[Federal Register Volume 89, Number 52 (Friday, March 15, 2024)]
[Rules and Regulations]
[Pages 18808-18831]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-05010]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 535

[NHTSA-2020-0079]
RIN 2127-AM28


Improvements for Heavy-Duty Engine and Vehicle Fuel Efficiency 
Test Procedures, and Other Technical Amendments

AGENCY: National Highway Traffic Safety Administration.

ACTION: Final rule.

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SUMMARY: The National Highway Traffic Safety Administration (NHTSA) is 
finalizing minor technical amendments to the test procedures for heavy-
duty engines and vehicles to improve accuracy and reduce testing 
burden. These amendments affect the certification procedures for fuel 
efficiency standards and related requirements. These amendments 
increase compliance flexibility, harmonize with other requirements, add 
clarity, correct errors, and streamline the regulations. Given the 
nature of these changes, NHTSA does not expect either significant 
environmental impacts or significant economic impacts for any sector.

DATES: This final rule is effective on May 14, 2024.

ADDRESSES: NHTSA has established a docket for this action under Docket 
ID: NHTSA-2020-0079. For access to the dockets to read background 
documents or comments received, go to http://www.regulations.gov, and/
or: Docket Management Facility, M-30, U.S. Department of 
Transportation, West Building, Ground Floor, Rm. W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590. The DOT Docket Management 
Facility is open between 9 a.m. and 5 p.m. Eastern Standard Time (EST), 
Monday through Friday, except Federal holidays. Please call ahead if 
you plan to drop off or pick up a document to ensure someone is 
available to assist you. The Docket Management Facility can be reached 
at (202) 366-9826 or (202) 366-9317 to arrange a drop off/pick up.

FOR FURTHER INFORMATION CONTACT: Seiar Zia, Deputy Division Chief, Fuel 
Economy Division, Office of Rulemaking, National Highway Traffic Safety 
Administration, 1200 New Jersey Avenue SE, Washington, DC 20590; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information
    A. Does this action apply to me?
    B. What action is the Agency taking?
    C. What are the incremental costs and benefits of this action?
II. Medium and Heavy-Duty Fuel Efficiency Program Technical 
Amendments
    A. Overview of the Medium and Heavy-Duty Fuel Efficiency Program
    B. Public Participation Opportunities and Summary of Comments
    C. Overview of the Final Rule
    D. Authority Citation for Part 535
    E. 49 CFR 535.1 Scope
    F. 49 CFR 535.3 Applicability
    G. 49 CFR 535.4 Definitions
    H. 49 CFR 535.5 Standards
    I. 49 CFR 535.6 Measurement and Calculation Procedures
    J. 49 CFR 535.7 Averaging, Banking, and Trading (ABT) Credit 
Program
    K. 49 CFR 535.8 Reporting and Recordkeeping Requirements
    L. 49 CFR 535.9 Enforcement Approach
    M. 49 CFR 535.10 How do manufacturers comply with fuel 
consumption standards?
III. Statutory Authority and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use
    I. National Technology Transfer and Advancement Act (NTTAA)
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Does this action apply to me?

    This action will affect companies that manufacture, sell, or import 
into the United States new heavy-duty engines and new Class 2b through 
8 trucks, including combination tractors, buses, vocational vehicles 
including municipal, commercial, recreational vehicles, and \3/4\-ton 
and 1-ton pickup trucks and vans. The heavy-duty category incorporates 
all motor vehicles with a gross vehicle weight rating of 8,501 lbs. or 
greater, and the engines that power them, except for medium-duty 
passenger vehicles covered by the corporate average fuel economy 
standards and greenhouse gas standards issued for light-duty vehicles. 
The regulations for the Medium- and Heavy-Duty Vehicle Fuel Efficiency 
Program are found at 49 CFR part 535.
    Regulated categories and entities include the following:
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    \1\ North American Industry Classification System (NAICS).

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                                                         Examples of
           Category               NAICS codes \1\        potentially
                                                      regulated entities
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Industry.....................  333618, 336111,       Motor vehicle
                                336112, 336120,       manufacturers and
                                336211, 336212,       engine
                                336611, 336911,       manufacturers.
                                336999.

[[Page 18809]]

 
Industry.....................  811111, 811112,       Commercial
                                811198, 423110.       importers of
                                                      vehicles and
                                                      vehicle
                                                      components.
Industry.....................  335312, 811198......  Alternative fuel
                                                      vehicle
                                                      converters.
Industry.....................  326199, 332431......  Portable fuel
                                                      container
                                                      manufacturers.
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    This list is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. If you have questions regarding the applicability of this 
action to a particular entity, consult the person listed in the FOR 
FURTHER INFORMATION CONTACT section.

B. What action is the Agency taking?

    This action finalizes amendments to the regulations that implement 
NHTSA's fuel efficiency standards for medium-duty and heavy-duty 
engines and vehicles. These amendments are technical in nature and 
include corrections and clarifications to a variety of existing 
regulatory provisions to improve consistency with related EPA standards 
and with NHTSA's original intent for those provisions. In other words, 
this final rule comprises a variety of small changes for multiple types 
of engines and vehicles.
    These amendments parallel similar ones in a rulemaking conducted by 
the EPA under RIN 2060-AU62.\2\ These technical amendments are intended 
to maintain alignment between EPA's Medium and Heavy-Duty Vehicle 
Greenhouse Gas Emissions and NHTSA's Fuel Efficiency Standards. The 
technical amendments in this final rule are necessary to align with the 
technical amendments finalized by EPA under the parallel rulemaking 
referenced in this paragraph.
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    \2\ NPRM published on May 12, 2020 (85 FR 28140); final rule 
published on June 29, 2021 (86 FR 34308), as corrected by notices 
published on September 23, 2021 (86 FR 52833) and October 26, 2022 
(87 FR 64864).
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    Most of the amendments being finalized in this rule will modify 
existing test procedures for medium- and heavy-duty engines and 
vehicles. These test procedure changes will improve accuracy, and in 
some cases, reduce test burden.
    Other amendments will update NHTSA's regulations to enhance the 
implementation of existing fuel efficiency standards. For example, some 
changes will reduce the likelihood that manufacturers will need to 
conduct unique certification testing for compliance with Canadian and 
CARB standards, in addition to NHTSA's standards. Some amendments will 
make it easier for manufacturers to more fully account for the fuel 
efficiency benefits of advanced fuel efficiency improving technology, 
which could provide them the opportunity to generate additional fuel 
consumption improvement values for compliance. These amendments are 
described in II.
    Additionally, as a matter of housekeeping, NHTSA is removing 
portions of its regulations that were vacated by the United States 
Court of Appeals for the District of Columbia Circuit. In November 
2021, that Court ``vacate[d] all portions of the [2016 joint NHTSA and 
EPA] rule that apply to trailers.'' Truck Trailer Mfrs. Ass'n, Inc. v. 
EPA, 17 F.4th 1198, 1200 (D.C. Cir. 2021). The underlying statute 
authorizes NHTSA to examine the fuel efficiency of and prescribe fuel 
economy standards for ``commercial medium-duty [and/or] heavy-duty on-
highway vehicles.'' 49 U.S.C. 32902(b)(1)(C); 49 U.S.C. 32902(k)(2). 
The Court reasoned that trailers do not qualify as ``vehicles'' when 
that term is used in the fuel economy context because trailers are 
motorless and use no fuel. Truck Trailer Mfrs. Ass'n, Inc., 17 F.4th at 
1200, 1204-08. Accordingly, the Court held that NHTSA does not have the 
authority to regulate the fuel economy of trailers. Id. at 1208.\3\ As 
a result, NHTSA is removing the vacated trailer provisions from its 
regulations.
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    \3\ For similar reasons, the Court also held that the statute 
authorizing EPA to regulate the emissions of ``motor vehicles'' does 
not encompass trailers. Id. at 1200-03. The Court affirmed, however, 
that both agencies still ``can regulate tractors based on the 
trailers they pull.'' Id. at 1208. Moreover, NHTSA is still 
authorized to regulate trailers in other contexts, such as under 49 
U.S.C. chapter 301. See 49 U.S.C. 30102(a)(7) (defining ``motor 
vehicle'' to include ``a vehicle . . . drawn by mechanical power''); 
Truck Trailer Mfrs. Ass'n, Inc., 17 F.4th at 1207 (``A trailer is 
`drawn by mechanical power.' '').
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    NHTSA, is however, keeping its definition of standard trailer as 
well as other specific types of trailers in 49 CFR 535.4 to assist 
manufacturers in determining tractor performance in the Greenhouse Gas 
Emissions Model (GEM). In October 2016, NHTSA and EPA issued its Phase 
2 Heavy-Duty (HD) National Program final rule that increased efficiency 
standards beginning in model year (MY) 2021.\4\ As part of the 2016 
rulemaking, NHTSA and EPA adopted provisions such that tractor 
performance in GEM is determined by assuming the tractor is pulling a 
``standard'' trailer. The specific characteristics of a standard 
trailer are dependent upon the type of tractor. 40 CFR 1037.501(g) 
provides the specific criteria a standard trailer must meet for 
specific types of trailers. In addition to measurement criteria, some 
standard trailers must be of a specific type (e.g., tank trailer, 
flatbed trailer). Therefore, while NHTSA is removing the requirements 
for trailers, NHTSA is keeping its definition of standard trailer as 
well as other specific types of trailers in 49 CFR 535.4 to assist 
manufacturers in determining tractor performance in GEM.
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    \4\ 81 FR 73478, October 25, 2016.
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C. What are the incremental costs and benefits of this action?

    This action is limited in scope and is not intended to include 
amendments that will have significant economic or environmental 
impacts. NHTSA has therefore not estimated the potential costs or 
benefits of this final rule.

II. Medium and Heavy-Duty Fuel Efficiency Program Technical Amendments

A. Overview of the Medium and Heavy-Duty Fuel Efficiency Program

    In September 2011, NHTSA and EPA finalized Phase 1 of the 
Greenhouse Gas Emissions and Fuel Efficiency Standards for Medium- and 
Heavy-Duty Engines and Vehicles.\5\ The Phase 1 program covered new 
commercial heavy-duty vehicles and work trucks manufactured in model 
years 2014 through 2020, with unique standards for combination 
tractors, heavy-duty pickup trucks and vans, and vocational vehicles, 
as well as separate standards for engines in tractors and vocational 
vehicles. NHTSA and EPA finalized Phase 2 of the standards in October 
2016.\6\ In addition to more stringent standards, the Phase 2 program 
also incorporated enhanced test procedures that (among other things) 
allow individual drivetrain and powertrain performance to be reflected 
in the vehicle certification process; and included an expanded and 
improved compliance simulation model.
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    \5\ 76 FR 57106, September 15, 2011.
    \6\ 81 FR 73478, October 25, 2016.
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    Since the promulgation of the Phase 2 regulations, manufacturers 
have been revising their internal test procedures for compliance with 
the new

[[Page 18810]]

requirements that began for model year 2021. While doing so, they have 
made the agencies aware of several areas in which the test procedure 
regulations could be improved (in terms of overall accuracy, 
repeatability, and clarity) without changing the effective stringency 
of the standards.
    In its May 12, 2020 NPRM, EPA proposed numerous changes to the test 
procedure regulations to address manufacturers' concerns in addition to 
other issues it had identified.\7\ EPA sought comment on those changes 
and issued a final rule on June 29, 2021 responding to the comments and 
adjusting the regulatory changes as appropriate.\8\ After carefully 
reviewing all technical amendments in the EPA proposal, public comments 
to EPA's proposal, and the technical amendments that EPA finalized, 
NHTSA published a NPRM proposing technical amendments to its 
regulations that parallel the technical amendments that EPA has 
finalized.\9\ After providing opportunity for public comment, NHTSA is 
now finalizing its proposed technical amendments. NHTSA's regulatory 
changes described below consist primarily of references and definitions 
contained in NHTSA regulations which were impacted by the technical 
amendments finalized by the EPA. This final rule also includes various 
minor editorial changes to NHTSA's regulations that simply correct 
typographical/formatting errors or revise NHTSA's regulatory text to 
improve clarity or to update references to EPA regulations that have 
changed as a result of the EPA technical amendments.
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    \7\ 85 FR 28140.
    \8\ 86 FR 34308, as corrected by documents published on 
September 23, 2021 (86 FR 52833) and October 26, 2022 (87 FR 64864).
    \9\ 87 FR 56156, September 13, 2022.
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B. Public Participation Opportunities and Summary of Comments

    NHTSA published the NPRM on September 13, 2022, and provided a 60-
day comment period. The agency left the docket open with the intention 
to consider late comments to the extent practicable. NHTSA's docket 
received two comments from individual members of the public 
10 11 and one comment from a stakeholder organization,\12\ 
for an overall total of three comment submissions. The two comments 
from members of the public were outside the scope of the proposal.
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    \10\ Docket ID: NHTSA-2020-0079-0002 commenter recommended stop 
engine testing and allowing unrestricted engines to be produced for 
all diesel vehicles.
    \11\ Docket ID: NHTSA-2020-0079-0004 commenter recommended 
including ``off-road'' vehicles in these regulations and reduce the 
emissions of on-road vehicles.
    \12\ Docket ID: NHTSA-2020-0079-003 Allison Transmission 
commented on the current version of the Greenhouse Gas Emissions 
Model and recommended five future changes to it.
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    The stakeholder organization, Allison Transmission (Allison), 
commented on the current version of the Greenhouse Gas Emissions Model 
(GEM). Allison commented that ``while the current version of GEM offers 
adequate modeling of emissions in vehicles, Allison believes that some 
future changes to GEM could prove to be beneficial in improving the 
overall accuracy of the model.'' Allison then recommended five changes 
to GEM that it believes ``would promote further adoption of current 
vehicle technologies and strategies that improve fuel economy (FE) . . 
. as well as continue to enhance the accuracy of the modeled vs actual 
FE performance.''
    NHTSA appreciates the comment from Allison. However, changes to the 
GEM are beyond the scope of this rulemaking. Although NHTSA relies on 
outputs from GEM to generate emissions and fuel consumption performance 
results and allows manufacturers to use GEM for compliance purposes, 
GEM was developed by EPA, who continues to maintain and update it. 
Accordingly, while NHTSA provides input to EPA regarding GEM and 
conducts its own analysis when deciding the appropriateness of using 
GEM in its fuel efficiency program, comments requesting changes to GEM 
are more appropriately addressed to EPA.
    In conjunction with its final rule issued on June 29, 2021, EPA 
issued a notice of proposed rulemaking (NPRM) proposing further 
revisions to GEM.\13\ In the NPRM, EPA proposed to revise GEM after 
consideration of comments solicited and received on its technical 
amendments NPRM. EPA issued a final rule on July 28, 2022 (87 FR 45257) 
that included corrections, clarifications, additional flexibilities, 
and adjustment factors to improve the GEM compliance tool.\14\
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    \13\ 86 FR 34189.
    \14\ Additional information can be found on EPA's website. 
``Greenhouse Gas Emissions Model (GEM) for Medium- and Heavy-Duty 
Vehicle Compliance.'' (n.d.). https://www.epa.gov/regulations-emissions-vehicles-and-engines/greenhouse-gas-emissions-model-gem-medium-and-heavy-duty. Accessed July 2, 2023.
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    While none of the comments NHTSA received were within the scope of 
the proposal, the agency appreciates the information and opinions 
provided.

C. Overview of the Final Rule

    NHTSA is largely finalizing the requirements proposed in the NPRM. 
Although NHTSA is not making any changes based on the comments 
received, NHTSA is making minor changes to better align NHTSA with the 
changes EPA finalized regarding updates to the GEM as well as other 
minor technical amendments. The changes NHTSA is finalizing are 
described in more detail below.

D. Authority Citation for Part 535

    NHTSA is amending the citation for part 535 to remove reference to 
49 U.S.C. 30101 because the provision does not pertain to NHTSA's 
authority to establish a fuel efficiency program for medium- and heavy-
duty vehicles and engines.

E. 49 CFR 535.1 Scope

    NHTSA is amending Sec.  535.1 by removing the reference to trailers 
from the scope section of MDHD Fuel Efficiency Program regulation, 
consistent with the 2021 D.C. Circuit decision discussed above.

