) The subject vehicle and lead vehicle headings are maintained
with minimal steering input such that their travel paths do not deviate
more than 0.3 m laterally from the centerline of the lead vehicle, and
the yaw rate of the subject vehicle does not exceed 1.0
deg/s until onset of forward collision warning.
S7.5.3. Test conduct following lead vehicle braking onset.
(a) The lead vehicle is decelerated to a stop with a targeted
average deceleration of any value between 0.3g and 0.5g. The targeted
deceleration magnitude is achieved within 1.5 seconds of lead vehicle
braking onset and is maintained until 250 ms prior to coming to a stop.
(b) After forward collision warning onset, the subject vehicle's
accelerator pedal is released at any rate such that it is fully
released within 500 ms. This action is omitted for vehicles with cruise
control active.
(c) For testing conducted with manual braking application, the
service brakes are applied as specified in S10. The brake pedal
application onset occurs 1.0 0.1 second after the forward
collision warning onset.
(d) For testing conducted without manual braking application, no
manual brake application is made until the test completion criteria of
S7.5.4 are satisfied.
S7.5.4. Test completion criteria. The test run is complete when the
subject vehicle comes to a complete stop without making contact with
the lead vehicle or when the subject vehicle makes contact with the
lead vehicle.
S8. Testing when approaching a pedestrian.
S8.1. Setup.
S8.1.1. General.
(a) For reference, table 2 to S8.1.1 specifies the pedestrian test
mannequin direction of travel, overlap, obstruction condition and speed
(VP), the subject vehicle speed (VSV), and the
lighting condition for each test that may be conducted.
(b) The intended travel path of the vehicle is a straight line
originating at the location corresponding to a headway of
L0.
(c) If the road surface is marked with a single or double lane
line, the intended travel path is parallel to and 1.8 m from the inside
of the closest line. If the road surface is marked with two lane lines
bordering the lane, the intended travel path is centered between the
two lines.
(d) For each test run conducted, the subject vehicle speed
(VSV) will be selected from the range specified in table 2
to S8.1.1.

Table 2 to S8.1.1--Test Parameters When Approaching a Pedestrian
--------------------------------------------------------------------------------------------------------------------------------------------------------
Speed (km/h)
Direction Overlap Obstructed ------------------------------------ Lighting condition
VSV VP
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pedestrian Crossing Road........ Right................. 25 No.................... Any 10-60......... 5 Daylight
Right................. 50 No.................... Any 10-60......... 5 Daylight
Lower Beams
Upper Beams
Left.................. 50 No.................... Any 10-60......... 8 Daylight
Right................. 50 Yes................... Any 10-50......... 5 Daylight
Stationary Pedestrian........... Right................. 25 No.................... Any 10-55......... 0 Daylight
Lower Beams
Upper Beams
Pedestrian Moving Along the Path Right................. 25 No.................... Any 10-65......... 5 Daylight
...................... .............. ...................... .................. .............. Lower Beams
Upper Beams
--------------------------------------------------------------------------------------------------------------------------------------------------------

S8.1.2. Overlap. As depicted in figure 1 to this section, overlap
describes the location of the point on the front of the subject vehicle
that would make contact with a pedestrian if no braking occurred.
Overlap is the percentage of the subject vehicle's overall width that
the pedestrian test mannequin traverses. It is measured from the right
or the left, depending on the side of the subject vehicle where the
pedestrian test mannequin originates. For each test run, the actual
overlap will be within 0.15 m of the specified overlap.
S8.1.3. Pedestrian test mannequin.
(a) For testing where the pedestrian test mannequin is secured to a
moving apparatus, the pedestrian test mannequin is secured so that it
faces the direction of motion. The pedestrian test mannequin leg
articulation starts on apparatus movement and stops when the apparatus
stops.
(b) For testing where the pedestrian test mannequin is stationary,
the pedestrian test mannequin faces away from the subject vehicle, and
the pedestrian test mannequin legs remain still.
S8.2. Headway calculation. For each test run conducted under S8.3,
S8.4, and S8.5, the headway (L0), in meters, providing 4.0
seconds time to collision (TTC) is calculated. L0 is
determined with the following equation where VSV is the
speed of the subject vehicle in m/s and VP-y is the
component of speed of the pedestrian test mannequin in m/s in the
direction of the intended travel path:
Equation 2 to S8.2
L0 = TTC0 x (VSV - VP-y)
TTC0 = 4.0

