Incomplete vehicle has the meaning given in 49 CFR 567.3.
    Innovative technology means technology certified under 40 CFR
1036.610, 40 CFR 1037.610 and 49 CFR 535.7(f).
    Light truck means a non-passenger automobile meeting the criteria
in Sec.  523.5.
    Manufacturer has the meaning in 49 U.S.C. 30102.
    Medium duty passenger vehicle means a vehicle which would satisfy
the criteria in Sec.  523.5 (relating to light trucks) but for its
gross vehicle weight rating or its curb weight, which is rated at more
than 8,500 lbs GVWR or has a vehicle curb weight of more than 6,000
pounds or has a basic vehicle frontal area in excess of 45 square feet,
and which is designed primarily to transport passengers, but does not
include a vehicle that--
    (1) Is an ``incomplete vehicle''' as defined in this subpart; or
    (2) Has a seating capacity of more than 12 persons; or
    (3) Is designed for more than 9 persons in seating rearward of the
driver's seat; or
    (4) Is equipped with an open cargo area (for example, a pick-up
truck box or bed) of 72.0 inches in interior length or more. A covered
box not readily accessible from the passenger compartment will be
considered an open cargo area for purposes of this definition.
    Mild hybrid gasoline-electric vehicle means a vehicle as defined by
EPA in 40 CFR 86.1866-12(e).
    Motor home has the meaning given in 49 CFR 571.3.
    Motor vehicle has the meaning giving in 49 U.S.C. 30102.
    Off-cycle technology means technology certified under 40 CFR
1036.610, 40 CFR 1037.610 and 49 CFR 535.7(f).
    Passenger-carrying volume means the sum of the front seat volume
and, if any, rear seat volume, as defined in 40 CFR 600.315-08, in the
case of automobiles to which that term applies. With respect to
automobiles to which that term does not apply, ``passenger-carrying
volume'' means the sum in cubic feet, rounded to the nearest 0.1 cubic
feet, of the volume of a vehicle's front seat and seats to the rear of
the front seat, as applicable, calculated as follows with the head
room, shoulder room, and leg room dimensions determined in accordance
with the procedures outlined in Society of Automotive Engineers
Recommended Practice J1100, Motor Vehicle Dimensions (Report of Human
Factors Engineering Committee, Society of Automotive Engineers,
approved November 2009).
    (1) For front seat volume, divide 1,728 into the product of the
following SAE dimensions, measured in inches to the nearest 0.1 inches,
and round the quotient to the nearest 0.001 cubic feet.

    (i) H61-Effective head room--front.
    (ii) W3-Shoulder room--front.
    (iii) L34-Maximum effective leg room-accelerator.
    (2) For the volume of seats to the rear of the front seat, divide
1,728 into the product of the following SAE dimensions, measured in
inches to the nearest 0.1 inches, and rounded the quotient to the
nearest 0.001 cubic feet.
    (i) H63-Effective head room--second.
    (ii) W4-Shoulder room--second.
    (iii) L51-Minimum effective leg room--second.
    Phase 1 means the greenhouse gas emissions standards and fuel
efficiency standards for medium- and heavy-duty engines and vehicles
program published in 2011, effective beginning with model year 2013.
    Phase 2 means means the greenhouse gas emissions standards and fuel
efficiency standards for medium- and heavy-duty engines and vehicles
program effective beginning with model year 2018 for heavy-duty
trailers and model year 2021 for all other heavy-duty vehicles and
engines.
    Pickup truck means a non-passenger automobile which has a passenger
compartment and an open cargo area (bed).
    Recreational vehicle or RV means a motor vehicle equipped with
living space and amenities found in a motor home.
    Running clearance means the distance from the surface on which an
automobile is standing to the lowest point on the automobile, excluding
unsprung weight.
    Static loaded radius arc means a portion of a circle whose center
is the center of a standard tire-rim combination of an automobile and
whose radius is the distance from that center to the level surface on
which the automobile is standing, measured with the automobile at curb
weight, the wheel parallel to the vehicle's longitudinal centerline,
and the tire inflated to the manufacturer's recommended pressure.
    Strong hybrid gasoline-electric vehicle means a vehicle as defined
by EPA in 40 CFR 86.1866-12(e).
    Temporary living quarters means a space in the interior of an
automobile in which people may temporarily live and which includes
sleeping surfaces, such as beds, and household conveniences, such as a
sink, stove, refrigerator, or toilet.
    Transmission class has the meaning given in 40 CFR 600.002.
    Tranmission configuration has the meaning given in 40 CFR 600.002.
    Transmission type has the meaning given in 40 CFR 86.1803.
    Van means a vehicle with a body that fully encloses the driver and
a cargo carrying or work performing compartment. The distance from the
leading edge of the windshield to the foremost body section of vans is
typically shorter than that of pickup trucks and sport utility
vehicles.
    Vocational tractor means a tractor that is classified as a
vocational vehicle according to 40 CFR 1037.630
    Vocational vehicle means a vehicle that is equipped for a
particular industry, trade or occupation such as construction, heavy
hauling, mining, logging, oil fields, refuse and includes vehicles such
as school buses, motorcoaches and RVs.
    Work truck means a vehicle that is rated at more than 8,500 pounds
and less than or equal to 10,000 pounds gross vehicle weight, and is
not a medium-duty passenger vehicle as defined in 40 CFR 86.1803.
0
284. Revise Sec.  523.6 to read as follows:

Sec.  523.6  Heavy-duty vehicle.