F. 49 CFR 535.3 Applicability

1. Section 535.3(a) Enforcement Action Related to Compliance With NHTSA 
Standards
    While NHTSA proposed amending Sec.  535.3(a) to clarify the 
applicability and compliance provisions of its MDHD Fuel Efficiency 
Program, NHTSA no longer believes the proposed changes are appropriate. 
Accordingly, NHTSA is not finalizing any changes to Sec.  535.3(a).
2. Section 535.3(c) Applicable Vehicle and Engine Manufacturers
    NHTSA is revising Sec.  535.3(c) by removing an outdated reference 
to 40 CFR part 86 and adding the specific subpart references for 40 CFR 
parts 1036 and 1037, such that the regulation will now reference 40 CFR 
part 1036, subpart C and 40 CFR part 1037, subpart C.
3. Section 535.3(d)(5) Exclusion of Heavy-Duty Trailers
    NHTSA is removing paragraph (d)(5) from Sec.  535.3, consistent 
with the 2021 D.C. Circuit decision discussed above, and reserving it 
for future use.
4. Section 535.3(e)(1) Off-Road Vocational Vehicle Exemption
    NHTSA is revising Sec.  535.3(e)(1) by removing details regarding 
exemptions and just referencing NHTSA's provision at Sec.  535.5(b)(9) 
that provides complete details about off-road exemptions. This change 
is intended to reduce confusion by providing details in only one 
location in NHTSA's regulations. Although NHTSA proposed adding 
additional details to paragraph (e)(1) to

[[Page 18811]]

better align with EPA's provision, NHTSA now believes those details 
would be more appropriately placed in Sec.  535.5(b)(9). As discussed 
below, NHTSA is finalizing a technical amendment to add language to 
Sec.  535.5(b)(9) that allows vocational vehicles with a date of 
manufacture before January 1, 2021, to automatically qualify for an 
exemption under Sec.  535.5(b)(9) if the tires installed on the vehicle 
have a maximum speed rating at or below 55 miles per hour. This new 
provision, found at 49 CFR 535.5(b)(9)(i), reflects the intention of 
the NPRM and achieves consistency with 40 CFR 1037.150(h).
5. Section 535.3(e)(2)(ii)(A) and (B) Early Certification for Small 
Manufacturers
    In the NPRM, NHTSA proposed adding paragraphs (A) and (B) to Sec.  
535.3(e)(2)(ii) to discuss two flexibilities to NHTSA's compliance 
provisions for small manufacturers. While, NHTSA is not finalizing the 
exact language proposed, NHTSA is finalizing the substance of the 
proposed change. Vehicle manufacturers that qualify as small businesses 
are exempt from the Phase 1 standards but must meet the Phase 2 
standards beginning January 1, 2022. However, some vehicle families 
have been certified voluntarily to Phase 1 standards by small 
manufacturers. To encourage more voluntary early certification to Phase 
1 standards, EPA finalized a new interim provision in 40 CFR 
1037.150(c)(4) for small manufacturers that certify their entire U.S.-
directed production volume to the Phase 1 standards for calendar year 
2021 (see 86 FR 34337). These small manufacturers will be allowed to 
certify to the Phase 1 standards for model year 2022, instead of the 
otherwise applicable Phase 2 standards. The agencies believe that early 
compliance with the Phase 1 standards should more than offset any 
reduction in benefits that will otherwise be achieved from meeting 
Phase 2 standards starting January 1, 2022.\15\ NHTSA is finalizing 
this change at Sec.  535.3(e)(2)(ii)(B) and has shifted some existing 
language from Sec.  535.3(e)(2)(ii) into a new subparagraph (A).
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    \15\ EPA stated that it believed that the magnitude of any 
impact on air quality would be small because of the low production 
volumes from these small business manufacturers.
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    NHTSA also proposed allowing Phase 1 compliance credits that small 
manufacturers generate from model years 2018 through 2022 for 
vocational vehicles to be used through model year 2027. In the NPRM, 
NHTSA cited EPA's rationale for making its corresponding change. In its 
final rule, EPA stated that the agencies believe that the limit on 
credit life can be problematic for small manufacturers because their 
limited product lines provide them with less flexibility when averaging 
their fleets. EPA also stated that the agencies believe the longer 
credit life will provide small manufacturers with additional 
flexibility to ensure all their products are fully compliant by the 
time the Phase 2 standards are fully phased-in for model year 2027. 
NHTSA continues to believe that the rationale for these changes is 
valid. However, the scope of the change is smaller than NHTSA 
recognized when proposing the additional flexibility for small 
manufacturers. NHTSA's rationale in adopting EPA's reasoning was 
predicated on an incorrect understanding of the regulation. In 
proposing the technical amendment, NHTSA believed that all credit carry 
forwards for vocational vehicles between Phase 1 and Phase 2 were 
limited by the five-year credit life. This is incorrect. Under the 
existing regulations, fuel consumption credits a manufacturer generates 
for light and medium heavy-duty vocational vehicles in model years 2018 
through 2021 may be used through model year 2027, instead of being 
limited to a five-year credit life. These credits, generated under the 
Phase 1 program, can be used for compliance in the Phase 2 averaging, 
banking, and trading program. The existing regulations limit the use of 
fuel consumption credits generated for heavy heavy-duty vocational to a 
five-year credit life. Therefore, the proposed change would only extend 
the credit flexibility to heavy heavy-duty vocational vehicles produced 
by small manufacturers.
    As EPA stated in its final rule, the agencies believe that the 
limit on credit life can be problematic for small manufacturers because 
their limited product lines provide them with less flexibility when 
averaging their fleets. The agencies believe the longer credit life 
will provide small manufacturers with additional flexibility to ensure 
all their products are fully compliant by the time the Phase 2 
standards are fully phased-in for model year 2027. Therefore, NHTSA 
will finalize an amendment, harmonizing with EPA's regulations, to 
allow fuel consumption credits generated for heavy heavy-duty 
vocational vehicles produced by small manufacturers in model years 2018 
through 2021 to be used through 2027, instead of being limited to a 
five-year credit life. This provision, however, is being more 
appropriately added to Sec.  535.7(a)(8), which includes provisions for 
credit transfers between Phase 1 and Phase 2.
    Additionally, NHTSA is finalizing an amendment to address credit 
carry forwards for small manufacturers that certify 2022 vehicles to 
Phase 1 standards if the manufacturer voluntarily certified its entire 
U.S.-directed production volume to the Phase 1 standards for calendar 
year 2021. Specifically, NHTSA is adding a provision stating that fuel 
consumption credits that a small manufacturer generates for vocational 
vehicles in model year 2022 that are certified to Phase 1 standards as 
permitted under Sec.  535.3(e)(2)(ii)(B) may be used through model year 
2027. This provision is also being more appropriately added to Sec.  
535.7(a)(8), which includes provisions for credit transfers between 
Phase 1 and Phase 2. Although NHTSA's rationale for making this change 
varies slightly from EPA, the changes themselves maintain program 
alignment across both agencies.
6. Section 535.3(e)(3) Transitional Allowance for Trailers
    NHTSA is removing 535.3(e)(3) from its regulations, consistent with 
the 2021 D.C. Circuit decision discussed above, and reserving it for 
future use.
Section 535.3(j) Potential Enforcement Actions for Incomplete, 
Incorrect or Fraudulent Information
    In the NPRM, NHTSA proposed adding paragraph (j) to Sec.  535.3. 
The new paragraph was intended outline eligibility determinations and 
potential enforcement actions under the NHTSA fuel efficiency program 
if EPA denies, suspends or revokes, a manufacturer's certificate of 
conformity in accordance with 40 CFR 1036.255 or 1037.255, due to 
incomplete, incorrect or fraudulent information. However, NHTSA has 
decided not to finalize the provision because the agency no longer 
believes it is necessary. Manufacturers that submit fraudulent 
information may be subject to enforcement action under 18 U.S.C. 1001. 
Additionally, there is already an existing provision at Sec.  
535.8(a)(3) explaining that manufacturers providing incomplete 
information may be subject to civil penalties in accordance with 49 
U.S.C. 32912 and a provision at Sec.  535.9(a)(10) indicating actions 
NHTSA may take if EPA suspends or revokes a certificate of conformity.

G. 49 CFR 535.4 Definitions

    NHTSA is adding several new terms to its list of definitions and 
modifying the definitions of several existing terms

[[Page 18812]]

on the list to clarify the meaning of those terms. Almost all these 
definitions reference EPA regulatory definitions to ensure alignment of 
the NHTSA and EPA programs.

1. Introductory Text

    NHTSA is amending the introductory text by updating the statutory 
reference for the definitions of the terms manufacture and manufacturer 
to reference 49 U.S.C. 32901.

2. Act

    NHTSA is removing the term Act because it is no longer used in part 
535.
3. Adjustable Parameter
    NHTSA is adding the term adjustable parameter and defining it as 
having the same meaning given in 40 CFR 1065.1001. However, while the 
NPRM proposed only referencing 40 CFR 1037.801, NHTSA now believes it 
is more appropriate to provide the entire definition and reference 40 
CFR 1065.1001, which includes EPA's definition for adjustable 
parameter, and 40 CFR 1068.50, which provides general provisions that 
apply to adjustable parameters.
4. Advanced Technology
    NHTSA is amending the definition of advanced technology to remove 
an outdated reference and to streamline the definition to specify that 
it is specific vehicle technology for which manufacturers may earn 
special credits under Sec.  535.6 and Sec.  535.7 (e.g., hybrids with 
powertrain designs that include energy storage systems, vehicles with 
waste heat recovery, electric vehicles, and fuel cell vehicles).
5. Alterers
    NHTSA is amending the term alterers to be alterer as the definition 
refers to a single manufacturer.
6. Alternative Fuel Conversion
    Although NHTSA proposed adding the term alternative fuel conversion 
and defining it as having the meaning given for clean alternative fuel 
conversion in 40 CFR 85.502, the term already appears in the current 
regulation. Accordingly, NHTSA is not making any changes to the term.
7. Averaging Set
    NHTSA is removing the terms ``Long trailers'' and ``Short 
trailers'' from the definition of Averaging set, consistent with the 
2021 D.C. Circuit decision.
8. Certificate of Conformity
    In its 2021 final rule, EPA amended 40 CFR 1036.225(e) and 
1037.225(e) by adding a statement that clarifies the application date 
for amended applications for the certification of engine and vehicle 
families submitted to EPA under 40 CFR 1036 subpart C and 1037 subpart 
C, respectively.\16\ In response, NHTSA proposed updating its 
definition of Certificate of Conformity to include the same language 
finalized by EPA because the clarifications are also applicable to 
NHTSA's fuel efficiency program. After further consideration, NHTSA 
determined that no changes were needed to NHTSA's current definition to 
maintain program alignment across the agencies. Accordingly, NHTSA is 
not finalizing any change to the definition of Certificate of 
Conformity.
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    \16\ 86 FR 34308, as corrected by documents published on 
September 23, 2021 (86 FR 52833) and October 26, 2022 (87 FR 64864).
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9. Certified Emission Level
    NHTSA is finalizing a technical amendment to remove the definition 
of certified emission level because the term is not used within part 
535 and to the extent that term is used in EPA's program for engine and 
vehicle families, the terms are defined in the respective regulations 
at 40 CFR 1036.801 and 1037.801.
10. Class
    NHTSA is removing the reference to trailers from its definition of 
class, consistent with the 2021 D.C. Circuit decision.
11. Defeat Device
    NHTSA is adding the term defeat device and defining it as having 
the same meaning given in 40 CFR 86.004-2. The addition will include a 
full definition of the term and note that the term is also defined in 
EPA's regulations at 40 CFR 86.004-2.
12. Emission Data Engine
    Although NHTSA proposed adding the term emission data engine and 
defining it as having the meaning given in 40 CFR 1036.801, NHTSA has 
reconsidered. Since the term is not used in part 535, NHTSA does not 
believe it is necessary or appropriate to define the term at Sec.  
535.4.
13. Engine Configuration
    NHTSA is adding the term engine configuration and defining it as 
having the same definition as given in 40 CFR 1036.801. However, while 
the NPRM proposed only referencing 40 CFR 1036.801, NHTSA now believes 
it is more appropriate to provide the entire definition and noting that 
the definition is also found in 40 CFR 1036.801.
14. Engine Identification Number
    NHTSA is adding the term engine identification number and defining 
it to have the same meaning as given in 40 CFR 1036.801 for 
identification number. This nonsubstantive change is to maintain 
alignment with EPA's program.
15. Flexible-Fuel
    NHTSA is adding the term flexible-fuel and defining it as having 
the same meaning given in 40 CFR 1036.801. However, while the NPRM 
proposed only referencing 40 CFR 1036.801, NHTSA now believes it is 
more appropriate to provide the entire definition and noting that the 
definition is also found in 40 CFR 1036.801.
16. Fuel Type
    NHTSA is adding the term fuel type and defining it as having the 
same meaning given in 40 CFR 1036.801. However, while the NPRM proposed 
only referencing 40 CFR 1036.801, NHTSA now believes it is more 
appropriate to provide the entire definition and noting that the 
definition is also found in 40 CFR 1036.801.
17. Gear Ratio
    NHTSA is adding the term gear ratio or transmission gear ratio, kg 
and defining it as having the same meaning given in 40 CFR 1037.801. 
However, while the NPRM proposed referencing 40 CFR 1036.801, the 
correct reference is Sec.  1037.801. Additionally, while NHTSA proposed 
only referencing EPA's definition, NHTSA now believes it is more 
appropriate to provide the entire definition and noting that the 
definition is also found in 40 CFR 1037.801.
18. Good Engineering Judgment
    NHTSA is amending 535.4 to place the term good engineering 
judgement in the correct alphabetical order.
19. Greenhouse Gas
    In the NPRM, NHTSA proposed adding the term greenhouse gas and 
defining it as having the meaning given in 40 CFR 1036.801. However, 
upon reconsideration NHTSA has determined that it is unnecessary to 
define it in part 535.

20. Heavy-Duty Engine
    NHTSA is adding the term heavy-duty engine and defining it as 
having the meaning given in 49 CFR 523.2. Although NPRM proposed 
referencing both 40 CFR 1036.801 and 49 CFR 523.2, NHTSA believes it is 
unnecessary to reference both. Additionally, NHTSA

[[Page 18813]]

will reference the specific section, Sec.  523.2, instead of the 
general part number.
21. Hybrid or Hybrid Vehicle
    NHTSA is amending the term hybrid vehicle to be hybrid or hybrid 
vehicle because part 535 uses hybrid as a standalone term to mean 
hybrid vehicle. The definition of hybrid or hybrid vehicle will remain 
the same as the definition of hybrid vehicle currently in Sec.  535.4. 
NHTSA has determined that is not appropriate to reference the 
definition of hybrid in 40 CFR 1036.801 because that term is defined in 
part as an ``engine or powertrain'' and NHTSA's use of the term hybrid 
as a standalone term in part 535 is to hybrid vehicles, not hybrid 
engines or powertrains. This definition aligns with the definition for 
hybrid vehicle in 40 CFR 1037.801.
22. Hybrid Engine
    To develop consistency with the revised hybrid powertrain test 
procedures it recently finalized in 40 CFR part 1036, subpart F, EPA 
has added the term hybrid engine along with its definition to 40 CFR 
1036.801. To maintain alignment across the agencies, NHTSA is removing 
the term hybrid engine or powertrain and adding the terms hybrid engine 
and hybrid powertrain and defining the terms as having the same 
meanings given in 40 CFR 1036.801. However, while the NPRM proposed 
only referencing 40 CFR 1036.801, NHTSA now believes it is more 
appropriate to provide the entire definition and noting that the 
definition is also found in 40 CFR 1036.801.
23. Hybrid Powertrain
    To develop consistency with the revised hybrid powertrain test 
procedures it recently finalized in 40 CFR part 1036, subpart F, EPA 
has added the term hybrid powertrain along with its definition to 40 
CFR 1036.801. To maintain alignment across the agencies, NHTSA is 
adding the term hybrid powertrain and defining it as having the same 
meaning given in 40 CFR 1036.801. However, while the NPRM proposed only 
referencing 40 CFR 1036.801, NHTSA now believes it is more appropriate 
to provide the entire definition and noting that the definition is also 
found in 40 CFR 1036.801.
24. Manufacturer
    In the NPRM, NHTSA proposed adding the term manufacturer and 
defining it as having the meaning given in 40 CFR 1037.801. However, 
NHTSA is not finalizing this change because the term manufacturer is 
defined in 49 U.S.C. 32901, as stated in the introductory paragraph to 
49 CFR 535.4.
25. Model Year
    NHTSA is revising its definition for model year as it pertains to 
vehicles and engines. NHTSA is also removing the reference to trailers 
from its definition of model year as it applies to vehicles, consistent 
with the 2021 D.C. Circuit decision. NHTSA has included the 
specifications for model year for vehicles and engines into a single 
definition as the same term is used for both vehicles and engines. The 
meanings for the vehicle categories and for engines are retained. 
Additionally, while the NPRM proposed adding details regarding ABT 
reports into the definition of model year, NHTSA has reconsidered. The 
details are already found in 49 CFR 535.8 and NHTSA has concluded that 
it is not appropriate or necessary to include them in the definition 
section.
26. Motor Vehicle
    NHTSA is adding the term motor vehicle and defining it as having 
the meaning given in 49 CFR 523.2. Although the NPRM proposed defining 
the term as having the meaning in 49 U.S.C. 32901, NHTSA has since 
realized that the term does not appear in section 32901.
27. Multi-Purpose
    NHTSA is adding the term multi-purpose and defining it as having 
the same meaning given in 40 CFR 1037.801. However, while the NPRM 
proposed only referencing 40 CFR 1037.801, NHTSA now believes it is 
more appropriate to provide the entire definition and noting that the 
definition is also found in 40 CFR 1037.801.
28. Neutral-Idle
    NHTSA is adding the term neutral-idle and defining it as having the 
same meaning given in 40 CFR 1037.801. However, while the NPRM proposed 
only referencing 40 CFR 1037.801, NHTSA now believes it is more 
appropriate to provide the entire definition and noting that the 
definition is also found in 40 CFR 1037.801.
29. New Vehicles
    In the NPRM, NHTSA proposed adding the term new vehicles and 
defining it as having the meaning given to new motor vehicle in 40 CFR 
1037.801. However, upon reconsideration, NHTSA has determined that is 
not necessary to define the term in part 535.
30. Percent
    NHTSA is adding the term percent and defining it as having the same 
meaning given in 40 CFR 1065.1001, which is the definition referenced 
in 40 CFR 1037.801. However, while the NPRM proposed only referencing 
40 CFR 1037.801, NHTSA believes it is more appropriate to provide the 
entire definition and noting that the definition is also found in 40 
CFR 1037.801 and 40 CFR 1065.1001.
31. Phase 2
    NHTSA is removing the reference to trailers from its definition of 
Phase 2, consistent with the 2021 D.C. Circuit decision.
32. Placed Into Service
    NHTSA is adding the term Placed into service and defining it as 
having the same meaning given in 40 CFR 1037.801. However, while the 
NPRM proposed only referencing 40 CFR 1037.801, NHTSA believes it is 
more appropriate to provide the entire definition and noting that the 
definition is also found in 40 CFR 1037.801.
33. Primary Intended Service Class
    NHTSA is amending the definition of primary intended service class 
to update an incorrect reference in the existing text. The change is 
nonsubstantive and only changes two references in paragraph (2)(iii).
34. Rechargeable Energy Storage System (RESS)
    NHTSA is amending the definition of rechargeable Energy Storage 
System (RESS) to correct a typographical error.
35. Regulatory Subcategory
    NHTSA is removing trailer subcategories from its definition of 
regulatory subcategory, consistent with the 2021 D.C. Circuit decision, 
and reserving the paragraph for future use.
36. Relating To
    NHTSA is adding the term relating to and defining it as having the 
same meaning given in 40 CFR 1037.801. However, while the NPRM proposed 
only referencing 40 CFR 1037.801, NHTSA believes it is more appropriate 
to provide the entire definition and noting that the definition is also 
found in 40 CFR 1037.801.
37. Round
    NHTSA is adding the term round and defining it as having the same 
meaning given in 40 CFR 1065.1001. However, while the NPRM proposed 
only referencing 40 CFR 1065.1001, NHTSA believes it is more 
appropriate to