S8.3. Pedestrian crossing road.
S8.3.1. Test parameters and setup (unobstructed from right).
(a) The testing area is set up in accordance with figure 3 to this
section.
(b) Testing is conducted in the daylight or darkness conditions,
except that testing with the pedestrian at the 25 percent overlap is
only conducted in daylight conditions.
(c) Testing is conducted using the adult pedestrian test mannequin.
(d) The movement of the pedestrian test mannequin is perpendicular
to the subject vehicle's intended travel path.
(e) The pedestrian test mannequin is set up 4.0 0.1 m
to the right of the intended travel path.
(f) The intended overlap is 25 percent from the right or 50
percent.
(g) The subject vehicle test speed is any speed between 10 km/h and
60 km/h.
(h) The pedestrian test mannequin speed is 5 km/h.
S8.3.2 Test parameters and setup (unobstructed from left).
(a) The testing area is set up in accordance with figure 4 to this
section.
(b) Testing is conducted in the daylight condition.
(c) Testing is conducted using the adult pedestrian mannequin.

[[Page 39784]]

(d) The movement of the pedestrian test mannequin is perpendicular
to the intended travel path.
(e) The pedestrian test mannequin is set up 6.0 0.1 m
to the left of the intended travel path.
(f) The intended overlap is 50 percent.
(g) The subject vehicle test speed is any speed between 10 km/h and
60 km/h.
(h) The pedestrian test mannequin speed is 8 km/h.
S8.3.3. Test parameters and setup (obstructed).
(a) The testing area is set up in accordance with figure 5 to this
section.
(b) Testing is conducted in the daylight condition.
(c) Testing is conducted using the child pedestrian test mannequin.
(d) The movement of the pedestrian test mannequin is perpendicular
to the intended travel path.
(e) The pedestrian test mannequin is set up 4.0 0.1 m
to the right of the intended travel path.
(f) The intended overlap is 50 percent.
(g) Two vehicle test devices are secured in stationary positions
parallel to the intended travel path. The two vehicle test devices face
the same direction as the intended travel path. One vehicle test device
is directly behind the other separated by 1.0 0.1 m. The
frontmost plane of the vehicle test device furthermost from the subject
vehicle is located 1.0 0.1 m from the parallel contact
plane (to the subject vehicle's frontmost plane) on the pedestrian test
mannequin. The left side of each vehicle test device is 1.0 0.1 m to the right of the vertical plane parallel to the
intended travel path and tangent with the right outermost point of the
subject vehicle when the subject vehicle is in the intended travel
path.
(h) The subject vehicle test speed is any speed between 10 km/h and
50 km/h.
(i) The pedestrian test mannequin speed is 5 km/h.
S8.3.4. Test conduct prior to forward collision warning or subject
vehicle braking onset.
(a) Before the headway corresponds to L0, the subject
vehicle is driven at any speed, in any direction, on any road surface,
for any amount of time.
(b) The subject vehicle approaches the crossing path of the
pedestrian test mannequin.
(c) Beginning when the headway corresponds to L0, the
subject vehicle speed is maintained within 1.6 km/h of the test speed
with minimal and smooth accelerator pedal inputs.
(d) Beginning when the headway corresponds to L0, the
subject vehicle heading is maintained with minimal steering inputs such
that the subject vehicle's travel path does not deviate more than 0.3 m
laterally from the intended travel path, and the yaw rate of the
subject vehicle does not exceed 1.0 deg/s prior to any
automated braking onset.
(e) The pedestrian test mannequin apparatus is triggered at a time
such that the pedestrian test mannequin meets the intended overlap,
subject to the criteria in S8.1.2. The pedestrian test mannequin
achieves its intended speed within 1.5 m after the apparatus begins to
move and maintains its intended speed within 0.4 km/h until the test
completion criteria of S8.3.6 are satisfied.
S8.3.5. Test conduct after either forward collision warning or
subject vehicle braking onset.
(a) After forward collision warning or subject vehicle braking
onset, the subject vehicle's accelerator pedal is released at any rate
such that it is fully released within 500 ms. This action is omitted
for vehicles with cruise control active.
(b) No manual brake application is made until the test completion
criteria of S8.3.6 are satisfied.
(c) The pedestrian mannequin continues to move until the completion
criteria of S8.3.6 are satisfied.
S8.3.6. Test completion criteria. The test run is complete when the
subject vehicle comes to a complete stop without making contact with
the pedestrian test mannequin, when the pedestrian test mannequin is no
longer in the path of the subject vehicle, or when the subject vehicle
makes contact with the pedestrian test mannequin.
S8.4. Stationary pedestrian.
S8.4.1. Test parameters and setup.
(a) The testing area is set up in accordance with figure 6 to this
section.
(b) Testing is conducted in the daylight or darkness conditions.
(c) Testing is conducted using the adult pedestrian test mannequin.
(d) The pedestrian mannequin is set up at the 25 percent right
overlap position facing away from the approaching vehicle.
(e) The subject vehicle test speed is any speed between 10 km/h and
55 km/h.
(f) The pedestrian mannequin is stationary.
S8.4.2. Test conduct prior to forward collision warning or subject
vehicle braking onset.
(a) Before the headway corresponds to L0, the subject
vehicle is driven at any speed, in any direction, on any road surface,
for any amount of time.
(b) The subject vehicle approaches the pedestrian test mannequin.
(c) Beginning when the headway corresponds to L0, the
subject vehicle speed is maintained within 1.6 km/h of the test speed
with minimal and smooth accelerator pedal inputs.
(d) Beginning when the headway corresponds to L0, the
subject vehicle heading is maintained with minimal steering inputs such
that the subject vehicle's travel path does not deviate more than 0.3 m
laterally from the intended travel path, and the yaw rate of the
subject vehicle does not exceed 1.0 deg/s prior to any
automated braking onset.
S8.4.3. Test conduct after either forward collision warning or
subject vehicle braking onset.
(a) After forward collision warning or subject vehicle braking
onset, the subject vehicle's accelerator pedal is released at any rate
such that it is fully released within 500 ms. This action is omitted
with vehicles with cruise control active.
(b) No manual brake application is made until the test completion
criteria of S8.4.4 are satisfied.
S8.4.4. Test completion criteria. The test run is complete when the
subject vehicle comes to a complete stop without making contact with
the pedestrian test mannequin, or when the subject vehicle makes
contact with the pedestrian test mannequin.
S8.5. Pedestrian moving along the path.
S8.5.1. Test parameters and setup.
(a) The testing area is set up in accordance with figure 7 to this
section.
(b) Testing is conducted in the daylight or darkness conditions.
(c) Testing is conducted using the adult pedestrian test mannequin.
(d) The movement of the pedestrian test mannequin is parallel to
and in the same direction as the subject vehicle.
(e) The pedestrian test mannequin is set up in the 25 percent right
offset position.
(f) The subject vehicle test speed is any speed between 10 km/h and
65 km/h.
(g) The pedestrian test mannequin speed is 5 km/h.
S8.5.2. Test conduct prior to forward collision warning or subject
vehicle braking onset.
(a) Before the headway corresponds to L0, the subject
vehicle is driven at any speed, in any direction, on any road surface,
for any amount of time.
(b) The subject vehicle approaches the pedestrian test mannequin.
(c) Beginning when the headway corresponds to L0, the
subject vehicle speed is maintained within 1.6 km/h of the test speed
with minimal and smooth accelerator pedal inputs.

[[Page 39785]]

(d) Beginning when the headway corresponds to L0, the
subject vehicle heading is maintained with minimal steering inputs such
that the travel path does not deviate more than 0.3 m laterally from
the intended travel path, and the yaw rate of the subject vehicle does
not exceed 1.0 deg/s prior to any automated braking onset.
(e) The pedestrian test mannequin apparatus is triggered any time
after the distance between the front plane of the subject vehicle and a
parallel contact plane on the pedestrian test mannequin corresponds to
L0. The pedestrian test mannequin achieves its intended
speed within 1.5 m after the apparatus begins to move and maintains its
intended speed within 0.4 km/h until the test completion criteria of
S8.5.4 are satisfied.
S8.5.3. Test conduct after either forward collision warning or
subject vehicle braking onset.
(a) After forward collision warning or subject vehicle braking
onset, the subject vehicle's accelerator pedal is released at any rate
such that it is fully released within 500 ms. This action is omitted
for vehicles with cruise control active.
(b) No manual brake application is made until the test completion
criteria of S8.5.4 are satisfied.
S8.5.4. Test completion criteria. The test run is complete when the
subject vehicle slows to speed below the pedestrian test mannequin
travel speed without making contact with the pedestrian test mannequin
or when the subject vehicle makes contact with the pedestrian test
mannequin.
S9. False AEB activation.
S9.1. Headway calculation. For each test run to be conducted under
S9.2 and S9.3, the headway (L0, L2.1, L1.1), in meters, providing 5.0
seconds, 2.1 seconds, and 1.1 seconds time to collision (TTC) is
calculated. L0, L2.1, and L1.1 are determined with the
following equation where VSV is the speed of the subject
vehicle in m/s:
Equation 3 to S9.1
Lx = TTCx x (VSV)
TTC0 = 5.0
TTC2.1 = 2.1
TTC1.1 = 1.1