[[Page 18814]]

provide the entire definition and noting that the definition is also 
found in 40 CFR 1065.1001.
38. Standard Payload
    NHTSA is removing paragraph (3), which includes defined standard 
payloads for trailers, from its definition of standard payload. This 
change is consistent with the 2021 D.C. Circuit decision.
39. Standard Tractor
    In the NPRM, NHTSA proposed amending the definition of standard 
tractor by defining it as having the meaning given in 40 CFR 1037.801 
not 40 CFR 1037.501, which is how it's currently defined. However, upon 
reconsideration, NHTSA determined that it was not necessary to define 
the term in part 535. Accordingly, NHTSA is removing the term standard 
tractor from the definitions section.
40. Standard Trailer
    NHTSA is amending the definition for standard trailer by defining 
it as having the same meaning given in 40 CFR 1037.801 not 40 CFR 
1037.501, which is how it's currently defined. However, while the NPRM 
proposed only referencing 40 CFR 1037.501, NHTSA now believes it is 
more appropriate to provide the entire definition and note that the 
definition is also found in 40 CFR 1037.801.
41. Stop-Start
    NHTSA is adding the term stop-start and defining it to have the 
same meaning as given for stop-start in 40 CFR 1037.801. However, while 
the proposed regulatory text in the NPRM only included a reference to 
40 CFR 1037.801, NHTSA now believes it is more appropriate to include 
the entire definition and note that the definition is also found in 40 
CFR 1037.801.
42. Suspend
    In the NPRM, NHTSA proposed adding the term Suspend and defining it 
as having the meaning given in 40 CFR 1037.801. However, NHTSA has now 
concluded that the proposed definition is neither necessary nor 
appropriate at it applies to NHTSA's use of the term suspend in part 
535. Accordingly, NHTSA is not adding the term to the definition 
section of part 535.
43. Vehicle Identification Number
    In the NPRM, NHTSA proposed adding the term identification number 
and defining it as having the meaning given in 40 CFR 1037.801. 
However, upon reconsideration, NHTSA realized that the term 
identification number is defined in both 40 CFR part 1037 and 40 CFR 
part 1036, with one term applying to vehicles and one applying to 
engines. To reduce confusion, NHTSA is finalizing amendments to add two 
new terms, vehicle identification number and engine identification 
number. Because NHTSA establishes requirements for vehicles to be 
assigned unique vehicle identification numbers, or VINs, NHTSA is 
defining vehicle identification number for purposes of part 535 as 
having the same meaning as VIN in 49 CFR 565.12.
44. Vehicle Service Class
    NHTSA is revising the definition of vehicle service class to align 
with the changes EPA to their definition given in 40 CFR 1037.140. 
Although the NPRM proposed only referencing EPA's definition in 40 CFR 
1037.140, NHTSA has concluded that it is important to maintain the 
entire definition as there are some important terminology differences 
between EPA's definition and NHTSA's that should be retained. However, 
even with these differences, the terms are aligned.
    The recent EPA technical amendments clarify that the classification 
for tractors, where provisions are the same as vocational vehicles, are 
applicable to both hybrid and non-hybrid vehicles. The amendments also 
clarify that Class 8 hybrid and electric vehicles are considered heavy 
heavy-duty ``HHD'' vehicles while all other vehicles are classified by 
GVWR classes.
    EPA explained in its final rule that prior to these revisions, 
manufacturers had expressed concern that the Phase 2 regulations were 
not specific enough regarding how to classify hybrid vocational 
vehicles, because vocational vehicles are generally classified by the 
class of the engines (as opposed to tractors, which are classified 
based on GVW), which was not applicable to electrically driven vehicles 
that have no engine.
    To address these problems, EPA proposed changes to Sec.  
1037.140(g)(1) to clarify that the classification for tractors where 
provisions are the same as vocational vehicles applies for hybrid and 
non-hybrid vehicles, and paragraph (g)(4) to clarify that Class 8 
hybrid and electric vehicles are Heavy HHVs and all other vehicles are 
classified by GVWR classes. The changes we are finalizing maintain 
alignment with EPA's changes.
45. Void
    In the NPRM, NHTSA proposed adding the term void and defining it as 
having the meaning given in 40 CFR 1037.801. However, NHTSA has now 
concluded that the addition of the term is not necessary as the only 
use of the term in part 535 is in reference to an EPA action, and EPA 
provides its own definition for the term.

H. 49 CFR 535.5 Standards

1. Section 535.5(a) Introductory Text
    NHTSA is amending Sec.  535.5(a) introductory text to clarify its 
regulatory standards relating to heavy-duty pickup trucks and vans. 
More specifically, the agency is adding language that ensures that 
manufacturers use the same options for purposes of grouping vehicles 
and/or engines for applying target standards and determining compliance 
for both EPA's and NHTSA's programs. NHTSA is also adding clarifying 
language explaining that engines installed in vehicles that are subject 
to the standards in paragraph (a) are not subject to the standards in 
paragraph (d) of this section and may not optionally comply with 
paragraph (d).
2. Section 535.5(a)(1)
    NHTSA is amending Sec.  535.5(a)(1) to update an outdated cross 
reference, such that the reference to 40 CFR 86.1819 now reads ``40 CFR 
86.1819-14''.
3. Section 535.5(b) Introductory Text
    NHTSA is amending the introductory text of Sec.  535.5(b) to 
clarify its regulatory standards relating to heavy-duty vocational 
vehicles. More specifically, the agency is adding language that ensures 
manufacturers use the same options for purposes of grouping vehicles 
and/or engines for applying standards and determining compliance for 
both EPA's and NHTSA's programs.
4. Section 535.5(b)(1)(iii)(B)
    NHTSA is removing paragraph (B) from Sec.  535.5(b)(1)(iii) and 
reserving it for future use. This change removes the requirement for 
heavy-duty vocational vehicles that meet the requirement in Sec.  
535.5(b)(1)(iii)(A) by being equipped with tire pressure monitoring 
systems to use low pressure warning and malfunction telltales in clear 
view of the driver as specified in S4.3 and S4.4 of 49 CFR 571.138. The 
revision, however, does not remove the requirements in Sec.  
535.5(b)(6)(vi)(C) for motorhomes that comply with Sec.  
535.5(b)(6)(vi)(B) by having a TPMS.
5. Section 535.5(b)(4)
    NHTSA is correcting the Vocational HHD Vehicle Regional compression 
ignition (CI) standards. The current published standard for this 
vehicle class

[[Page 18815]]

is incorrect and does not align with EPA GHG standards for this vehicle 
type. The incorrect values resulted from an incorrect calculation 
during the Phase 2 rulemaking which intended to maintain alignment of 
the NHTSA and EPA standards. The corrected value for this regulatory 
class is 20.1375 gallons per 1000 ton-miles not 20.2358 gallons per 
1000 ton-miles, which is the currently published standard.
6. Section 535.5(b)(9)(i) Introductory Text
    NHTSA is amending the introductory text of Sec.  535.5(b)(9)(i) to 
align with EPA's technical amendments by adding an exemption provision 
for vocational vehicles with a date of manufacture before January 1, 
2021. With this provision, vocational vehicles automatically qualify 
for an exemption under Sec.  535.5(b)(9), if the tires installed on the 
vehicle have a maximum speed rating at or below 55 miles per hour.
7. Section 535.5(c) Introductory Text
    NHTSA is amending the introductory text of Sec.  535.5(c) to 
clarify its regulatory standards relating to truck tractors. More 
specifically, the agency is adding language that ensures manufacturer 
options (in terms of grouping vehicles and/or engines for purposes of 
applying standards and determining compliance) for EPA and NHTSA 
vehicle standards are aligned across both agencies.
8. Section 535.5(c)(5)
    NHTSA is revising its Alternate Fuel Consumption Standards for 
Tractors above 120,000 pounds GCWR for model year 2021 and later. The 
revised standards are directly aligned with the revised GHG standards 
for this class of vehicles proposed and finalized by EPA as part of its 
technical amendment rulemaking.\17\ The revised standards provide 
additional clarity on this vehicle class along with fuel efficiency 
standards that increase in three increments, model years 2021 through 
2023, model years 2024 through 2026, and model years 2027 and later.
---------------------------------------------------------------------------

    \17\ In December 2020, EPA proposed further revisions to the 
Phase 2 GEM Simulation Model in the December 2020 Notice of Proposed 
Rulemaking (NRPM) for technical amendments to the GHG Emissions 
Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty 
Vehicles and is soliciting comments on these revisions. S. The 
latest EPA's GEM model is released and can be found https://www.epa.gov/regulations-emissions-vehicles-and-engines/greenhouse-gas-emissions-model-gem-medium-and-heavy-duty which incorporates the 
revisions being considered.'' (last accessed: May 11, 2022)
---------------------------------------------------------------------------

    As described in EPA's final rulemaking action, the agencies 
originally defined these alternate fuel consumption and greenhouse-gas 
standards during the Phase 2 rulemaking, to enable Environment and 
Climate Change Canada (ECCC) to fully harmonize with the U.S.'s HD 
Phase 2 standards.
    In the interim, ECCC has since adopted final standards for these 
120,000- to 140,000-pound GCWR tractors, which differ from the optional 
standards finalized in Phase 2.\18\ Since the purpose of these 
standards was to facilitate certification of vehicles intended for 
Canada, EPA proposed optional standards in 40 CFR 1037.670 that would 
be the same as the final ECCC standards, and did not receive any 
adverse comments regarding that proposal. NHTSA is adopting these 
alternative standards, in gallons per 1,000 ton-miles, for 120,000- to 
140,000-pound GCWR tractors that are equivalent to the EPA and ECCC 
standards. This maintains harmonization across the programs for all 
three agencies.
---------------------------------------------------------------------------

    \18\ Regulations Amending the Heavy-duty Vehicle and Engine 
Greenhouse Gas Emission Regulations and Other Regulations Made Under 
the Canadian Environmental Protection Act, 1999: SOR/2018-98, Canada 
Gazette, Part II, Volume 152, Number 11, May 16, 2018.
---------------------------------------------------------------------------

9. Section 535.5(d) Introductory Text
    NHTSA is clarifying the introductory text of 49 CFR 535.5(d) to 
expand its regulatory provision to optionally accommodate powertrain 
families and subfamilies added by EPA in 40 CFR 1036.108(a), and 
1036.230(d), and 1036.230(f). The EPA provisions allow manufacturers to 
apply CO2 standards to powertrain families and subfamilies. 
They also allow manufacturers to optionally certify powertrains using 
the engine testing provisions in 40 CFR part 1036 instead of part 1037. 
Manufacturers may choose to include electric powertrain and hybrid 
electric powertrain emissions in their engine families or subfamilies 
under 40 CFR part 1036 instead of (or in addition to) the otherwise 
applicable engine fuel maps. Doing so provides the same compliance 
options for manufacturers under the EPA and NHTSA programs. NHTSA is 
finalizing a similar amendment to Sec.  535.6(d).
    NHTSA is also amending the introductory text of Sec.  535.5(d) to 
add language that ensures manufacturer options (in terms of grouping 
engines for purposes of applying standards and determining compliance) 
for EPA and NHTSA standards are aligned across both agencies.
10. Section 535.5(d)(3)
    NHTSA is correcting the Heavy-Duty Engine Fuel Consumption 
Standards for Phase 1 MHD and HHD compression ignition (CI) tractor 
engines. The current published standards for these engine classes are 
incorrect, and do not align with EPA GHG standards for these engine 
types. The incorrect values resulted from an incorrect calculation 
during the Phase 2 rulemaking which intended to maintain alignment of 
the NHTSA and EPA standards. The corrected values for these regulatory 
classes are 4.7839 gallons per 100 hp-hr for MHD CI tractor engines and 
4.5187 gallons per 100 hp-hr for HHD CI tractor engines.
11. Section 535.5(d)(11)(i)(A) and (C)
    NHTSA is correcting the Alternate transition option for Phase 2 
engine standards (i)(A) and (C). The current published standards for 
these engine standards are incorrect, and do not align with current EPA 
GHG standards for these engine types. The incorrect values resulted 
from an incorrect calculation during the Phase 2 rulemaking which 
intended to maintain alignment for the NHTSA and EPA standards. The 
corrected values for these regulatory classes are 5.3241 gallons per 
100 hp-hr for MHD vocational vehicle engines and 5.0098 gallons per 100 
hp-hr for HHD vocational engines.
12. Section 535.5(e)
    NHTSA is removing paragraph (e) from Sec.  535.3, which removes the 
Heavy-duty Trailer standards, consistent with the 2021 D.C. Circuit 
decision, discussed above.

I. 49 CFR 535.6 Measurement and Calculation Procedures

1. Section 535.6(b)(1)
    NHTSA is amending Sec.  535.6(b)(1) by adding a reference to EPA's 
finalized regulation at 40 CFR 1037.150. This added reference will 
provide clear guidance that will be used to determine the proper 
vehicle and vehicle family to select when determining a manufacturer's 
regulatory subcategories for vocational vehicles and tractors. The 
addition also maintains program alignment across the agencies.
2. Section 535.6(b)(4)(ii)
    NHTSA is amending Sec.  535.6(b)(4)(ii) by adding references to 
EPA's finalized regulations at 40 CFR 1037.525, 1037.527, and 1037.528. 
These added references clarify how to determine a high-roof tractor's 
aerodynamic performance. EPA finalized this revision to more clearly 
relate the drag areas to

[[Page 18816]]

the defined effective yaw variable, as recommended by EMA as a comment 
to the EPA proposal.\19\ NHTSA is adopting this same measurement schema 
to keep programs aligned across the agencies. NHTSA is also amending 
Sec.  535.6(b)(4)(ii) to provide manufacturers with an alternate 
compliance approach for determining coefficient of aerodynamic drag 
values in GEM.
---------------------------------------------------------------------------

    \19\ The variables 
CdAeffective-yaw-coastdown and 
CdAeffective-yaw-alt are now 
CdAcoastdown([psi]eff) and 
CdAalt([psi]eff), respectively.
---------------------------------------------------------------------------

3. Section 535.6(b)(5)(i)
    NHTSA is revising Sec.  535.6(b)(5)(i) to change the reference to 
an EPA regulation from 40 CFR 1036.510 to 1036.503. This revision 
aligns the NHTSA regulations to the revised and finalized EPA 
regulations, which also keeps the agencies' programs aligned.
4. Section 535.6(b)(5)(v)(E)(3)
    NHTSA is adding paragraph (3) to Sec.  535.6(b)(5)(v)(E), which 
allows manufacturers to characterize torque converters to determine 
their own torque converter capacity factor instead of using the default 
value provided in GEM. This change aligns with EPA provisions in 40 CFR 
1037.570 and maintains program alignment across both agencies.
5. Section 535.6(b)(5)(v)(E)(4)
    NHTSA is adding paragraph (4) to Sec.  535.6(b)(5)(v)(E), which 
allows vocational vehicles to input a value for neutral coasting in GEM 
as a compliance option for its fuel consumption program. This revision 
aligns the NHTSA regulations with the EPA regulations in 40 CFR 
1037.520 and keep both agencies aligned for program compliance.
6. Section 535.6(d) Introductory Text
    Like Sec.  535.5(d), NHTSA is amending the introductory text of 
Sec.  535.6(d) by adding clarifications to Sec.  535.6(d) to expand its 
regulatory provision to optionally accommodate powertrain families and 
subfamilies added by EPA in 40 CFR 1036.108(a), and 1036.230(d), and 
1036.230(f). The EPA provisions allow manufacturers to apply 
CO2 standards to powertrain families and subfamilies. They 
also allow manufacturers to optionally certify powertrains using the 
engine testing provisions in 40 CFR part 1036 instead of part 1037. 
Manufacturers may choose to include electric powertrain and hybrid 
electric powertrain emissions in their engine families or subfamilies 
under 40 CFR part 1036 instead of (or in addition to) the otherwise 
applicable engine fuel maps. Doing so provides the same compliance 
options for manufacturers under the EPA and NHTSA programs.
7. Section 535.6(d)(1)
    NHTSA is updating paragraph (d)(1) to reference to EPA regulation 
40 CFR 1036.501 for engines in heavy-duty truck tractors and vocational 
vehicles that make up each of the manufacturer's regulatory 
subcategories. This replaces the reference to 40 CFR part 86 and 40 CFR 
1036.235. This change maintains alignment across the NHTSA and EPA 
programs.
8. Section 535.6(d)(2) Introductory Text
    NHTSA is amending the introductory text of paragraph (d)(2) to 
align with the EPA regulation 40 CFR 1036.230(f) by expanding this 
regulatory provision to accommodate powertrains other than engines and 
to also include sub-families.
9. Section 535.6(d)(3) Introductory Text
    NHTSA is amending Sec.  535.6(d)(3) introductory text by replacing 
the existing provision with the prescribed emissions tests required for 
medium HD and heavy HD engines certified as a tractor and other long-
haul engine family as well as those certified as a tractor and 
vocational engine family. In the same paragraph, NHTSA also prescribes 
the emissions test required for all other engines. These amendments are 
being made to align with EPA's technical amendments and to provide 
greater clarity to manufacturers about how compliance must be 
determined for the different types of engines.
10. Section 535.6(d)(3)(ii)
    NHTSA is expanding the provisions of Sec.  535.6(d)(3)(ii) to 
powertrains other than engines and subfamilies in addition to families. 
This change is being made to maintain alignment with EPA's technical 
amendments.
11. Section 535.6(e)
    NHTSA is removing paragraph (e) from Sec.  535.6, which removes 
heavy-duty trailers from its measurement and calculation procedures, 
consistent with the 2021 D.C. Circuit decision.