S9.2. Steel trench plate.
S9.2.1. Test parameters and setup.
(a) The testing area is set up in accordance with figure 8 to this
section.
(b) The steel trench plate is secured flat on the test surface so
that its longest side is parallel to the vehicle's intended travel path
and horizontally centered on the vehicle's intended travel path.
(c) The subject vehicle test speed is 80 km/h.
(d) Testing is conducted with manual brake application and without
manual brake application.
(e) Testing is conducted during daylight.
S9.2.2. Test conduct.
(a) Before the headway corresponds to L0, the subject
vehicle is driven at any speed, in any direction, on any road surface,
for any amount of time.
(b) The subject vehicle approaches the steel trench plate.
(c) Beginning when the headway corresponds to L0, the
subject vehicle speed is maintained within 1.6 km/h of the test speed
with minimal and smooth accelerator pedal inputs.
(d) Beginning when the headway corresponds to L0, the
subject vehicle heading is maintained with minimal steering input such
that the travel path does not deviate more than 0.3 m laterally from
the intended travel path, and the yaw rate of the subject vehicle does
not exceed 1.0 deg/s.
(e) If forward collision warning occurs, the subject vehicle's
accelerator pedal is released at any rate such that it is fully
released within 500 ms. This action is omitted for vehicles with cruise
control active.
(f) For tests where no manual brake application occurs, manual
braking is not applied until the test completion criteria of S9.2.3 are
satisfied.
(g) For tests where manual brake application occurs, the subject
vehicle's accelerator pedal, if not already released, is released when
the headway corresponds to L2.1 at any rate such that it is
fully released within 500 ms.
(h) For tests where manual brake application occurs, the service
brakes are applied as specified in S10. The brake application pedal
onset occurs at headway L1.1.
S9.2.3. Test completion criteria. The test run is complete when the
subject vehicle comes to a stop prior to crossing over the leading edge
of the steel trench plate or when the subject vehicle crosses over the
leading edge of the steel trench plate.
S9.3. Pass-through.
S9.3.1. Test parameters and setup.
(a) The testing area is set up in accordance with figure 9 to this
section.
(b) Two vehicle test devices are secured in a stationary position
parallel to one another with a lateral distance of 4.5 m 0.1 m between the vehicles' closest front wheels. The centerline
between the two vehicles is parallel to the intended travel path.
(c) The subject vehicle test speed is 80 km/h.
(d) Testing is conducted with manual brake application and without
manual brake application.
(e) Testing is conducted during daylight.
S9.3.2. Test conduct.
(a) Before the headway corresponds to L0, the subject
vehicle is driven at any speed, in any direction, on any road surface,
for any amount of time.
(b) The subject vehicle approaches the gap between the two vehicle
test devices.
(c) Beginning when the headway corresponds to L0, the
subject vehicle speed is maintained within 1.6 km/h with minimal and
smooth accelerator pedal inputs.
(d) Beginning when the headway corresponds to L0, the
subject vehicle heading is maintained with minimal steering input such
that the travel path does not deviate more than 0.3 m laterally from
the intended travel path, and the yaw rate of the subject vehicle does
not exceed 1.0 deg/s.
(e) If forward collision warning occurs, the subject vehicle's
accelerator pedal is released at any rate such that it is fully
released within 500 ms.
(f) For tests where no manual brake application occurs, manual
braking is not applied until the test completion criteria of S9.3.3 are
satisfied.
(g) For tests where manual brake application occurs, the subject
vehicle's accelerator pedal, if not already released, is released when
the headway corresponds to L2.1 at any rate such that it is
fully released within 500 ms.
(h) For tests where manual brake application occurs, the service
brakes are applied as specified in S10. The brake application onset
occurs when the headway corresponds to L1.1.
S9.3.3. Test completion criteria. The test run is complete when the
subject vehicle comes to a stop prior to its rearmost point passing the
vertical plane connecting the forwardmost point of the vehicle test
devices or when the rearmost point of the subject vehicle passes the
vertical plane connecting the forwardmost point of the vehicle test
devices.
S10. Subject vehicle brake application procedure.
S10.1. The procedure begins with the subject vehicle brake pedal in
its natural resting position with no preload or position offset.
S10.2. At the option of the manufacturer, either displacement
feedback, hybrid feedback, or force feedback control is used.
S10.3. Displacement feedback procedure. For displacement feedback,
the commanded brake pedal position is the brake pedal position that
results in a mean deceleration of 0.4 g in the absence of AEB system
activation.