J. 49 CFR 535.7 Averaging, Banking, and Trading (ABT) Credit Program

1. Section 535.7(a) Introductory Text
    NHTSA is removing the references to trailer manufacturers and 
trailers from the introductory text of Sec.  535.7(a), consistent with 
the 2021 D.C. Circuit decision.
2. Section 535.7(a)(2)(v)
    NHTSA is removing the reference to the application of banked or 
traded credits to trailers from Sec.  535.7(a)(2)(v), consistent with 
the 2021 D.C. Circuit decision.
3. Section 535.7(a)(3)(v)
    NHTSA is removing paragraph (v) from Sec.  535.7(a)(3), consistent 
with the 2021 D.C. Circuit decision, and reserving it for future use.
4. Section 535.7(a)(4) Introductory Text
    NHTSA is amending the introductory text of paragraph (a)(4) to 
remove reference to trailers, consistent with the 2021 D.C. Circuit 
decision.
5. Section 535.7(a)(4)(v)
    NHTSA is removing paragraph (v) from Sec.  535.7(a), consistent 
with the 2021 D.C. Circuit decision, and reserving it for future use.
6. Section 535.7(a)(8)(i)
    As discussed above, NHTSA is finalizing two amendments to provide 
greater flexibility to small manufacturers of vocational vehicles. 
First, NHTSA is finalizing an amendment such that fuel consumption 
credits a small manufacturer generates for heavy heavy-duty vocational 
vehicles in model years 2018 through 2021 may be used through 2027, 
instead of being limited to a five-year credit life (this flexibility 
is already provided for fuel consumption credits any manufacturer 
generates for light and medium heavy-duty vocational vehicles in model 
years 2018 through 2021). Second, as discussed above, NHTSA is 
finalizing an amendment to address credit carry forwards for small 
manufacturers that certify 2022 vehicles to Phase 1 standards if the 
manufacturer voluntarily certified its entire U.S.-directed production 
volume to the Phase 1 standards for calendar year 2021. Specifically, 
NHTSA is adding a provision stating that fuel consumption credits that 
a small manufacturer generates for vocational vehicles in model year 
2022 that are certified to Phase 1 standards as permitted under Sec.  
535.3(e)(2)(ii)(B) may be used through model year 2027.
7. Section 535.7(a)(9)(iv)(B)
    NHTSA is amending Sec.  535.7(a)(9)(iv)(B) by adding clarifying 
details regarding corporate relationship status as it relates to 
production limits for generating credits for drayage tractors under the 
custom chassis allowance. In the NPRM, NHTSA proposed language such 
that the limit would apply with respect to vehicles

[[Page 18817]]

produced by the parent manufacturer and its owned subordinate 
companies. However, to better align with existing regulations, NHTSA is 
finalizing language that specifies that the limit applies with respect 
to vehicles produced by manufactures within a control relationship as 
defined in Sec.  534.3.
8. Section 535.7(a)(11)
    NHTSA is adding paragraph (11) to Sec.  535.7(a), which is a 
provision that prevents manufacturers from generating fuel consumption 
credits more than once for compliance. NHTSA has updated the text that 
was proposed in the NPRM to provide greater clarity and to reduce 
ambiguity.
9. Section 535.7(b)(1)
    NHTSA is amending Sec.  535.7(b)(1) to correct the Total MY Fleet 
FCC equation for HDPUVs.
10. Section 535.7(c)(1) Introductory Text
    NHTSA is amending the introductory text Sec.  535.7(c)(1) to 
correct the Vehicle Family FCC equation for vocational vehicle and 
tractor families and subfamilies.
11. Section 535.7(d)(1) Introductory Text
    NHTSA is amending the introductory text of Sec.  535.7(d)(1) to 
correct the Engine Family FCC equation for heavy-duty engine families 
and subfamilies.
12. Section 535.7(d)(7)
    NHTSA is amending Sec.  535.7(d)(7) by removing the conditions for 
when engine credits generated for compression-ignition engines in model 
year 2020 and earlier can be used in model year 2021 and later and 
adding them to new lower-level paragraphs in this section.
13. Section 535.7(d)(7)(i)
    NHTSA is adding paragraph (i) to Sec.  535.7(d)(7), which states 
that engine credits generated for compression-ignition engines 
certified to the tractor engine standards in Sec.  535.5(d) in model 
year 2020 and earlier can be used in model year 2021 and later. This 
provision was in the existing regulation and is just being moved down 
to a lower-level paragraph.
14. Section 535.7(d)(7)(ii)
    NHTSA is also amending Sec.  535.7(d)(7) by removing the provision 
that manufacturers may otherwise use fuel consumption credits generated 
in one model year for certifying vehicles in a later model year without 
adjustment, even if the consumption standards are different. In its 
place, NHTSA is adding paragraph (ii) to Sec.  535.7(d)(7), stipulating 
that fuel consumption credits generated for compression-ignition 
engines certified to the vocational engine standards in Sec.  535.5(d) 
in MY 2020 and earlier can be used in MY 2021 and later in accordance 
with specific requirements. Specifically, the fuel consumption credits 
may only be used in later years relative to specified family 
certification levels (FCLs), consistent with EPA's regulations.
15. Section 535.7(d)(7)(ii)(A)
    NHTSA is adding paragraph (A) to Sec.  535.7(d)(7)(ii), which is 
the FCL manufacturers should use to calculate credits for compression-
ignition medium HD engines certified to the vocational vehicle 
standards in Sec.  535.5(d) in MY 2020 and earlier and will be used in 
MY 2021 and later.
16. Section 535.7(d)(7)(ii)(B)
    NHTSA is adding paragraph (B) to Sec.  535.7(d)(7)(ii), which is 
the FCL manufacturers should use to calculate credits for compression-
ignition heavy HD engines certified to the vocational vehicle standards 
in Sec.  535.5(d) in MY 2020 and earlier and will be used in MY 2021 
and later.
17. Section 535.7(d)(7)(ii)(C)
    NHTSA is adding paragraph (C) to Sec.  535.7(d)(7)(ii), which is 
the provision that provides instructions on how to use the FCLs in 
paragraphs (A) and (B) of this section to recalculate engine credits 
for compression-ignition engines certified to the vocational vehicle 
standards in Sec.  535.5(d) that have been generated in Phase 1 but 
used in Phase 2 of the program.
18. Section 535.7(e)
    NHTSA is removing paragraph (e) from Sec.  535.7, which removes the 
ABT provisions for trailers, consistent with the 2021 D.C. Circuit 
decision, discussed above, and reserving it for future use.
19. Section 535.7(f)(1)(ii) Introductory Text
    NHTSA is amending Sec.  535.7(f)(1)(ii) to clarify the final model 
year in which manufacturers may use the advanced technology credit 
multipliers to increase the credits they earn for advanced technology 
vehicles in Phase 2. In the Phase 2 final rule for the Heavy-Duty 
National Program, NHTSA and EPA jointly explained that we were adopting 
advanced technology credit multipliers for three types of advanced 
technologies. As described in the final rule, there will be a 
multiplier of 3.5 for advanced technology credits for plug-in hybrid 
vehicles, a multiplier of 4.5 for advanced technology credits for all-
electric vehicles, and a multiplier of 5.5 for advanced technology 
credits for fuel cell vehicles. The agencies stated that their 
intention in adopting these multipliers was to create a meaningful 
incentive to manufacturers considering adopting these technologies in 
their vehicles. The agencies further noted that the adoption rates for 
these advanced technologies in heavy vehicles was essentially non-
existent at the time the final rule was issued and seemed unlikely to 
grow significantly within the next decade without additional 
incentives. Because of their large size, the agencies decided to adopt 
them as an interim program that will continue through model year 2027. 
These changes, however, were not accurately reflected in the regulatory 
changes made by the Phase 2 final rule. NHTSA is now amending the 
introductory text of Sec.  535.7(f)(1)(ii) to clarify that for Phase 2, 
advanced technology credits may be increased by the applicable 
multiplier through model year 2027.
20. Section 535.7(f)(1)(ii)(G)
    NHTSA is adding paragraph (G) to Sec.  535.7(f)(1)(ii) to add a 
provision clarifying that advanced technology credits increased with a 
multiplier in Phase 2 cannot be used across averaging sets. In the 
Phase 2 final rule, the agencies explained that because of the adoption 
of the large multipliers, the agencies were discontinuing the allowance 
to use advanced technology credits across averaging sets. This change 
was not accurately reflected in the regulatory changes made by the 
Phase 2 final rule; therefore, NHTSA is adding the provision as Sec.  
535.7(f)(1)(ii)(G).
21. Section 535.7(f)(2)(v)
    NHTSA is removing paragraph (v) from Sec.  535.7(f)(2), which 
removes the provision that provides manufacturers with the ability to 
apply the off-cycle provisions of Sec.  535.7(f)(2) and 40 CFR 1037.610 
to trailers, consistent with the 2021 D.C. Circuit decision discussed 
above, and reserving it for future use.

K. 49 CFR 535.8 Reporting and Recordkeeping Requirements

1. Section 535.8(a)(6)
    NHTSA is amending Sec.  535.8(a)(6) to correct the mailing address 
for NHTSA to 1200 New Jersey Avenue SE, NVS-200, Office W45-306, 
Washington, DC 20590.

[[Page 18818]]

2. Section 535.8(g)(11)(i)(C)
    Like Sec.  535.6(d)(3)(ii), NHTSA is expanding the provisions of 
Sec.  535.8(g)(11)(i)(C) to broaden the language to provide clarity 
that the provision is referring to ``engine and powertrain families and 
subfamilies'' as opposed to just ``engine families.''
3. Section 535.8(g)(12)
    NHTSA is amending Sec.  535.8(g)(12) by removing all references to 
trailers and trailer manufacturers from its production reporting 
requirements, consistent with the 2021 D.C. Circuit decision, discussed 
above.
4. Section 535.8(i)
    NHTSA is amending Sec.  535.8(i) to include a statement reminding 
manufacturers that providing false, fictitious, or fraudulent 
information may subject them to penalties under 18 U.S.C. 1001.

L. 49 CFR 535.9 Enforcement Approach

1. Section 535.9(a)(1)(i)
    NHTSA is amending Sec.  535.9(a)(1)(i) by adding additional 
language and clarifications that NHTSA may conduct audits or perform 
confirmatory testing on any configuration. Any such testing would be 
performed as specified in EPA's regulations and NHTSA will collaborate 
with EPA regarding any potential issues with testing results.
2. Section 535.9(a)(1)(v)
    NHTSA is adding paragraph (v) to Sec.  535.9(a)(1) to add a 
provision stating that NHTSA may require a manufacturer to perform 
selective enforcement audits with respect to any GEM inputs in its 
application for certification or in the end of the year ABT final 
reports. The provision further specifies that any such selective 
enforcement audit would be required to be conducted in a manner 
consistent with EPA's corresponding provisions for selective 
enforcement audits.

M. Section 535.10 How do manufacturers comply with fuel consumption 
standards?

1. Section 535.10(a)(3)
    NHTSA is removing (a)(3) and reserving it for future use. Although 
the NPRM proposed clarifying that EPA's compliance requirements 40 CFR 
1037.601 and 40 CFR part 1068 apply similarly to NHTSA's fuel 
consumption program, except for the warranty provisions in 40 CFR 
1037.601(a)(5), NHTSA has now concluded that it is not appropriate for 
NHTSA to incorporate by reference EPA's general compliance provisions 
for regulations issued under 40 CFR parts 1037 and 1068. Accordingly, 
NHTSA is removing the provisions at (a)(3) and reserving it for future 
use.
2. Section 535.10(a)(6)
    NHTSA is amending Sec.  535.10(a)(6) by clarifying that vehicles 
required to meet the fuel consumption standards of this part must also 
comply with the same requirements as specified in 40 CFR 1037.115(a) 
and (d). However, while the NPRM proposed only referencing 40 CFR 
1037.115, NHTSA has now concluded that it would be more appropriate to 
place the entirety of the substantive requirements into part 535 and 
note that the requirements are consistent with 40 CFR 1037.115(a) and 
(d).
3. Section 535.10(c)(2)
    NHTSA is amending Sec.  535.10(c)(2) by removing the reference to 
box trailers, consistent with the 2021 D.C. Circuit decision, discussed 
above.
4. Section 535.10(c)(3)
    NHTSA is removing Sec.  535.10(c)(3), consistent with the 2021 D.C. 
Circuit decision discussed above, and reserving it for future use.

III. Statutory Authority and Executive Order Reviews

A. Executive Order 12866, Executive Order 14094, Executive Order 13563, 
and DOT Regulatory Policies and Procedures

    We have considered the potential impact of this proposed rule under 
Executive Order 12866, Executive Order 14094, Executive Order 13563, 
and DOT Order 2100.6A. The Office of Management and Budget (OMB) has 
determined that this rule is not a significant regulatory action and, 
therefore, was not submitted to OMB for review.

B. Paperwork Reduction Act (PRA)

    This action does not impose any new information collection burden 
under the PRA. OMB has previously approved the information collection 
activities contained in the existing regulations and has assigned OMB 
control numbers 2060-0104, 2060-0287, 2060-0338, 2060-0545, 2060-0641. 
This rule clarifies and simplifies procedures without affecting 
information collection requirements.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. In 
making this determination, the impact of concern is any significant 
economic impact on small entities. This action is designed to reduce 
testing burdens, increase compliance flexibility, and make various 
corrections and adjustments to compliance provisions. We therefore 
anticipate no costs and no regulatory burden associated with this rule. 
We further do not believe the benefits of this rule would result in 
significant economic impact to regulated small entities. Accordingly, 
we have concluded that this action will have no significant economic 
impact on regulated small entities.

D. Unfunded Mandates Reform Act (UMRA)

    Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA), 
Public Law 104-4, requires Federal 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 
expenditure by State, local, or Tribal governments, in the aggregate, 
or by the private sector, of more than $100 million annually (adjusted 
for inflation with base year of 1995). Adjusting this amount by the 
implicit gross domestic product price deflator for the year 2010 
results in $136 million (110.993/81.606 = 1.36). This rule will not 
result in a cost of $136 million or more to either State, local, or 
Tribal governments, in the aggregate, or the private sector or uniquely 
affect small governments. Thus, this rule is not subject to the 
requirements of sections 202 of the UMRA.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the States, on the relationship between 
the Federal government and the States, or on the distribution of power 
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have Tribal implications as specified in 
Executive Order 13175. This rule will be implemented at the Federal 
level and affects engine and vehicle manufacturers. Thus, Executive 
Order 13175 does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 because it is 
not

[[Page 18819]]

economically significant as defined in Executive Order 12866, and 
because there are no environmental health or safety risks created by 
this action that could present a disproportionate risk to children.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. We have concluded that this action is 
not likely to have any adverse energy effects because it is designed 
merely to reduce testing burdens, increase compliance flexibility, and 
make various corrections and adjustments to compliance provisions.

I. National Technology Transfer and Advancement Act (NTTAA)

    Under the National Technology Transfer and Advancement Act of 1995 
(NTTAA) (Pub. L. 104-113), all Federal agencies and departments shall 
use technical standards that are 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., material specifications, test methods, sampling procedures, and 
business practices) that are developed or adopted by voluntary 
consensus standards bodies, such as the International Organization for 
Standardization (ISO) and the SAE International (SAE). The NTTAA 
directs agencies to provide Congress, through OMB, explanations when 
the agency decides not to use available and applicable voluntary 
consensus standards. NHTSA searched for but did not find voluntary 
consensus standards directly applicable to the amendments in this final 
rule.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    NHTSA believes this action does not have disproportionately high 
and adverse human health or environmental effects on minority 
populations, low-income populations or indigenous peoples, as specified 
in Executive Order 12898 (59 FR 7629, February 16, 1994). Due to the 
lack of environmental impact, these regulatory changes will not have a 
disproportionate adverse effect on minority populations, low-income 
populations, or indigenous peoples.

List of Subjects in 49 CFR Part 535

    Fuel economy, Reporting and recordkeeping requirements.

Regulatory Text

    For the reasons discussed in the preamble, NHTSA is amending 49 CFR 
part 535 as set forth below:

PART 535--MEDIUM- AND HEAVY-DUTY VEHICLE FUEL EFFICIENCY PROGRAM

0
1. The authority citation for part 535 is revised to read as follows:

    Authority:  49 U.S.C. 32902; delegation of authority at 49 CFR 
1.95.


0
2. Revise Sec.  535.1 to read as follows:


Sec.  535.1  Scope.

    This part establishes fuel consumption standards pursuant to 49 
U.S.C. 32902(k) for work trucks and commercial medium- and heavy-duty 
on-highway vehicles (hereafter referenced as heavy-duty vehicles), and 
engines manufactured for sale in the United States. This part 
establishes a credit program that manufacturers may use to comply with 
standards and requirements for manufacturers to provide reports to the 
National Highway Traffic Safety Administration regarding their efforts 
to reduce the fuel consumption of heavy-duty vehicles and engines.

0
3. Amend Sec.  535.3 by revising paragraph (c), removing and reserving 
paragraph (d)(5), and revising paragraph (e).
    The revisions read as follows:


Sec.  535.3  Applicability.

* * * * *
    (c) Vehicle and engine manufacturers that must comply with this 
part include manufacturers required to have approved certificates of 
conformity from EPA as specified in subparts C in 40 CFR parts 1036 and 
1037.
* * * * *
    (e) The following heavy-duty vehicles and engines are exempted from 
the requirements of this part:
    (1) Off-road vehicles. Vocational vehicles intended for off-road 
use are exempt with or without request, subject to the provisions of 
Sec.  535.5(b)(9).
    (2) Small business manufacturers. (i) For Phase 1, small business 
manufacturers are exempted from the vehicle and engine standards of 
Sec.  535.5 but must comply with the reporting requirements of Sec.  
535.8(g).
    (ii) For Phase 2, fuel consumption standards apply on a delayed 
schedule for manufacturers meeting the small business criteria 
specified in 13 CFR 121.201 and in 40 CFR 86.1819-14(k)(5), 1036.150, 
and 1037.150.
    (A) Qualifying manufacturers of truck tractors, vocational 
vehicles, heavy duty pickups and vans, and engines are not subject to 
the fuel consumption standards for vehicles built before January 1, 
2022, and engines (such as those engines built by small alternative 
fuel engine converters) with a date of manufacturer on or after 
November 14, 2011, and before January 1, 2022. Qualifying manufacturers 
may choose to voluntarily comply early.
    (B) Small manufacturers that certify their entire U.S.-directed 
production volume to the Phase 1 standards for calendar year 2021 may 
certify to the Phase 1 standards for model year 2022 (instead of the 
otherwise applicable Phase 2 standards).
    (iii) Small business manufacturers producing vehicles and engines 
that run on any fuel other than gasoline, E85, or diesel fuel meeting 
the criteria specified in 13 CFR 121.201 and in 40 CFR 86.1819-
14(k)(5), 1036.150, and 1037.150 may delay complying with every new 
mandatory standard under this part by one model year.
    (3) [Reserved]
    (4) Engines for specialty vehicles. Engines certified to the 
alternative standards specified in 40 CFR 86.007-11 and 86.008-10 for 
use in specialty vehicles as described in 40 CFR 1037.605. Compliance 
with the vehicle provisions in 40 CFR 1037.605 satisfies compliance for 
NHTSA under this part.
* * * * *

0
4. Revise Sec.  535.4 to read as follows:


Sec.  535.4  Definitions.

    The terms manufacture, manufacturer, commercial medium and heavy-
duty on-highway vehicle, fuel, and work truck are used as defined in 49 
U.S.C. 32901. See 49 CFR 523.2 for general definitions related to 
NHTSA's fuel efficiency programs.
    Adjustable parameter means any device, system, or element of design 
that someone can adjust (including those which are difficult to access) 
and that, if adjusted, may affect measured or modeled emissions (as 
applicable). In some cases, this may exclude a parameter that is 
difficult to access if it cannot be adjusted to affect emissions 
without significantly degrading engine performance, or if it will not 
be adjusted in a way that affects emissions during in-use operation. 
(See 40 CFR 1065.1001 and 40 CFR 1068.50).
    Administrator means the Administrator of the National Highway

[[Page 18820]]

Traffic Safety Administration (NHTSA) or the Administrator's delegate.
    Advanced technology means specific vehicle technology for which 
manufacturers may earn special credits under Sec. Sec.  535.6 and 535.7 
(e.g., hybrids with powertrain designs that include energy storage 
systems, vehicles with waste heat recovery, electric vehicles, and fuel 
cell vehicles).
    Alterer means a manufacturer that modifies an altered vehicle as 
defined in 49 CFR 567.3
    Alternative fuel conversion has the meaning given for clean 
alternative fuel conversion in 40 CFR 85.502
    A to B testing has the meaning given in 40 CFR 1037.801.
    Automated manual transmission has the meaning given in 40 CFR 
1037.801.
    Automatic tire inflation system has the meaning given in 40 CFR 
1037.801.
    Automatic transmission (AT) has the meaning given in 40 CFR 
1037.801.
    Auxiliary power unit has the meaning given in 40 CFR 1037.801.
    Averaging set means, a set of engines or vehicles in which fuel 
consumption credits may be exchanged. Credits generated by one engine 
or vehicle family may only be used by other respective engine or 
vehicle families in the same averaging set as specified in Sec.  535.7. 
Note that an averaging set may comprise more than one regulatory 
subcategory. The averaging sets for this HD program are defined as 
follows:
    (1) Heavy-duty pickup trucks and vans.
    (2) Light heavy-duty (LHD) vehicles.
    (3) Medium heavy-duty (MHD) vehicles.
    (4) Heavy heavy-duty (HHD) vehicles.
    (5) Light heavy-duty engines subject to compression-ignition 
standards.
    (6) Medium heavy-duty engines subject to compression-ignition 
standards.
    (7) Heavy heavy-duty engines subject to compression-ignition 
standards.
    (8) Engines subject to spark-ignition standards.
    (9) Vehicle types certifying to optional custom chassis standards 
as specified in Sec.  535.5(b)(6) form separate averaging sets for each 
vehicle type as specified in Sec.  535.7(c).
    Axle ratio or Drive axle ratio, ka has the meaning given in 40 CFR 
1037.801.
    Basic vehicle frontal area has the meaning given in 40 CFR 
1037.801.
    Cab-complete vehicle has the meaning given in 49 CFR 523.2.
    Carryover has the meaning given in 40 CFR 1037.801.
    Certificate holder means the manufacturer who holds the certificate 
of conformity for the vehicle or engine and that assigns the model year 
based on the date when its manufacturing operations are completed 
relative to its annual model year period.
    Certificate of Conformity means an approval document granted by EPA 
to a manufacturer that submits an application for a vehicle or engine 
emissions family in 40 CFR 1036.205 and 1037.205. A certificate of 
conformity is valid from the indicated effective date until December 31 
of the model year for which it is issued. The certificate must be 
renewed annually for any vehicle a manufacturer continues to produce.
    Certification has the meaning given in 40 CFR 1037.801.
    Chassis-cab means the incomplete part of a vehicle that includes a 
frame, a completed occupant compartment and that requires only the 
addition of cargo-carrying, work-performing, or load- bearing 
components to perform its intended functions.
    Chief Counsel means the NHTSA Chief Counsel, or his or her 
designee.
    Class means relating to GVWR classes for vehicles, as follows:
    (1) Class 2b vehicles are vehicles with a gross vehicle weight 
rating (GVWR) ranging from 8,501 to 10,000 pounds.
    (2) Class 3 through Class 8 vehicles are vehicles with a gross 
vehicle weight rating (GVWR) of 10,001 pounds or more as defined in 49 
CFR 565.15.
    Complete sister vehicle is a complete vehicle of the same 
configuration as a cab-complete vehicle.
    Complete vehicle has the meaning given in 49 CFR part 523.
    Compression-ignition (CI) means relating to a type of 
reciprocating, internal-combustion engine, such as a diesel engine, 
that is not a spark-ignition engine. Note, in accordance with 40 CFR 
1036.1, gas turbine engines and other engines not meeting the 
definition of compression-ignition are deemed to be compression-
ignition engines for complying with fuel consumption standards.
    Configuration means a subclassification within a test group for 
passenger cars, light trucks and medium-duty passenger vehicles and 
heavy-duty pickup trucks and vans which is based on basic engine, 
engine code, transmission type and gear ratios, and final drive ratio.
    Container chassis trailer has the same meaning as container chassis 
in 40 CFR 1037.801.
    Curb weight has the meaning given in 40 CFR 86.1803.
    Custom chassis vehicle means a vocational vehicle that is a motor 
home, school bus, refuse hauler, concrete mixer, emergency vehicle, 
mixed-use vehicle or other buses that are not school buses or motor 
coaches. These vehicle types are defined in 49 CFR 523.3. A ``mixed-use 
vehicle'' is one that meets at least one of the criteria specified in 
40 CFR 1037.631(a)(1) or at least one of the criteria in 40 CFR 
1037.631(a)(2), but not both.
    Date of manufacture means the date on which the certifying vehicle 
manufacturer completes its manufacturing operations, except as follows:
    (1) Where the certificate holder is an engine manufacturer that 
does not manufacture the complete or incomplete vehicle, the date of 
manufacture of the vehicle is based on the date assembly of the vehicle 
is completed.
    (2) EPA and NHTSA may approve an alternate date of manufacture 
based on the date on which the certifying (or primary) vehicle 
manufacturer completes assembly at the place of main assembly, 
consistent with the provisions of 40 CFR 1037.601 and 49 CFR 567.4.
    (3) A vehicle manufacturer that completes assembly of a vehicle at 
two or more facilities may ask to use as the month and year of 
manufacture, for that vehicle, the month and year in which 
manufacturing is completed at the place of main assembly, consistent 
with provisions of 49 CFR 567.4, as the model year. Note that such 
staged assembly is subject to the provisions of 40 CFR 1068.260(c). 
NHTSA's allowance of this provision is effective when EPA approves the 
manufacturer's certificates of conformity for these vehicles.
    Day cab has the meaning given in 40 CFR 1037.801.
    Defeat device means, consistent with 40 CFR 86.004-2, an auxiliary 
emission control device (AECD) that reduces the effectiveness of the 
emission control system under conditions which may reasonably be 
expected to be encountered in normal vehicle operation and use, unless:
    (1) Such conditions are substantially included in the applicable 
Federal emission test procedure for heavy-duty vehicles and heavy-duty 
engines described in subpart N of this part;
    (2) The need for the AECD is justified in terms of protecting the 
vehicle against damage or accident;
    (3) The AECD does not go beyond the requirements of engine 
starting; or
    (4) The AECD applies only for engines that will be installed in 
emergency vehicles, and the need is justified in terms of preventing 
the engine from losing speed, torque, or power due abnormal conditions 
of the emission control system, or in terms of preventing such abnormal 
conditions from occurring, during operation related to

[[Page 18821]]

emergency response. Examples of such abnormal conditions may include 
excessive exhaust backpressure from an overloaded particulate trap, and 
running out of diesel exhaust fluid for engines that rely on urea-based 
selective catalytic reduction.
    Drayage tractor has the meaning given in 40 CFR 1037.801.
    Dual-clutch transmission (DCT) means a transmission has the meaning 
given in 40 CFR 1037.801.
    Dual-fuel has the meaning given in 40 CFR 1037.801.
    Electric vehicle has the meaning given in 40 CFR 1037.801.
    Emergency vehicle means a vehicle that meets one of the criteria in 
40 CFR 1037.801.
    Engine configuration means a unique combination of engine hardware 
and calibration (related to the emission standards) within an engine 
family, which would include hybrid components for engines certified as 
hybrid engines and hybrid powertrains. Engines within a single engine 
configuration differ only with respect to normal production variability 
or factors unrelated to compliance with emission standards. (See 40 CFR 
1036.801).
    Engine family has the meaning given in 40 CFR 1036.230. 
Manufacturers designate families in accordance with EPA provisions and 
may not choose different families between the NHTSA and EPA programs.
    Engine identification number means a unique specification (for 
example, a model number/serial number combination) that allows someone 
to distinguish a particular engine from other similar engines. (See the 
definition of identification number in 40 CFR 1036.801).
    Excluded means a vehicle or engine manufacturer or component is not 
required to comply with any aspects with the NHTSA fuel consumption 
program.
    Exempted means a vehicle or engine manufacturer or component is not 
required to comply with certain provisions of the NHTSA fuel 
consumption program.
    Family certification level (FCL) has the meaning given in 40 CFR 
1036.801.
    Family emission limit (FEL) has the meaning given in 40 CFR 
1037.801.
    Final drive ratio has the meaning given in 40 CFR 1037.801.
    Final-stage manufacturer has the meaning given in 49 CFR 567.3 and 
includes secondary vehicle manufacturers as defined in 40 CFR 1037.801.
    Flatbed trailer has the meaning given in 40 CFR 1037.801.
    Fleet in this part means all the heavy-duty vehicles or engines 
within each of the regulatory sub- categories that are manufactured by 
a manufacturer in a particular model year and that are subject to fuel 
consumption standards under Sec.  535.5.
    Fleet average fuel consumption is the calculated average fuel 
consumption performance value for a manufacturer's fleet derived from 
the production weighted fuel consumption values of the unique vehicle 
configurations within 'ach vehicle model type that makes up that 
manufacturer's vehicle fleet in a given model year. In this part, the 
fleet average fuel consumption value is determined for each 
manufacturer's fleet of heavy-duty pickup trucks and vans.
    Fleet average fuel consumption standard is the actual average fuel 
consumption standard for a manufacturer's fleet derived from the 
production weighted fuel consumption standards of each unique vehicle 
configuration, based on payload, tow capacity and drive configuration 
(2, 4 or all-wheel drive), of the model types that makes up that 
manufacturer's vehicle fleet in a given model year. In this part, the 
fleet average fuel consumption standard is determined for each 
manufacturer's fleet of heavy-duty pickup trucks and vans.
    Flexible-fuel means relating to an engine designed for operation on 
any mixture of two or more different types of fuels. (See 40 CFR 
1036.801).
    Fuel cell means an electrochemical cell that produces electricity 
via the non-combustion reaction of a consumable fuel, typically 
hydrogen.
    Fuel cell electric vehicle means a motor vehicle propelled solely 
by an electric motor where energy for the motor is supplied by a fuel 
cell.
    Fuel efficiency means the amount of work performed for each gallon 
of fuel consumed.
    Fuel type means a general category of fuels such as diesel fuel, 
gasoline, or natural gas. There can be multiple grades within a single 
fuel type, such as premium gasoline, regular gasoline, or gasoline with 
10 percent ethanol. (See 40 CFR 1037.801).
    Gaseous fuel has the meaning given in 40 CFR 1037.801.
    Gear ratio or Transmission gear ratio, kg, means the dimensionless 
number representing the angular speed of the transmission's input shaft 
divided by the angular speed of the transmission's output shaft when 
the transmission is operating in a specific gear. (See 40 CFR 
1037.801).
    Good engineering judgment has the meaning given in 40 CFR 1068.30. 
See 40 CFR 1068.5 for the administrative process used to evaluate good 
engineering judgement.
    Greenhouse gas Emissions Model (GEM) has the meaning given in 40 
CFR 1037.801.
    Gross axle weight rating (GAWR) has the meaning given in 49 CFR 
571.3.
    Gross combination weight rating (GCWR) has the meaning given in 49 
CFR 571.3.
    Gross vehicle weight rating (GVWR) has the meaning given in 49 CFR 
571.3.
    Heavy-duty engine has the meaning given in 49 CFR part 523.2.
    Heavy-duty off-road vehicle means a heavy-duty vocational vehicle 
or vocational tractor that is intended for off-road use.
    Heavy-duty vehicle has the meaning given in 49 CFR part 523.
    Heavy-haul tractor has the meaning given in 40 CFR 1037.801.
    Heavy heavy-duty (HHD) vehicle has the meaning given in vehicle 
service class.
    Hybrid or Hybrid vehicle means a vehicle that includes energy 
storage features (other than a conventional battery system or 
conventional flywheel) in addition to an internal combustion engine or 
other engine using consumable chemical fuel. Supplemental electrical 
batteries and hydraulic accumulators are examples of hybrid energy 
storage systems. Note that certain provisions in this part treat hybrid 
vehicles that include regenerative braking different than those that do 
not include regenerative braking.
    Hybrid engine means a hybrid system with features for storing and 
recovering energy that are integral to the engine or are otherwise 
upstream of the vehicle's transmission other than a conventional 
battery system or conventional flywheel. Supplemental electrical 
batteries and hydraulic accumulators are examples of hybrid energy 
storage systems. Examples of hybrids that could be considered hybrid 
engines are P0, P1, and P2 hybrids where hybrid features are connected 
to the front end of the engine, at the crankshaft, or connected between 
the clutch and the transmission where the clutch upstream of the hybrid 
feature is in addition to the transmission clutch(s), respectively. 
Note other examples of systems that qualify as hybrid engines are 
systems that recover kinetic energy and use it to power an electric 
heater in the aftertreatment. (See 40 CFR 1036.801).
    Hybrid powertrain means a powertrain that includes energy storage 
features other than a conventional battery system or conventional 
flywheel. Supplemental electrical batteries and hydraulic accumulators 
are examples of hybrid energy storage systems. Note

[[Page 18822]]