[[Page 39786]]

(a) The mean deceleration is the deceleration over the time from
the brake pedal achieving the commanded position to 250 ms before the
vehicle comes to a stop.
(b) The pedal displacement controller displaces the brake pedal at
a rate of 254 mm/s 25.4 mm/s to the commanded brake pedal
position.
(c) The pedal displacement controller may overshoot the commanded
position by any amount up to 20 percent. If such an overshoot occurs,
it is corrected within 250 ms from when the commanded position is first
achieved.
(d) The achieved brake pedal position is any position within 10
percent of the commanded position from 250 ms after the commanded brake
pedal position is first achieved to the end of the test.
S10.4. Hybrid brake pedal feedback procedure. For hybrid brake
pedal feedback, the commanded brake pedal application is the brake
pedal position and a subsequent commanded brake pedal force that
results in a mean deceleration of 0.4 g in the absence of AEB system
activation.
(a) The mean deceleration is the deceleration over the time from
the brake pedal achieving the commanded position to 250 ms before the
vehicle comes to a stop.
(b) The hybrid controller displaces the brake pedal at a rate of
254 mm/s 25.4 mm/s to the commanded pedal position.
(c) The hybrid controller may overshoot the commanded position by
any amount up to 20 percent. If such an overshoot occurs, it is
corrected within 250 ms from then the commanded position is first
achieved.
(d) The hybrid controller begins to control the force applied to
the brake pedal and stops controlling pedal displacement within 100 ms
after the commanded brake pedal displacement occurs.
(e) The hybrid controller applies a pedal force of at least 11.1 N
from the onset of the brake application until the end of the test.
(f) The average pedal force is maintained within 10 percent of the
commanded brake pedal force from 350 ms after commended pedal
displacement occurs until test completion.
S10.5. Force feedback procedure. For force feedback, the commanded
brake pedal application is the brake pedal force that results in a mean
deceleration of 0.4 g in the absence of AEB system activation.
(a) The mean deceleration is the deceleration over the time from
when the commanded brake pedal force is first achieved to 250 ms before
the vehicle comes to a stop.
(b) The force controller achieves the commanded brake pedal force
within 250 ms. The application rate is unrestricted.
(c) The force controller may overshoot the commanded force by any
amount up to 20 percent. If such an overshoot occurs, it is corrected
within 250 ms from when the commanded force is first achieved.
(d) The force controller applies a pedal force of at least 11.1 N
from the onset of the brake application until the end of the test.
(e) The average pedal force is maintained within 10 percent of the
commanded brake pedal force from 250 ms after commended pedal force
occurs until test completion.
BILLING CODE 4910-59-P

Figure 1 to Sec. 571.127--Percentage Overlap Nomenclature
[GRAPHIC] [TIFF OMITTED] TR09MY24.030

[[Page 39787]]

Figure 2 to Sec. 571.127--Setup for Lead Vehicle Automatic Emergency
Braking
[GRAPHIC] [TIFF OMITTED] TR09MY24.031

[[Page 39788]]

Figure 3 to Sec. 571.127--Setup for Pedestrian, Crossing Path, Right
[GRAPHIC] [TIFF OMITTED] TR09MY24.032

[[Page 39789]]

Figure 4 to Sec. 571.127--Setup for Pedestrian, Crossing Path, Left
[GRAPHIC] [TIFF OMITTED] TR09MY24.033

[[Page 39790]]

Figure 5 to Sec. 571.127--Setup for Pedestrian, Obstructed
[GRAPHIC] [TIFF OMITTED] TR09MY24.034

[[Page 39791]]

Figure 6 to Sec. 571.127--Setup for Pedestrian Along-Path Stationary
[GRAPHIC] [TIFF OMITTED] TR09MY24.035

[[Page 39792]]

Figure 7 to Sec. 571.127--Setup for Pedestrian Along-Path Moving
[GRAPHIC] [TIFF OMITTED] TR09MY24.036

Figure 8 to Sec. 571.127--Steel Trench Plate
[GRAPHIC] [TIFF OMITTED] TR09MY24.037

[[Page 39793]]

Figure 9 to Sec. 571.127--Pass-through
[GRAPHIC] [TIFF OMITTED] TR09MY24.038

BILLING CODE 4910-59-C

PART 595--MAKE INOPERATIVE EXEMPTIONS

0
4. The authority citation for part 595 continues to read as follows:

Authority: 49 U.S.C. 322, 30111, 30115, 30117, 30122 and 30166;
delegation of authority at 49 CFR 1.95.

0
5. Amend Sec. 595.4 by adding the definition of ``Manufacturer'' in
alphabetical order to read as follows:

Sec. 595.4 Definitions.

* * * * *
Manufacturer is defined as it is in 49 U.S.C. 30102(a).
* * * * *

0
6. Add subpart D to read as follows:

Subpart D--Modifications to Law Enforcement Vehicles

Sec. 595.9 Automatic emergency braking.