other examples of systems that qualify as hybrid powertrains are 
systems that recover kinetic energy and use it to power an electric 
heater in the aftertreatment. (See 40 CFR 1037.801).
    Idle operation has the meaning given in 40 CFR 1037.801.
    Incomplete vehicle has the meaning given in 49 CFR part 523. For 
the purpose of this regulation, a manufacturer may request EPA and 
NHTSA to allow the certification of a vehicle as an incomplete vehicle 
if it manufactures the engine and sells the unassembled chassis 
components, provided it does not produce and sell the body components 
necessary to complete the vehicle.
    Innovative technology means technology certified under Sec.  535.7 
and by EPA under 40 CFR 86.1819-14(d)(13), 1036.610, and 1037.610 in 
the Phase 1 program.
    Intermediate manufacturer has the meaning given in 49 CFR 567.3.
    Light heavy-duty (LHD) vehicle has the meaning given in vehicle 
service class.
    Liquefied petroleum gas (LPG) has the meaning given in 40 CFR 
1036.801.
    Low rolling resistance tire means a tire on a vocational vehicle 
with a tire rolling resistance level (TRRL) of 7.7 kg/metric ton or 
lower, a steer tire on a tractor with a TRRL of 7.7 kg/metric ton or 
lower, or a drive tire on a tractor with a TRRL of 8.1 kg/metric ton or 
lower.
    Manual transmission (MT) has the meaning given in 40 CFR 1037.801.
    Medium heavy-duty (MHD) vehicle has the meaning given in vehicle 
service class.
    Model type has the meaning given in 40 CFR 600.002.
    Model year means one of the following for compliance with this 
part. Note that manufacturers may have other model year designations 
for the same vehicle for compliance with other requirements or for 
other purposes:
    (1) For tractors and vocational vehicles with a date of manufacture 
on or after January 1, 2021, the vehicle's model year is the calendar 
year corresponding to the date of manufacture; however, the vehicle's 
model year may be designated to be the year before the calendar year 
corresponding to the date of manufacture if the engine's model year is 
also from an earlier year. Note that paragraph (2) of this definition 
limits the extent to which vehicle manufacturers may install engines 
built in earlier calendar years. Note that 40 CFR 1037.601(a)(2) limits 
the extent to which vehicle manufacturers may install engines built in 
earlier calendar years.
    (2) For Phase 1 tractors and vocational vehicles with a date of 
manufacture before January 1, 2021, model year means the manufacturer's 
annual new model production period, except as restricted under this 
definition. It must include January 1 of the calendar year for which 
the model year is named, may not begin before January 2 of the previous 
calendar year, and it must end by December 31 of the named calendar 
year. The model year may be set to match the calendar year 
corresponding to the date of manufacture.
    (i) The manufacturer who holds the certificate of conformity for 
the vehicle must assign the model year based on the date when its 
manufacturing operations are completed relative to its annual model 
year period. In unusual circumstances where completion of your assembly 
is delayed, we may allow you to assign a model year one year earlier, 
provided it does not affect which regulatory requirements will apply.
    (ii) Unless a vehicle is being shipped to a secondary manufacturer 
that will hold the certificate of conformity, the model year must be 
assigned prior to introduction of the vehicle into U.S. commerce. The 
certifying manufacturer must re-designate the model year if it does not 
complete its manufacturing operations within the originally identified 
model year. A vehicle introduced into U.S. commerce without a model 
year is deemed to have a model year equal to the calendar year of its 
introduction into U.S. commerce unless the certifying manufacturer 
assigns a later date.
    (3) For engines, model year means the manufacturer's annual new 
model production period, except as restricted under this definition. It 
must include January 1 of the calendar year for which the model year is 
named, may not begin before January 2 of the previous calendar year, 
and it must end by December 31 of the named calendar year. 
Manufacturers may not adjust model years to circumvent or delay 
compliance with emission standards or to avoid the obligation to 
certify annually.
    Motor Vehicle has the meaning given in 49 CFR 523.2.
    Multi-purpose means relating to the Multi-Purpose duty cycle as 
specified in 40 CFR 1037.510. (See 40 CFR 1037.801).
    Natural gas has the meaning given in 40 CFR 1036.801. Vehicles that 
use a pilot-ignited natural gas engine (which uses a small diesel fuel 
ignition system), are still considered natural gas vehicles.
    NHTSA Enforcement means the NHTSA Associate Administrator for 
Enforcement, or his or her designee.
    Neutral coasting has the meaning given in 40 CFR 1037.801.
    Neutral idle means a vehicle technology that automatically puts the 
transmission in neutral when the vehicle is stopped, as described in 40 
CFR 1037.660(a). (See 40 CFR 1037.801).
    Off-cycle technology means technology certified under Sec.  535.7 
and by EPA under 40 CFR 86.1819-14(d)(13), 1036.610, and 1037.610 in 
the Phase 2 program.
    Party means the person alleged to have committed a violation of 
Sec.  535.9, and includes manufacturers of vehicles and manufacturers 
of engines.
    Payload means in this part the resultant of subtracting the curb 
weight from the gross vehicle weight rating.
    Percent (%) means a representation of exactly 0.01. Numbers 
expressed as percentages in this part (such as a tolerance of 2%) have infinite precision, so 2% and 2.000000000% have the same 
meaning. This means that where we specify some percentage of a total 
value, the calculated value has the same number of significant digits 
as the total value. For example, 2% of a span value where the span 
value is 101.3302 is 2.026604. (See 40 CFR 1037.801 and 40 CFR 
1065.1001.
    Petroleum has the meaning given in 40 CFR 1037.801.
    Phase 1 means the joint NHTSA and EPA program established in 2011 
for fuel efficiency standards and greenhouse gas emissions standards 
regulating medium- and heavy-duty engines and vehicles. See Sec.  535.5 
for the specific model years that standards apply to vehicles and 
engines.
    Phase 2 means the joint NHTSA and EPA program established in 2016 
for fuel efficiency standards and greenhouse gas emissions standards 
regulating medium- and heavy-duty vehicles and engines. See Sec.  535.5 
for the specific model years that standards apply to vehicles and 
engines.
    Pickup truck has the meaning given in 49 CFR part 523.
    Placed into service means put into initial use for its intended 
purpose, excluding incidental use by the manufacturer or a dealer. (See 
40 CFR 1037.801).
    Plug-in hybrid electric vehicle (PHEV) means a hybrid electric 
vehicle that has the capability to charge the battery or batteries used 
for vehicle propulsion from an off-vehicle electric source, such that 
the off-vehicle source cannot be connected to the vehicle while the 
vehicle is in motion.

[[Page 18823]]

    Power take-off (PTO) means a secondary engine shaft or other system 
on a vehicle that provides substantial auxiliary power for purposes 
unrelated to vehicle propulsion or normal vehicle accessories such as 
air conditioning, power steering, and basic electrical accessories. A 
typical PTO uses a secondary shaft on the engine to transmit power to a 
hydraulic pump that powers auxiliary equipment such as a boom on a 
bucket truck.
    Powertrain family has the meaning given in 40 CFR 1037.231. 
Manufacturers choosing to perform powertrain testing as specified in 40 
CFR 1037.550, divide product lines into powertrain families that are 
expected to have similar fuel consumptions and CO2 emission 
characteristics throughout the useful life.
    Preliminary approval means approval granted by an authorized EPA 
representative prior to submission of an application for certification, 
consistent with the provisions of 40 CFR 1037.210. For requirements 
involving NHTSA, EPA will ensure decisions are jointly made and will 
convey the decision to the manufacturer.
    Primary intended service class has the same meaning for engines as 
specified in 40 CFR 1036.140. Manufacturers must identify a single 
primary intended service class for each engine family that best 
describes vehicles for which it designs and markets the engine, as 
follows:
    (1) Divide compression-ignition engines into primary intended 
service classes based on the following engine and vehicle 
characteristics:
    (i) Light heavy-duty ``LHD'' engines usually are not designed for 
rebuild and do not have cylinder liners. Vehicle body types in this 
group might include any heavy-duty vehicle built from a light-duty 
truck chassis, van trucks, multi-stop vans, and some straight trucks 
with a single rear axle. Typical applications will include personal 
transportation, light-load commercial delivery, passenger service, 
agriculture, and construction. The GVWR of these vehicles is normally 
below 19,500 pounds.
    (ii) Medium heavy-duty ``MHD'' engines may be designed for rebuild 
and may have cylinder liners. Vehicle body types in this group will 
typically include school buses, straight trucks with single rear axles, 
city tractors, and a variety of special purpose vehicles such as small 
dump trucks, and refuse trucks. Typical applications will include 
commercial short haul and intra-city delivery and pickup. Engines in 
this group are normally used in vehicles whose GVWR ranges from 19,500 
to 33,000 pounds.
    (iii) Heavy heavy-duty ``HHD'' engines are designed for multiple 
rebuilds and have cylinder liners. Vehicles in this group are normally 
tractors, trucks, straight trucks with dual rear axles, and buses used 
in inter-city, long-haul applications. These vehicles normally exceed 
33,000 pounds GVWR.
    (2) Divide spark-ignition engines into primary intended service 
classes as follows:
    (i) Spark-ignition engines that are best characterized by paragraph 
(1)(i) or (ii) of this section are in a separate ``spark-ignition'' 
primary intended service class.
    (ii) Spark-ignition engines that are best characterized by 
paragraph (1)(iii) of this section share a primary intended service 
class with compression-ignition heavy heavy-duty engines. Gasoline-
fueled engines are presumed not to be characterized by paragraph 
(1)(iii) of this section; for example, vehicle manufacturers may 
install some number of gasoline-fueled engines in Class 8 trucks 
without causing the engine manufacturer to consider those to be heavy 
heavy-duty engines.
    (iii) References to ``spark-ignition standards'' in this part 
relate only to the spark-ignition engines identified in paragraph 
(2)(i) of this definition. References to ``compression-ignition 
standards'' in this part relate to compression-ignition engines, to 
spark-ignition engines optionally certified to standards that apply to 
compression-ignition engines, and to all engines identified under 
paragraph (2)(ii) of this definition as heavy heavy-duty engines.
    Rechargeable Energy Storage System (RESS) means the component(s) of 
a hybrid engine or vehicle that store recovered energy for later use, 
such as the battery system in an electric hybrid vehicle.
    Refuse hauler has the meaning given in 40 CFR 1037.801.
    Regional has the meaning relating to the Regional duty cycle as 
specified in 40 CFR 1037.510.
    Regulatory category means each of the four types of heavy-duty 
vehicles defined in 49 CFR 523.6 and the heavy-duty engines used in 
these heavy-duty vehicles.
    Regulatory subcategory means the sub-groups in each regulatory 
category to which mandatory fuel consumption standards and requirements 
apply as specified in 40 CFR 1036.230 and 1037.230 and are defined as 
follows:
    (1) Heavy-duty pick-up trucks and vans.
    (2) Vocational vehicle subcategories have 18 separate vehicle 
service classes as shown in paragraphs (2)(i) and (ii) of this 
definition and include vocational tractors. Paragraph (2)(i) of this 
definition includes vehicles complying with Phase 1 standards. Phase 2 
vehicles are included in paragraph (2)(ii) of this definition which 
have separate subcategories to account for engine characteristics, 
GVWR, and the selection of duty cycle for vocational vehicles as 
specified in 40 CFR 1037.510; vehicles may additionally fall into one 
of the subcategories defined by the custom-chassis standards in Sec.  
535.5(b)(6) and 40 CFR 1037.105(h). Manufacturers using the alternate 
standards in Sec.  535.5(b)(6) and 40 CFR 1037.105(h) should treat each 
vehicle type as a separate vehicle subcategory.
    (i) Phase 1 Vocational Vehicle Subcategories. (A) Vocational LHD 
vehicles.
    (B) Vocational MHD vehicles.
    (C) Vocational HHD vehicles.
    (ii) Phase 2 vocational vehicle subcategories.

----------------------------------------------------------------------------------------------------------------
             Engine type               Vocational LHD vehicles  Vocational MHD vehicles  Vocational HHD vehicles
----------------------------------------------------------------------------------------------------------------
CI...................................  Urban..................  Urban..................  Urban.
CI...................................  Multi-Purpose..........  Multi-Purpose..........  Multi-Purpose.
CI...................................  Regional...............  Regional...............  Regional.
SI...................................  Urban..................  Urban..................  N/A.
SI...................................  Multi-Purpose..........  Multi-Purpose..........  N/A.
SI...................................  Regional...............  Regional...............  N/A.
----------------------------------------------------------------------------------------------------------------

    (3) Tractor subcategories are shown in paragraph (3)(i) of this 
definition for Phase 1 and 2. Paragraph (3)(i) includes 10 separate 
subcategories for tractors complying with Phase 1 and 2 standards. The 
heavy-haul tractor subcategory only applies for Phase 2.

[[Page 18824]]

    (i) Phase 1 and 2 truck tractor subcategories.

------------------------------------------------------------------------
                                                        Class 8 sleeper
             Class 7               Class 8 day cabs          cabs
------------------------------------------------------------------------
Low-roof tractors...............  Low-roof day cab    Low-roof sleeper
                                   tractors.           cab tractors.
Mid-roof tractors...............  Mid-roof day cab    Mid-roof sleeper
                                   tractors.           cab tractors.
High-roof tractors..............  High-roof day cab   High-roof sleeper
                                   Tractors.           cab tractors.
                                 ---------------------------------------
N/A.............................   Heavy-haul tractors (applies only to
                                             Phase 2 program).
------------------------------------------------------------------------

    (ii) [Reserved]
    (4) [Reserved]
    (5) Engine subcategories are shown for each primary intended 
service class in paragraph (5)(i) of this definition. Paragraph (5)(i) 
includes 6 separate subcategories for engines which are the same for 
Phase 1 and 2 standards.
    (i) Engine subcategories.

------------------------------------------------------------------------
           LHD engines                MHD engines         HHD engines
------------------------------------------------------------------------
CI engines for vocational         CI engines for      CI engines for
 vehicles.                         vocational          vocational
                                   vehicles.           vehicles.
N/A.............................  CI engines for      CI engines for
                                   truck Tractors.     truck tractors.
-----------------------------------------------------
All spark-ignition engines..........................  N/A.
------------------------------------------------------------------------

    (ii) [Reserved]
    Relating to as used in this section means relating to something in 
a specific, direct manner. This expression is used in this section only 
to define terms as adjectives and not to broaden the meaning of the 
terms. (See 40 CFR 1037.801).
    Revoke has the same meaning given in 40 CFR 1068.30.
    Roof height means the maximum height of a vehicle (rounded to the 
nearest inch), excluding narrow accessories such as exhaust pipes and 
antennas, but including any wide accessories such as roof fairings. 
Measure roof height of the vehicle configured to have its maximum 
height that will occur during actual use, with properly inflated tires 
and no driver, passengers, or cargo onboard. Determine the base roof 
height on fully inflated tires having a static loaded radius equal to 
the arithmetic mean of the largest and smallest static loaded radius of 
tires a manufacturer offers or a standard tire EPA approves. If a 
vehicle is equipped with an adjustable roof fairing, measure the roof 
height with the fairing in its lowest setting. Once the maximum height 
is determined, roof heights are divided into the following categories:
    (1) Low-roof means a vehicle with a roof height of 120 inches or 
less.
    (2) Mid-roof means a vehicle with a roof height between 121 and 147 
inches.
    (3) High-roof means a vehicle with a roof height of 148 inches or 
more.
    Round means to apply the rounding convention specified in 40 CFR 
1065.20(e), unless otherwise specified. (See 40 CFR 1065.1001).
    Secondary vehicle manufacturer has the same meaning as final-stage 
manufacturer in 49 CFR part 567.
    Service class group means a group of engine and vehicle averaging 
sets defined as follows:
    (1) Spark-ignition engines, light heavy-duty compression-ignition 
engines, light heavy-duty vocational vehicles and heavy-duty pickup 
trucks and vans.
    (2) Medium heavy-duty compression-ignition engines and medium 
heavy-duty vocational vehicles and tractors.
    (3) Heavy heavy-duty compression-ignition engines and heavy heavy-
duty vocational vehicles and tractors.
    Sleeper cab means a type of truck cab that has a compartment behind 
the driver's seat intended to be used by the driver for sleeping. This 
includes both cabs accessible from the driver's compartment and those 
accessible from outside the vehicle.
    Small business manufacturer means a manufacturer meeting the 
criteria specified in 13 CFR 121.201. For manufacturers owned by a 
parent company, the employee and revenue limits apply to the total 
number employees and total revenue of the parent company and all its 
subsidiaries.
    Spark-ignition (SI) means relating to a gasoline-fueled engine or 
any other type of engine with a spark plug (or other sparking device) 
and with operating characteristics significantly similar to the 
theoretical Otto combustion cycle. Spark-ignition engines usually use a 
throttle to regulate intake air flow to control power during normal 
operation. Note that some spark-ignition engines are subject to 
requirements that apply for compression-ignition engines as described 
in 40 CFR 1036.140.
    Standard payload means the payload assumed for each vehicle, in 
tons, for modeling and calculating emission credits, as follows:
    (1) For vocational vehicles:
    (i) 2.85 tons for light heavy-duty vehicles.
    (ii) 5.6 tons for medium heavy-duty vehicles.
    (iii) 7.5 tons for heavy heavy-duty vocational vehicles.
    (2) For tractors:
    (i) 12.5 tons for Class 7.
    (ii) 19 tons for Class 8.
    (iii) 43 tons for heavy-haul tractors.
    Standard trailer means a trailer that meets the applicable criteria 
found in 40 CFR 1037.501(g). (See 40 CFR 1037.801).
    Stop-start means a vehicle technology that automatically turns the 
engine off when the vehicle is stopped, as described in 40 CFR 
1037.660(a). (See the definition for stop-start in 40 CFR 1037.801)
    Subconfiguration means a unique combination within a vehicle 
configuration of equivalent test weight, road-load horsepower, and any 
other operational characteristics or parameters that EPA determines may 
significantly affect CO2 emissions within a vehicle 
configuration as defined in 40 CFR 600.002.
    Tank trailer has the meaning given in 40 CFR 1037.801.
    Test group means the multiple vehicle lines and model types that 
share critical emissions and fuel consumption related features and that 
are certified as a group by a common certificate of conformity issued 
by EPA and is used collectively with other test groups within an 
averaging set or regulatory subcategory and is used by NHTSA for 
determining the fleet average fuel consumption.

[[Page 18825]]

    The agencies means the National Highway Traffic Safety 
Administration (NHTSA) and the Environmental Protection Agency (EPA) in 
this part.
    Tire pressure monitoring system (TPMS) has the meaning given in 
section S3 of 49 CFR 571.138.
    Tire rolling resistance level (TRRL) means a value with units of 
kg/metric ton that represents that rolling resistance of a tire 
configuration. TRRLs are used as inputs to the GEM model under 40 CFR 
1037.520. Note that a manufacturer may assign a value higher than a 
measured rolling resistance of a tire configuration.
    Towing capacity in this part is equal to the resultant of 
subtracting the gross vehicle weight rating from the gross combined 
weight rating.
    Trade means to exchange fuel consumption credits, either as a buyer 
or a seller.
    U.S.-directed production volume means the number of vehicle units, 
subject to the requirements of this part, produced by a manufacturer 
for which the manufacturer has a reasonable assurance that sale was or 
will be made to ultimate purchasers in the United States.
    Useful life has the meaning given in 40 CFR 1036.801 and 1037.801.
    Vehicle configuration means a unique combination of vehicle 
hardware and calibration (related to measured or modeled emissions) 
within a vehicle family as specified in 40 CFR 1037.801. Vehicles with 
hardware or software differences, but that have no hardware or software 
differences related to measured or modeled emissions or fuel 
consumption can be included in the same vehicle configuration. Note 
that vehicles with hardware or software differences related to measured 
or modeled emissions or fuel consumption are considered to be different 
configurations even if they have the same GEM inputs and FEL. Vehicles 
within a vehicle configuration differ only with respect to normal 
production variability or factors unrelated to measured or modeled 
emissions and fuel consumption for EPA and NHTSA.
    Vehicle family has the meaning given in 40 CFR 1037.230. 
Manufacturers designate families in accordance with EPA provisions and 
may not choose different families between the NHTSA and EPA programs. 
If a manufacturer is certifying vehicles within a vehicle family to 
more than one FEL, it must subdivide its greenhouse gas and fuel 
consumption vehicle families into subfamilies that include vehicles 
with identical FELs. Note that a manufacturer may add subfamilies at 
any time during the model year.
    Vehicle identification number has the meaning given in 49 CFR 
565.12 for VIN.
    Vehicle service class means classes of vehicles, generally based on 
a vehicle's weight class, that are used for purposes of determining 
applicable requirements. The vehicle service classes defined here for 
use in this part align with the vehicle service classes specified in 40 
CFR 1037.140(g). Fuel consumption standards and other provisions of 
this part apply to specific vehicle service classes for tractors and 
vocational vehicles as follows:
    (1) Phase 1 and Phase 2 tractors are divided based on GVWR into 
Class 7 tractors and Class 8 tractors. Where provisions apply to both 
tractors and vocational vehicles, Class 7 tractors are considered 
medium heavy-duty ``MHD'' vehicles and Class 8 tractors are considered 
heavy heavy-duty ``HHD'' vehicles. This paragraph applies for both 
hybrid and non-hybrid vehicles.
    (2) Phase 1 vocational vehicles are divided based on GVWR. Light 
heavy-duty ``LHD'' vehicles includes Class 2b through Class 5 vehicles; 
medium heavy-duty ``MHD'' vehicles includes Class 6 and Class 7 
vehicles; and heavy heavy-duty ``HHD'' vehicles includes Class 8 
vehicles.
    (3) Phase 2 vocational vehicles with spark-ignition engines are 
divided based on GVWR. Light heavy-duty ``LHD'' vehicles includes Class 
2b through Class 5 vehicles, and medium heavy-duty ``MHD'' vehicles 
includes Class 6 through Class 8 vehicles.
    (4) Phase 2 vocational vehicles with compression-ignition engines 
are divided as follows:
    (i) Class 2b through Class 5 vehicles are considered light heavy-
duty ``LHD'' vehicles.
    (ii) Class 6 through 8 vehicles are considered heavy heavy-duty 
``HHD'' vehicles if the installed engine's primary intended service 
class is heavy heavy-duty (see 40 CFR 1036.140), except that Class 8 
hybrid vehicles are considered heavy heavy-duty ``HHD'' vehicles 
regardless of the engine's primary intended service class. All other 
Class 6 through Class 8 vehicles are considered medium heavy-duty 
``MHD'' vehicles.
    (5) Heavy-duty vehicles with no installed propulsion engine, such 
as electric vehicles, are divided as follows:
    (i) Class 2b through Class 5 vehicles are considered light heavy-
duty ``LHD'' vehicles.
    (ii) Class 6 and 7 vehicles are considered medium heavy-duty 
``MHD'' vehicles.
    (iii) Class 8 vehicles are considered heavy heavy-duty ``HHD'' 
vehicles.
    (6) In certain circumstances, manufacturers may certify vehicles to 
standards that apply for a different vehicle service class such as 
allowed in Sec.  535.5(b)(6) and (c)(7). If manufacturers optionally 
certify vehicles to different standards, those vehicles are subject to 
all the regulatory requirements as if the standards were mandatory.
    Vehicle subfamily or subfamily means a subset of a vehicle family 
including vehicles subject to the same FEL(s).
    Vocational tractor has the meaning given in 40 CFR 1037.801.
    Zero emissions vehicle means an electric vehicle or a fuel cell 
vehicle.