A manufacturer, dealer, or motor vehicle repair business that
modifies a vehicle owned by a law enforcement agency to provide a means
to temporarily deactivate an AEB system is exempted from the ``make
inoperative'' prohibition in 49 U.S.C. 30122 to the extent that such
modification affects the motor vehicle's compliance with 49 CFR
571.127, S5.4.2. Modifications that would take a vehicle out of
compliance with any other Federal motor vehicle safety standards, or
portions thereof, are not covered by this exemption.

0
7. Add part 596 to read as follows.

PART 596--AUTOMATIC EMERGENCY BRAKING TEST DEVICES

Subpart A--General
Sec.
596.1 Scope.
596.2 Purpose.
596.3 Application.
596.4 Definitions.
596.5 Matter incorporated by reference.
Subpart B--Pedestrian Test Devices
596.7 Specifications for pedestrian test devices.
596.8 [Reserved]
Subpart C--Vehicle Test Device
596.9 General description.
596.10 Specifications for the vehicle test device.

Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166;
delegation of authority at 49 CFR 1.95.

Subpart A--General

Sec. 596.1 Scope.

This part describes the test devices to be used for compliance
testing of motor vehicles with motor vehicle safety standards for
automatic emergency braking.

Sec. 596.2 Purpose.

The design and performance criteria specified in this part are
intended to describe devices with sufficient precision such that
testing performed with these test devices will produce repetitive and
correlative results under similar test conditions to reflect adequately
the automatic emergency braking performance of a motor vehicle.

Sec. 596.3 Application.

This part does not in itself impose duties or liabilities on any
person. It is a description of tools that are used in compliance tests
to measure the performance of automatic emergency braking systems
required by the safety standards that refer to these tools. This part
is designed to be referenced by, and become part of, the test
procedures specified in motor vehicle safety standards, such as 49 CFR
571.127.

Sec. 596.4 Definitions.

All terms defined in section 30102 of the National Traffic and
Motor Vehicle Safety Act (49 U.S.C. chapter 301, et seq.) are used in
their statutory meaning.
Adult pedestrian test mannequin (APTM) means a test device with the
appearance and radar cross section that simulates an adult pedestrian
for the purpose of testing automatic emergency brake system
performance.
Child pedestrian test mannequin (CPTM) means a test device with the
appearance and radar cross section that stimulates a child pedestrian
for the purpose of testing automatic emergency brake system
performance.
Pedestrian test device(s) means an adult pedestrian test mannequin
and/or a child pedestrian test mannequin.
Pedestrian test mannequin carrier means a movable platform on which
an adult pedestrian test mannequin or child pedestrian test mannequin
may be attached during compliance testing.
Vehicle test device means a test device that simulates a passenger
vehicle for the purpose of testing automatic emergency brake system
performance.
Vehicle test device carrier means a movable platform on which a
lead vehicle test device may be attached during compliance testing.

Sec. 596.5 Matter incorporated by reference.

Certain material is incorporated by reference into this part with
the approval of the Director of the Federal Register under 5 U.S.C.
552(a) and 1 CFR part 51. To enforce any edition other than that
specified in this section, the National Highway Traffic Safety
Administration (NHTSA) must publish notice of change in the Federal
Register and the material must be available to the public. All approved
material is available for inspection at NHTSA and at the National
Archives and Records Administration (NARA). Contact NHTSA at: NHTSA
Office of Technical Information Services, 1200 New Jersey Avenue SE,
Washington, DC 20590; (202) 366-2588. For information on the
availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected]. The
material may be obtained from the source(s) in the following paragraph
of this section.
(a) International Organization for Standardization (ISO), 1, ch. de
la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland; phone: + 41 22
749 01 11 fax: + 41 22 733 34 30; website: https://www.iso.org/.

[[Page 39794]]

(1) ISO 3668:2017(E), Paints and varnishes--Visual comparison of
colour of paints, Third edition, 2017-05 (ISO 3668:2017); into Sec.
596.7.
(2) ISO 19206-2:2018(E), Road vehicles--Test devices for target
vehicles, vulnerable road users and other objects, for assessment of
active safety functions--Part 2: Requirements for pedestrian targets,
First edition, 2018-12 (ISO 19206-2:2018); into Sec. 596.7.
(3) ISO 19206-3:2021(E), Test devices for target vehicles,
vulnerable road users and other objects, for assessment of active
safety functions--Part 3: Requirements for passenger vehicle 3D
targets, First edition, 2021-05 (ISO 19206-3:2021); into Sec. 596.10.
(4) ISO 19206-4:2020(E), Test devices for target vehicles,
vulnerable road users and other objects, for assessment of active
safety functions -Part 4: Requirements for bicyclist targets, First
edition, 2020-11 (ISO 19206-4:2020); into Sec. 596.7.
(b) [Reserved]

Subpart B--Pedestrian Test Devices

Sec. 596.7 Specifications for pedestrian test devices.

(a) Explanation of usage. The words ``recommended,'' ``should,''
``can be,'' or ``should be'' appearing in sections of ISO 19206-2:2018
(incorporated by reference, see Sec. 596.5), referenced in this
section, are read as setting forth specifications that are used.
(b) Explanation of usage. The words ``may be,'' or ``either'' used
in connection with a set of items appearing in sections of ISO 19206-
2:2018 (incorporated by reference, see Sec. 596.5), referenced in this
section, are read as setting forth the totality of items, any one of
which may be selected by NHTSA for testing.
(c) Specifications for the pedestrian test devices--(1) General
description. The adult pedestrian test mannequin (APTM) provides a
sensor representation of a 50th percentile adult male and consist of a
head, torso, two arms and hands, and two legs and feet. The child
pedestrian test mannequin (CPTM) provides a sensor representation of a
6- to 7-year-old child and consists of a head, torso, two arms and
hands, and two legs and feet. The arms of the APTM and CPTM are
posable, but do not move during testing. The legs of the APTM and CPTM
articulate and are synchronized to the forward motion of the mannequin.
(2) Dimensions and posture. The APTM has basic body dimensions and
proportions specified in Annex A, table A.1 in ISO 19206-2:2018
(incorporated by reference, see Sec. 596.5). The CPTM has basic body
dimensions and proportions specified in Annex A, table A.1 in ISO
19206-2:2018 (incorporated by reference, see Sec. 596.5).
(3) Visual properties--(i) Head. The head has a visible hairline
silhouette by printed graphic. The hair is black as defined in Annex B
table B.2 of ISO 19206-4:2020, as tested in accordance with ISO
3668:2017 (both incorporated by reference, see Sec. 596.5).
(ii) Face. The head does not have any facial features (i.e., eyes,
nose, mouth, and ears).
(iii) Skin. The face, neck and hands have a skin colored as defined
Annex B, table B.2 of ISO 19206-4:2020 (incorporated by reference, see
Sec. 596.5).
(iv) Torso and arms. The torso and arms are black as defined in
Annex B table B.2 of ISO 19206-4:2020, as tested in accordance with ISO
3668:2017 (both incorporated by reference, see Sec. 596.5).
(v) Legs. The legs are blue as defined in Annex B table B.2 of ISO
19206-4:2020, as tested in accordance with ISO 3668:2017 (both
incorporated by reference, see Sec. 596.5).
(vi) Feet. The feet are black as defined in Annex B table B.2 of
ISO 19206-4:2020, as tested in accordance with ISO 3668:2017 (both
incorporated by reference, see Sec. 596.5).
(4) Infrared properties. The surface of the entire APTM or CPTM are
within the reflectivity ranges specified in Annex B section B.2.2 of
ISO 19206-2:2018, as illustrated in Annex B, figure B.2 (incorporated
by reference, see Sec. 596.5).
(5) Radar properties. The radar reflectivity characteristics of the
pedestrian test device approximates that of a pedestrian of the same
size when approached from the side or from behind.
(6) Radar cross section measurements. The radar cross section
measurements of the APTM and the CPTM is within the upper and lower
boundaries shown in Annex B, section B.3, figure B.6 of ISO 19206-
2:2018 when tested in accordance with the measure procedure in Annex C,
section C.3, Scenario 2 Fixed Angle Scans of ISO 19206-3:2021 with a
measurement range of 4m to 40m (incorporated by reference, see Sec.
596.5).
(7) Posture. The pedestrian test device has arms that are posable
and remain posed during testing. The pedestrian test device is equipped
with moving legs consistent with standard gait phases specified in
Section 5.6 of ISO 19206-2:2018 (incorporated by reference, see Sec.
596.5).
(8) Articulation properties. The legs of the pedestrian test device
are in accordance with, and as described in, Annex D, section D.2 and
illustrated in Figures D.1, D.2, and D.3 of ISO 19206-2:2018
(incorporated by reference, see Sec. 596.6).

Sec. 596.8 [Reserved]

Subpart C--Vehicle Test Device

Sec. 596.9 General description.

(a) The vehicle test device provides a sensor representation of a
passenger motor vehicle.
(b) The rear view of the vehicle test device contains
representations of the vehicle silhouette, a rear window, a high-
mounted stop lamp, two taillamps, a rear license plate, two rear reflex
reflectors, and two tires.