0
5. Amend Sec.  535.5 by:
0
a. Revising paragraphs (a) introductory text, (a)(1), and (b) 
introductory text;
0
b. Removing and reserving paragraph (b)(1)(iii)(B);
0
c. Revising paragraphs (b)(4), (b)(9)(i) introductory text, (c) 
introductory text, (c)(5), (d) introductory text, (d)(3), and 
(d)(11)(i)(A) and (C); and
0
d. Removing paragraph (e).
    The revisions read as follows:


Sec.  535.5  Standards.

    (a) Heavy-duty pickup trucks and vans. Each manufacturer's fleet of 
heavy-duty pickup trucks and vans shall comply with the fuel 
consumption standards in this paragraph (a) expressed in gallons per 
100 miles. Each vehicle must be manufactured to comply for its full 
useful life. For the Phase 1 program, if the manufacturer's fleet 
includes conventional vehicles (gasoline, diesel and alternative fueled 
vehicles) and advanced technology vehicles (hybrids with powertrain 
designs that include energy storage systems, vehicles with waste heat 
recovery, electric vehicles and fuel cell vehicles), it may divide its 
fleet into two separate fleets each with its own separate fleet average 
fuel consumption standard which the manufacturer must comply with the 
requirements of this paragraph (a). For Phase 2, manufacturers may 
calculate their fleet average fuel consumption standard for a 
conventional fleet and multiple advanced technology vehicle fleets. 
Advanced technology vehicle fleets should be separated into plug-in 
hybrid electric vehicles, electric vehicles, and fuel cell vehicles. 
The standards in this paragraph (a) correspond to EPA requirements 
specified in 40 CFR 86.1819-14. When applying the fuel consumption 
standards in this paragraph (a), manufacturers must use the same 
options they use to comply with EPA in 40 CFR part 86, subpart S in 
terms of grouping vehicles and/or engines for purposes of determining

[[Page 18826]]

applicable standards and determining compliance (i.e., the vehicles 
and/or engines and must be grouped in the same way for purposes of this 
paragraph (a) as they are grouped for compliance with EPA's 
requirements in 40 CFR part 86, subpart S). Engines that are installed 
in vehicles that are subject to the standards in this paragraph are not 
subject to the standards in paragraph (d) of this section and may not 
optionally comply with paragraph (d).
    (1) Mandatory standards. For model years 2016 and later, each 
manufacturer must comply with the fleet average standard derived from 
the unique subconfiguration target standards (or groups of 
subconfigurations approved by EPA in accordance with 40 CFR 86.1819-14) 
of the model types that make up the manufacturer's fleet in a given 
model year. Each subconfiguration has a unique attribute-based target 
standard, defined by each group of vehicles having the same payload, 
towing capacity and whether the vehicles are equipped with a 2-wheel or 
4-wheel drive configuration. Phase 1 target standards apply for model 
years 2016 through 2020. Phase 2 target standards apply for model year 
2021 and afterwards.
* * * * *
    (b) Heavy-duty vocational vehicles. Each manufacturer building 
complete or incomplete heavy-duty vocational vehicles shall comply with 
the fuel consumption standards in this paragraph (b) expressed in 
gallons per 1,000 ton-miles. When applying the fuel consumption 
standards in this paragraph (b), manufacturers must use the same 
options they use to comply with EPA in 40 CFR 1037.105 in terms of 
grouping vehicles and/or engines for purposes of determining applicable 
standards and determining compliance (i.e., the vehicles and/or engines 
and must be grouped in the same way for purposes of this paragraph (b) 
as they are grouped for compliance with EPA's requirements in 40 CFR 
1037.105). Engines used in heavy-duty vocational vehicles shall comply 
with the standards in paragraph (d) of this section. Each vehicle must 
be manufactured to comply for its full useful life. Standards apply to 
the vehicle subfamilies based upon the vehicle service classes within 
each of the vocational vehicle regulatory subcategories in accordance 
with Sec.  535.4 and based upon the applicable modeling and testing 
specified in Sec.  535.6. Determine the duty cycles that apply to 
vocational vehicles according to 40 CFR 1037.140 and 1037.150(z).
* * * * *
    (4) Regulatory subcategory standards for model years 2021 and 
later. The mandatory fuel consumption standards for heavy-duty 
vocational vehicles are given in the following table:

               Table 9 to Paragraph (b)(4)--Phase 2 Vocational Vehicle Fuel Consumption Standards
                                          [Gallons per 1,000 ton-miles]
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
                             Model Years 2021 through 2023 Standards for CI Vehicles
----------------------------------------------------------------------------------------------------------------
Duty cycle                                              LHD vocational         MHD vocational     Vocational HHD
                                                              vehicles               vehicles           vehicles
----------------------------------------------------------------------------------------------------------------
Urban..............................................            41.6503                29.0766            30.2554
Multi-Purpose......................................            36.6405                26.0314            25.6385
Regional...........................................            30.5501                22.9862            20.1375
----------------------------------------------------------------------------------------------------------------
                             Model Years 2021 through 2023 Standards for SI Vehicles
----------------------------------------------------------------------------------------------------------------
Duty cycle                                              LHD vocational            MHD and HHD                N/A
                                                              vehicles    vocational vehicles
----------------------------------------------------------------------------------------------------------------
Urban..............................................            51.8735                36.9078                N/A
Multi-Purpose......................................            45.7972                32.9695                N/A
Regional...........................................            37.6955                29.3687                N/A
----------------------------------------------------------------------------------------------------------------
                             Model Years 2024 through 2026 Standards for CI Vehicles
----------------------------------------------------------------------------------------------------------------
Duty cycle                                              Vocational LHD         Vocational MHD     Vocational HHD
                                                              vehicles               vehicles           vehicles
----------------------------------------------------------------------------------------------------------------
Urban..............................................            37.8193                26.6208            27.7996
Multi-Purpose......................................            33.7917                24.1650            23.7721
Regional...........................................            29.0766                21.7092            19.0570
----------------------------------------------------------------------------------------------------------------
                             Model Years 2024 through 2026 Standards for SI Vehicles
----------------------------------------------------------------------------------------------------------------
Duty cycle                                              Vocational LHD     Vocational MHD and                N/A
                                                              vehicles           HHD vehicles
----------------------------------------------------------------------------------------------------------------
Urban..............................................            48.6103                34.8824                N/A
Multi-Purpose......................................            43.3217                31.3942                N/A
Regional...........................................            36.4577                28.2435                N/A
----------------------------------------------------------------------------------------------------------------
                              Model Years 2027 and later Standards for CI Vehicles
----------------------------------------------------------------------------------------------------------------
Duty cycle                                              Vocational LHD         Vocational MHD     Vocational HHD
                                                              vehicles               vehicles           vehicles
----------------------------------------------------------------------------------------------------------------
Urban..............................................            36.0511                25.3438            26.4244
Multi-Purpose......................................            32.4165                23.0845            22.5933
Regional...........................................            28.5855                21.4145            18.5658
----------------------------------------------------------------------------------------------------------------

[[Page 18827]]

 
                              Model Years 2027 and later Standards for SI Vehicles
----------------------------------------------------------------------------------------------------------------
Duty cycle                                              Vocational LHD     Vocational MHD and                N/A
                                                              vehicles           HHD vehicles
----------------------------------------------------------------------------------------------------------------
Urban..............................................            46.4724                33.4196                N/A
Multi-Purpose......................................            41.8589                30.1564                N/A
Regional...........................................            35.8951                27.7934                N/A
----------------------------------------------------------------------------------------------------------------

* * * * *
    (9) * * *
    (i) Qualifying criteria. Vocational vehicles with a date of 
manufacture before January 1, 2021 automatically qualify for an 
exemption under this paragraph (b)(9) if the tires installed on the 
vehicle have a maximum speed rating at or below 55 miles per hour. 
Vocational vehicles intended for off-road use are exempt without 
request, subject to the provisions of this section, if they are 
primarily designed to perform work off-road (such as in oil fields, 
mining, forests, or construction sites), and they meet at least one of 
the criteria of paragraph (b)(9)(i)(A) of this section and at least one 
of the criteria of paragraph (b)(9)(i)(B) of this section. See 
paragraph (b)(6) of this section for alternate standards that apply for 
vehicles meeting only one of these sets of criteria.
* * * * *
    (c) Truck tractors. Each manufacturer building truck tractors, 
except vocational tractors or vehicle constructed in accordance with 49 
CFR 571.7(e), with a GVWR above 26,000 pounds shall comply with the 
fuel consumption standards in this paragraph (c) expressed in gallons 
per 1,000 ton-miles. When applying the fuel consumption standards in 
this paragraph (c), manufacturers must use the same options they use to 
comply with EPA in 40 CFR 1037.106 in terms of grouping vehicles and/or 
engines for purposes of determining applicable standards and 
determining compliance (i.e., the vehicles and/or engines and must be 
grouped in the same way for purposes of this paragraph (c) as they are 
grouped for compliance with EPA's requirements in 40 CFR 1037.106). 
Engines used in heavy-duty truck tractors vehicles shall comply with 
the standards in paragraph (d) of this section. Each vehicle must be 
manufactured to comply for its full useful life. Standards apply to the 
vehicle subfamilies within each of the tractor vehicle regulatory 
subcategories in accordance with Sec.  535.4 and 40 CFR 1037.230 and 
based upon the applicable modeling and testing specified in Sec.  
535.6. Determine the vehicles in each regulatory subcategory in 
accordance with 40 CFR 1037.140.
* * * * *
    (5) Alternate standards for tractors at or above 120,000 pounds 
GCWR. Manufacturers may certify tractors at or above 120,000 pounds 
GCWR to the following fuel consumption standards in the following 
table:

  Table 12 to Paragraph (c)(5)--Alternate Fuel Consumption Standards for Tractors Above 120,000 Pounds GCWR for
                                                2021 MY and Later
                                          [Gallons per 1,000 ton-miles]
----------------------------------------------------------------------------------------------------------------
                                                        Model years 2021     Model years 2024   Model years 2027
               Regulatory subcategory                     through 2023         through 2026         and later
----------------------------------------------------------------------------------------------------------------
Heavy Class 8 Low-Roof Day Cab......................              5.25540              4.99018           4.80354
Heavy Class 8 Low-Roof Sleeper Cab..................              4.62672              4.37132           4.16503
Heavy Class 8 Mid-Roof Day Cab......................              5.46169              5.18664           4.99018
Heavy Class 8 Mid-Roof Sleeper Cab..................              4.87230              4.60707           4.39096
Heavy Class 8 High-Roof Day Cab.....................              5.35363              5.04912           4.77407
Heavy Class 8 High-Roof Sleeper Cab.................              4.62672              4.34185           4.02750
----------------------------------------------------------------------------------------------------------------

* * * * *
    (d) Heavy-duty engines. Each manufacturer of heavy-duty engines 
shall comply with the fuel consumption standards in this paragraph (d) 
of this section expressed in gallons per 100 horsepower-hour. When 
applying the fuel consumption standards in this paragraph (d), 
manufacturers must use the same options they use to comply with EPA in 
40 CFR 1036.108 in terms of grouping engines for purposes of 
determining applicable standards and determining compliance (i.e., the 
engines must be grouped in the same way for part 535.5(d) purposes as 
they are grouped for compliance with EPA's requirements in 40 CFR 
1036.108). Each engine must be manufactured to comply for its full 
useful life, expressed in service miles, operating hours, or calendar 
years, whatever comes first. The provisions of this part apply to all 
new 2014 model year and later heavy-duty engines fueled by conventional 
and alternative fuels and manufactured for use in heavy-duty tractors 
or vocational vehicles. Standards apply to the engine and powertrain 
families and sub-families based upon the primary intended service 
classes within each of the engine regulatory subcategories as described 
in Sec.  535.4 and based upon the applicable modeling and testing 
specified in Sec.  535.6.
* * * * *
    (3) Regulatory subcategory standards. The primary fuel consumption 
standards for heavy-duty engine families are given in the following 
table:

[[Page 18828]]



               Table 13 to Paragraph (d)(3)--Primary Heavy-Duty Engine Fuel Consumption Standards
                                             [Gallons per 100 hp-hr]
----------------------------------------------------------------------------------------------------------------
                                          Phase 1--Voluntary Standards
-----------------------------------------------------------------------------------------------------------------
    Regulatory subcategory       CI LHD engines   CI MHD engines and all  HHD CI engines and all    SI engines
-------------------------------   and all other        other engines           other engines     ---------------
                                     engines     ------------------------------------------------
          Application          ------------------                                                       All
                                   Vocational      Vocational   Tractor    Vocational   Tractor
----------------------------------------------------------------------------------------------------------------
2015..........................  ................  ...........  .........  ...........  .........          7.0552
2013 through 2016.............            5.8939       5.8939     4.9312       5.5697      4.666  ..............
----------------------------------------------------------------------------------------------------------------


 
                                          Phase 1--Mandatory Standards
-----------------------------------------------------------------------------------------------------------------
    Regulatory subcategory       CI LHD engines   CI MHD engines and all  CI HHD engines and all    SI engines
-------------------------------   and all other        other engines           other engines     ---------------
                                     engines     ------------------------------------------------
          Application          ------------------                                                       All
                                   Vocational      Vocational   Tractor    Vocational   Tractor
----------------------------------------------------------------------------------------------------------------
2016..........................  ................  ...........  .........  ...........  .........          7.0552
2017 through 2020.............            5.6582       5.6582     4.7839       5.4519     4.5187          7.0552
----------------------------------------------------------------------------------------------------------------


 
                                          Phase 2--Mandatory Standards
-----------------------------------------------------------------------------------------------------------------
    Regulatory subcategory       CI LHD engines   CI MHD engines and all  CI HHD engines and all    SI engines
-------------------------------   and all other        other engines           other engines        (except HHD
                                     engines     ------------------------------------------------    engines)
          Application          ------------------                                                ---------------
                                   Vocational      Vocational   Tractor    Vocational   Tractor         All
----------------------------------------------------------------------------------------------------------------
2021 through 2023.............            5.5305       5.3536     4.6464       5.0393     4.3910          7.0552
2024 through 2026.............            5.4519       5.2849     4.5285       4.9705     4.2829          7.0552
2027 and Later................            5.4224       5.2554     4.4892       4.9411     4.2436          7.0552
----------------------------------------------------------------------------------------------------------------

* * * * *
    (11) * * *
    (i) * * *
    (A) 5.3241 gallons per 100 hp-hr for MHD vocational vehicle 
engines.
* * * * *
    (C) 5.0098 gallons per 100 hp-hr for HHD vocational vehicle 
engines.
* * * * *

0
6. Amend Sec.  535.6 by:
0
a. Revising paragraphs (b)(1), (b)(4)(ii), and (b)(5)(i);
0
b. Adding paragraphs (b)(5)(v)(E)(3) and (4)
0
c. Revising paragraphs (d) introductory text, (d)(1), (d)(2) 
introductory text, (d)(3) introductory text, and (d)(3)(ii) 
introductory text; and
0
d. Removing paragraph (e).
    The revisions and additions read as follows:


Sec.  535.6  Measurement and calculation procedures.