Sec. 596.10 Specifications for the vehicle test device.

(a) Explanation of usage. The words ``recommended,'' ``should,''
``can be,'' or ``should be'' appearing in sections of ISO 19206-3:2021
(incorporated by reference, see Sec. 596.5), referenced in this
section, are read as setting forth specifications that are used.
(b) Explanation of usage. The words ``may be,'' or ``either,'' used
in connection with a set of items appearing in sections of ISO 19206-
3:2021 (incorporated by reference, see Sec. 596.5), referenced in this
section, are read as setting forth the totality of items, any one of
which may be selected by NHTSA for testing.
(c) Dimensional specifications. (1) The rear silhouette and the
rear window are symmetrical about a shared vertical centerline.
(2) Representations of the taillamps, rear reflex reflectors, and
tires are symmetrical about the surrogate's centerline.
(3) The license plate representation has a width of 300 15 mm and a height of 150 15 mm and mounted with a
license plate holder angle within the range described in 49 CFR
571.108, S6.6.3.1.
(4) The vehicle test device representations are located within the
minimum and maximum measurement values specified in columns 3 and 4 of
Tables A.4 of ISO 19206-3:2021 Annex A (incorporated by reference, see
Sec. 596.5). The tire representations are located within the minimum
and maximum measurement values specified in columns 3 and 4 of Tables
A.3 of ISO 19206-3:2021 Annex A (incorporated by reference, see Sec.
596.5). The terms ``rear light'' means ``taillamp,'' ``retroreflector''
means ``reflex reflector,'' and ``high centre taillight'' means ``high-
mounted stop lamp.''

[[Page 39795]]

(d) Visual and near infrared specification. (1) The vehicle test
device rear representation colors are within the ranges specified in
Tables B.2 and B.3 of ISO 19206-3:2021 Annex B (incorporated by
reference, see Sec. 596.5).
(2) The rear representation infrared properties of the vehicle test
device are within the ranges specified in Table B.1 of ISO 19206-3:2021
Annex B (incorporated by reference, see Sec. 596.5) for wavelengths of
850 to 950 nm when measured according to the calibration and
measurement setup specified in paragraph B.3 of ISO 19206-3:2021 Annex
B (incorporated by reference, see Sec. 596.5).
(3) The vehicle test device rear reflex reflectors, and at least 50
cm\2\ of the taillamp representations are grade DOT-C2 reflective
sheeting as specified in 49 CFR 571.108, S8.2.
(e) Radar reflectivity specifications. (1) The radar cross section
of the vehicle test device is measured with it attached to the carrier
(robotic platform). The radar reflectivity of the carrier platform is
less than 0 dBm\2\ for a viewing angle of 180 degrees and over a range
of 5 to 100 m when measured according to the radar measurement
procedure specified in Section C.3 of ISO 19206-3:2021 Annex C
(incorporated by reference, see Sec. 596.5) for fixed-angle scans.
(2) The rear bumper area as shown in Table C.1 of ISO 19206-3:2021
Annex C (incorporated by reference, see Sec. 596.5) contributes to the
target radar cross section.
(3) The radar cross section is assessed using radar sensor that
operates at 76 to 81 GHz and has a range of at least 5 to 100 m, a
range gate length smaller than 0.6m, a horizontal field of view of 10
degrees or more (-3dB amplitude limit), and an elevation field of view
of 5 degrees or more (-3dB amplitude).
(4) At least 92 percent of the filtered data points of the
surrogate radar cross section for the fixed vehicle angle, variable
range measurements are within the radar cross section boundaries
defined in Section C.2.2.4 of ISO 19206-3:2021 Annex C (incorporated by
reference, see Sec. 596.5) for a viewing angle of 180 degrees when
measured according to the radar measurement procedure specified in
Section C.3 of ISO 19206-3:2021 Annex C (incorporated by reference, see
Sec. 596.5) for fixed-angle scans.
(5) Between 86 to 95 percent of the vehicle test device spatial
radar cross section reflective power is with the primary reflection
region defined in Section C.2.2.5 of ISO 19206-3:2021 Annex C
(incorporated by reference, see Sec. 596.5) when measured according to
the radar measurement procedure specified in Section C.3 of ISO 19206-
3:2021 Annex C (incorporated by reference, see Sec. 596.5) using the
angle-penetration method.

Issued in Washington, DC, under authority delegated in 49 CFR
1.95 and 501.5.
Sophie Shulman,
Deputy Administrator.
[FR Doc. 2024-09054 Filed 5-8-24; 8:45 am]
BILLING CODE 4910-59-P