* * * * *
    (b) * * *
    (1) Select vehicles and vehicle family configurations as specified 
in 40 CFR 1037.150 and 1037.230 for vehicles that make up each of the 
manufacturer's regulatory subcategories of vocational vehicles and 
tractors. For the Phase 2 program, select powertrain, axle and 
transmission families in accordance with 40 CFR 1037.231 and 1037.232.
* * * * *
    (4) * * *
    (ii) Coefficient of aerodynamic drag (CdA) or drag area, 
as described in 40 CFR 1037.520(b), 1037.525, 1037.527, and 1037.528. 
Alternatively, manufacturers may use CdA values as specified 
in 40 CFR 1037.530, 1037.532, or 1037.534 if used for determining 
CO2 compliance for EPA. Manufacturers must use the same 
compliance approach for determining CdA values in GEM for 
the NHTSA and EPA programs.
* * * * *
    (5) * * *
    (i) Engine characteristics. Enter information from the engine 
manufacturer to describe the installed engine and its operating 
parameters as described in 40 CFR 1036.503 and 1037.520(f).
* * * * *
    (v) * * *
    (E) * * *
    (3) Manufacturers may use values to characterize torque converters 
as inputs to GEM as specified in the procedure defined in 40 CFR 
1037.570.
    (4) Vocational vehicle manufacturers may optionally use values for 
neutral coasting in GEM as specified in 40 CFR 1037.520
* * * * *
    (d) Heavy-duty engines. This section describes the method for 
determining equivalent fuel consumption family certification level 
(FCL) values for engine and powertrain families and subfamilies of 
heavy-duty truck tractors and vocational vehicles. The NHTSA heavy-duty 
engine fuel consumption FCLs are determined from the EPA FCLs tested in 
accordance with 40 CFR part 1036, subpart F. Each engine and powertrain 
family must use the same primary intended service class as designated 
for EPA in accordance with 40 CFR 1036.140.
    (1) Manufacturers must select emission-data engines representing 
the tested configuration of each engine family specified in 40 CFR 
1036.501 for engines in heavy-duty truck tractors and vocational 
vehicles that make up each of the manufacturer's regulatory 
subcategories.
    (2) Standards in Sec.  535.5(d) apply to the CO2 emissions rates 
for each emissions-data engine in an engine or powertrain family or 
sub-family subject to the procedures and equipment specified in 40 CFR 
part 1036, subpart F. Determine equivalent fuel consumptions rates 
using CO2 emissions rates in grams per hp-hr measured to at least one 
more decimal place than that of the applicable EPA standard in 40 CFR 
1036.108.
* * * * *
    (3) For medium HD and heavy HD engines certified as tractor and 
other long-haul engine families, use the CO2 emissions test results 
from the steady-state duty cycle, which is referred to as the 
Supplemental Emission Test (SET), as specified in 40 CFR 1036.510 for 
each model year; for medium HD and heavy HD engines certified as 
tractor and vocational engine families, use the CO2 test results from 
the transient duty

[[Page 18829]]

cycle, which is referred to as the Federal Test Procedure (FTP) duty 
cycle, as specified in 40 CFR 1036.512 for each model year; for all 
other engines (including those certifying to SI standards) use the CO2 
emissions test results from the appropriate duty cycle, as specified in 
40 CFR 1036.501 for each model year.
* * * * *
    (ii) The following engines are excluded from the engine and 
powertrain families and subfamilies used to determine fuel consumption 
FCL values and the benefit for these engines is determined as an 
advanced technology credit under the ABT provisions provided in Sec.  
535.7(e); these provisions apply only for the Phase 1 program:
* * * * *

0
7. Amend Sec.  535.7 by:
0
a. Revising paragraphs (a) introductory text and (a)(2)(v);
0
b. Removing paragraph (a)(3)(v);
0
c. Revising paragraph (a)(4) introductory text;
0
d. Removing and reserving paragraph (a)(4)(v);
0
e. Revising paragraphs (a)(8)(i) and (a)(9)(iv)(B);
0
f. Adding paragraph (a)(11);
0
g. Revising paragraphs (b)(1), (c)(1) introductory text, (d)(1) 
introductory text, and (d)(7);
0
h. Removing and reserving paragraph (e);
0
i. Revising paragraph (f)(1)(ii) introductory text;
0
j. Adding paragraph (f)(1)(ii)(G); and
0
k. Removing and reserving paragraph (f)(2)(v).
    The revisions and additions read as follows:


Sec.  535.7  Averaging, banking, and trading (ABT) credit program.

    (a) General provisions. After the end of each model year, 
manufacturers must comply with the fuel consumption standards in Sec.  
535.5 for averaging, banking and trading credits. Manufacturers comply 
with standards if the sum of averaged, banked and traded credits 
generate a ``zero'' credit balance or a credit surplus within an 
averaging set of vehicles or engines. Manufacturers fail to comply with 
standards if the sum of the credit flexibilities generate a credit 
deficit (or shortfall) in an averaging set. Credit shortfalls must be 
offset by banked or traded credits within three model years after the 
shortfall is incurred. These processes are hereafter referenced as the 
NHTSA ABT credit program. The following provisions apply to all fuel 
consumption credits.
* * * * *
    (2) * * *
    (v) If a manufacturer certifies a vehicle family to an FEL that 
exceeds the otherwise applicable standard, it must obtain enough FCC to 
offset the vehicle family's deficit by the due date of its final report 
required in Sec.  535.8. The emission credits used to address the 
deficit may come from other vehicle families that generate FCCs in the 
same model year (or from the next three subsequent model years), from 
banked FCCs from previous model years, or from FCCs generated in the 
same or previous model years that it obtained through trading.
* * * * *
    (4) Trading. Trading is a transaction that transfers banked family 
regulatory subcategory or averaging set fuel consumption credits. 
Tractor, vocational vehicle and engine manufacturers may trade credits 
generated for vehicle or engine families or subfamilies while 
manufacturers of heavy-duty pickup trucks and vans certified as 
complete vehicles may trade credit credits generated for averaging 
sets. A manufacturer may use traded FCCs for averaging, banking, or 
further trading transactions.
    (8) * * *
    (i) Fuel consumption credits a manufacturer generates for light and 
medium heavy-duty vocational vehicles in model years 2018 through 2021 
may be used through model year 2027, instead of being limited to a 
five-year credit life as specified in this part. Fuel consumption 
credits that small manufacturers generate for heavy heavy-duty 
vocational vehicles in model years 2018 through may be used through 
model year 2027, instead of being limited to a five-year credit life as 
specified in this part. Fuel consumption credits that a small 
manufacturer generates for vocational vehicles in model year 2022 that 
are certified to Phase 1 standards as permitted under Sec.  
535.3(e)(2)(ii)(B) may be used through model year 2027.
* * * * *
    (9) * * *
    (iv) * * *
    (B) Manufacturers may produce up to 200 drayage tractors in a given 
model year to the standards described in Sec.  535.5(b)(6) for ``other 
buses''. Treat these drayage tractors as being in their own averaging 
set. This limit applies with respect to vehicles produced by 
manufacturers within a control relationship as defined Sec.  534.3.
* * * * *
    (11) Fuel consumption credits may not be generated more than once. 
This means that fuel consumption credits may only be generated once for 
a given engine or vehicle and fuel consumption credits may not be 
generated for both a given engine and the vehicle in which the engine 
is installed. For example, if a manufacturer generates fuel consumption 
credits for a given hybrid vehicle under this part, no one may generate 
fuel consumption credits for the associated hybrid engine. This 
provision, however, does not prevent manufacturers from generating fuel 
consumption credits for engines that are identical to the given engine 
in the example if those engines are installed in vehicles for which 
fuel consumption credits are not generated. This provision does not 
impact any adjustment factor or multiplier that is applied to the fuel 
consumption credits as specified or permitted by this part.
    (b) * * *
    (1) Calculate fuel consumption credits in a model year for one 
fleet of conventional heavy-duty pickup trucks and vans and if 
designated by the manufacturer another consisting of advance technology 
vehicles for the averaging set as defined in Sec.  535.4. Calculate 
credits for each fleet separately using the following equation:

Total MY Fleet FCC (gallons) = (Std-Act) x (Volume) x (UL) x (10\2\)

Where:

Std = Fleet average fuel consumption standard (gal/100 mile).
Act = Fleet average actual fuel consumption value (gal/100 mile).
Volume = the total U.S.-directed production of vehicles in the 
regulatory subcategory.
UL = the useful life for the regulatory subcategory. The useful life 
value for heavy- pickup trucks and vans manufactured for model years 
2013 through 2020 is equal to the 120,000 miles. The useful life for 
model years 2021 and later is equal to 150,000 miles.
* * * * *
    (c) * * *
    (1) Calculate the fuel consumption credits in a model year for each 
participating family or subfamily consisting of conventional vehicles 
in each averaging set (as defined in Sec.  535.4) using the equation in 
this section. Each designated vehicle family or subfamily has a 
``family emissions limit'' (FEL) that is compared to the associated 
regulatory subcategory standard. An FEL that falls below the regulatory 
subcategory standard creates ``positive credits,'' while fuel 
consumption level of a family group above the standard creates a 
``negative credits.'' The value of credits generated for each family or 
subfamily in a model year is calculated as follows and must be rounded 
to nearest whole number:

[[Page 18830]]

Vehicle Family FCC (gallons) = (Std-FEL) x (Payload) x (Volume) x (UL) 
x (10\3\)

Where:
Std = the standard for the respective vehicle family regulatory 
subcategory (gal/1,000 ton-mile).
FEL = family emissions limit for the vehicle family (gal/1,000 ton-
mile).
Payload = the prescribed payload in tons for each regulatory 
subcategory as shown in the following table:

              Table 1 to Paragraph (c)(1) Introductory Text
------------------------------------------------------------------------
                                                              Payload
                 Regulatory subcategory                       (tons)
------------------------------------------------------------------------
Vocational LHD Vehicles.................................            2.85
Vocational MHD Vehicles.................................            5.60
Vocational HHD Vehicles.................................             7.5
MDH MHD Tractors........................................           12.50
HHD Tractors, other than heavy-haul Tractors............           19.00
Heavy-haul Tractors.....................................           43.00
------------------------------------------------------------------------

Volume = the number of U.S.-directed production volume of vehicles 
in the corresponding vehicle family.
UL = the useful life for the regulatory subcategory (miles) as shown 
in the following table:

              Table 2 to Paragraph (c)(1) Introductory Text
------------------------------------------------------------------------
             Regulatory subcategory                     UL  (miles)
------------------------------------------------------------------------
LHD Vehicles....................................  110,000 (Phase
                                                   1);150,000 (Phase 2).
Vocational MHD Vehicles and tractors at or below  185,000.
 33,000 pounds GVWR.
Vocational HHD Vehicles and tractors at or above  435,000.
 33,000 pounds GVWR.
------------------------------------------------------------------------

* * * * *
    (d) * * *
    (1) Calculate the fuel consumption credits in a model year for each 
participating family or subfamily consisting of engines in each 
averaging set (as defined in Sec.  535.4) using the equation in this 
section. Each designated engine family has a ``family certification 
level'' (FCL) which is compared to the associated regulatory 
subcategory standard. A FCL that falls below the regulatory subcategory 
standard creates ``positive credits,'' while fuel consumption level of 
a family group above the standard creates a ``credit shortfall.'' The 
value of credits generated in a model year for each engine family or 
subfamily is calculated as follows and must be rounded to nearest whole 
number:

Engine Family FCC (gallons) = (Std-FCL) x (CF) x(Volume) x (UL) x 
(10\2\)

Where:

Std = the standard for the respective engine regulatory subcategory 
(gal/100 hp-hr).
FCL = family certification level for the engine family (gal/100 hp-
hr).
CF= a transient cycle conversion factor in hp-hr/mile which is the 
integrated total cycle horsepower-hour divided by the equivalent 
mileage of the applicable test cycle. For engines subject to spark-
ignition heavy-duty standards, the equivalent mileage is 6.3 miles. 
For engines subject to compression-ignition heavy-duty standards, 
the equivalent mileage is 6.5 miles.
Volume = the number of engines in the corresponding engine family.
UL = the useful life of the given engine family (miles) as shown in 
the following table:

              Table 3 to Paragraph (d)(1) Introductory Text
------------------------------------------------------------------------
             Regulatory Subcategory                     UL  (miles)
------------------------------------------------------------------------
SI and CI LHD Engines...........................  120,000 (Phase 1);
                                                   150,000 (Phase 2).
CI MHD Engines..................................  185,000.
CI HHD Engines..................................  435,000.
------------------------------------------------------------------------

* * * * *
    (7) Engine credits generated for compression-ignition engines in 
model year 2020 and earlier may be used in model year 2021 and later as 
follows:
    (i) For credit-generating engines certified to the tractor engine 
standards in Sec.  535.5(d), you may use credits calculated relative to 
the tractor engine standards.
    (ii) For credit-generating engines certified to the vocational 
engine standards in Sec.  535.5(d), you may use credits calculated 
relative to the following family certification levels (FCLs):
    (A) Medium Heavy-Duty Engines = 5.4813 gallons/100 hp-hr
    (B) Heavy Heavy-Duty Engines = 5.1572 gallons/100 hp-hr
    (C) To transfer Phase 1 credits for use in the Phase 2 fuel 
consumption program, manufacturers must recalculate credit values for 
the Phase 1 model years by substituting the FCLs in paragraph (d)(1) of 
this section with the those in paragraphs (d)(7)(ii)(A) and (B) of this 
section.
* * * * *
    (f) * * *
    (1) * * *
    (ii) There are no separate credit allowances for advanced 
technology vehicles in the Phase 2 program. Instead, through model year 
2027, vehicle families containing plug-in battery electric hybrids, 
all-electric, and fuel cell vehicles certifying to Phase 2 vocational 
and tractor standards may multiply credits by a multiplier of:
* * * * *
    (G) Advanced technology credits increased with a multiplier in 
Phase 2,

[[Page 18831]]

in accordance with Sec.  535.7(f)(1)(ii), cannot be used across 
averaging sets.
* * * * *

0
8. Amend Sec.  535.8 by revising paragraphs (a)(6), (g)(11)(i)(C), 
(g)(12), and (i) to read as follows:


Sec.  535.8  Reporting and recordkeeping requirements.

    (a) * * *
    (6) Any information that must be sent directly to NHTSA. In 
instances in which EPA has not created an electronic pathway to receive 
the information, the information should be sent through an electronic 
portal identified by NHTSA or through the NHTSA CAFE database (i.e., 
information on fuel consumption credit transactions). If hardcopy 
documents must be sent, the information should be sent to the Associate 
Administrator of Enforcement at 1200 New Jersey Avenue SE, NVS-200, 
Office W45-306, Washington, DC 20590.
* * * * *
    (g) * * *
    (11) * * *
    (i) * * *
    (C) The averaging set corresponding to the engine and powertrain 
families and subfamilies that generated fuel consumption credits for 
the trade, including the number of fuel consumption credits from each 
averaging set.
* * * * *
    (12) Production reports. Within 90 days after the end of the model 
year and no later than March 31st, manufacturers participating and not-
participating in the ABT program must send to EPA and NHTSA a report 
including the total U.S.-directed production volume of vehicles it 
produced in each vehicle and engine family during the model year (based 
on information available at the time of the report) as required by 40 
CFR 1036.250 and 1037.250. Each manufacturer shall report by vehicle or 
engine identification number and by configuration and identify the 
subfamily identifier. Report uncertified vehicles sold to secondary 
vehicle manufacturers. Small business manufacturers may omit reporting. 
Identify any differences between volumes included for EPA but excluded 
for NHTSA.
* * * * *
    (i) Information received from EPA. NHTSA will receive information 
from EPA as specified in 40 CFR 1036.755 and 1037.755. The knowing and 
willful submission of false, fictitious or fraudulent information under 
this part will subject a manufacturer to the civil and criminal 
penalties of 18 U.S.C. 1001.
* * * * *

0
9. Amend Sec.  535.9 by revising paragraph (a)(1)(i) and adding 
paragraph (a)(1)(v) to read as follows:


Sec.  535.9  Enforcement approach.

    (a) * * *
    (1) * * *
    (i) NHTSA may conduct audits or confirmatory testing on any 
configuration prior to first sale throughout a given model year or 
after the model year in order to validate data received from 
manufacturers and will discuss any potential issues with EPA and the 
manufacturer. NHTSA may perform confirmatory testing. Any such testing 
would be performed as specified in EPA's regulations at 40 CFR part 
1037. Audits may periodically be performed to confirm manufacturers' 
credit balances, or other credit transactions or other information 
submitted to EPA and NHTSA.
* * * * *
    (v) NHTSA may require a manufacturer to perform selective 
enforcement audits with respect to any GEM inputs in its application 
for certification or in the end of the year ABT final reports. Any 
required selective enforcement audits would be required to be conducted 
in a manner consistent with EPA's corresponding provisions at 40 CFR 
1037.301, 1037.305, and 1037.320.
* * * * *

0
10. Amend Sec.  535.10 by:
0
a. Removing and reserving paragraph (a)(3);
0
b. Revising paragraphs (a)(6) and (c)(2); and
0
c. Removing and reserving paragraph (c)(3).
    The revisions read as follows:


Sec.  535.10  How do manufacturers comply with fuel consumption 
standards?

    (a) * * *
    (6) Manufacturers apply the fuel consumption standards specified in 
Sec.  535.5 to vehicles, engines and components that represent 
production units and components for vehicle and engine families, 
subfamilies and configurations consistent with the EPA specifications 
in 40 CFR 86.1819, 1036.230, and 1037.230. Vehicles required to meet 
the fuel consumption standards of this part must also comply with the 
following additional requirements, consistent with CFR 1037.115(a) and 
(d):
    (i) Adjustable parameters. Vehicles that have adjustable parameters 
must meet all the requirements of this part for any adjustment in the 
practically adjustable range. We may require that you set adjustable 
parameters to any specification within the practically adjustable range 
during any testing. See 40 CFR 1068.50 for general provisions related 
to adjustable parameters. You must ensure safe vehicle operation 
throughout the practically adjustable range of each adjustable 
parameter, including consideration of production tolerances. Note that 
adjustable roof fairings and trailer rear fairings are deemed not to be 
adjustable parameters.
    (ii) Defeat devices. Consistent with 40 CFR 1068.101, the use of 
defeat devices is prohibited.
* * * * *
    (c) * * *
    (2) For truck tractors, vocational vehicles, and engines the 
manufacturer's fuel consumption performance for each vehicle or engine 
family (or subfamily), as determined in Sec.  535.6, is lower than the 
applicable regulatory subcategory standards in Sec.  535.5.
* * * * *

    Issued in Washington, DC, under authority delegated in 49 CFR 
1.95 and 501.5.
Sophie Shulman,
Deputy Administrator.
[FR Doc. 2024-05010 Filed 3-14-24; 8:45 am]
BILLING CODE 4910-59-P