    (a) A heavy-duty vehicle is any commercial medium or heavy-duty on-
highway vehicle or a work truck, as defined in 49 U.S.C. 32901(a)(7)
and (19). For the purpose of this section, heavy-duty vehicles are
divided into four regulatory categories as follows:
    (1) Heavy-duty pickup trucks and vans;
    (2) Heavy-duty vocational vehicles;
    (3) Truck tractors with a GVWR above 26,000 pounds; and
    (4) Heavy-duty trailers.
    (b) The heavy-duty vehicle classification does not include vehicles
excluded as specified in 49 CFR 535.3.
0
285. Revise Sec.  523.7 to read as follows:

Sec.  523.7  Heavy-duty pickup trucks and vans.

    Heavy-duty pickup trucks and vans are pickup trucks and vans with a
gross vehicle weight rating between 8,501 pounds and 14,000 pounds
(Class 2b through 3 vehicles) manufactured as complete vehicles by a
single or final stage manufacturer or manufactured as incomplete
vehicles as designated by a manufacturer. A manufacturer may also
optionally designate as a heavy-duty pickup truck or van any cab-
complete or complete vehicle having a GVWR over 14,000 pounds and below
26,001 pounds equipped with a spark ignition engine or any spark
ignition engine certified and sold as a loose engine manufactured for
use in a heavy-duty pickup truck or van. See references in 40 CFR
86.1819, 40 CFR 1037.150, and 49 CFR 535.5(a).
0
286. Add Sec.  523.10 to read as follows:

Sec.  523.10  Heavy-duty trailers.

    (a) A trailer means a motor vehicle with or without motive power,
designed for carrying persons or property and for being drawn by
another motor vehicle as defined in 49 CFR 571.3. For the purpose of
this part, heavy-duty trailers include only those trailers designed to
be drawn by a truck tractor or vocational tractor. Heavy-duty trailers
may be divided into different types and categories as follows:
    (1) Box vans are trailers with an enclosed cargo space that is
permanently attached to the chassis, with fixed sides, nose, and roof
and is designed to carry a wide range of freight. Tankers are not box
vans.
    (2) Box vans with self-contained refrigeration systems are
refrigerated vans. All other box vans are dry vans.
    (3) Trailers that are not box vans are non-box trailers. This
includes chassis that are designed only for temporarily mounted
containers.
    (4) Box trailers with length greater than 50 feet are long box
trailers. Other box trailers are short box trailers.
    (b) Heavy-duty trailers does not include excluded trailers as
specified in 49 CFR 535.3.

PART 534--RIGHTS AND RESPONSIBILITIES OF MANUFACTURERS IN THE
CONTEXT OF CHANGES IN CORPORATE RELATIONSHIPS

0
287. Revise the authority citation for part 534 to read as follows:

    Authority:  49 U.S.C. 32901; delegation of authority at 49 CFR
1.95.
0
288. Add Sec.  534.8 to read as follows:

Sec.  534.8  Shared corporate relationships.

    (a) Vehicles and engines built by multiple manufacturers can share
responsibility for complying with fuel consumption standards in 49 CFR
part 535, if allowed by EPA under 40 CFR 1037.620 and a joint agreement
between the parties is sent to EPA and NHTSA.
    (1) Each agreement must--
    (i) Define how the vehicles and engines will be divided among each
manufacturer;
    (ii) Specify which manufacturer(s) will be responsible for the EPA
certificates of conformity required in 40 CFR 1036.201 and 40 CFR
1037.201;
    (iii) Describe the vehicles and engines in terms of the model
types, production volumes, and model years (production periods if
necessary);
    (iv) Describe which manufacturer(s) have engineering and design
control and sale distribution ownership over the vehicles and/or
engines; and

    (v) Include signatures from all parties involved in the shared
corporate relationship.
    (2) After defining the shared relationship between the
manufacturers for the initiating model year, manufacturers cannot
change the defined ownerships for subsequent model years unless one
manufacturer assumes a successor relationship over another manufacturer
that previously shared ownership.
    (3) Multiple manufacturers must designate the same shared
responsibility for complying with fuel consumption as selected for GHG
standards unless otherwise allowed by EPA and NHTSA.
    (b) NHTSA reserves the right to reject the joint agreement.
0
289. Revise part 535 to read as follows:

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

Sec.
535.1 Scope.
535.2 Purpose.
535.3 Applicability.
535.4 Definitions.
535.5 Standards.
535.6 Measurement and calculation procedures.
535.7 Averaging, banking, and trading (ABT) credit program.
535.8 Reporting requirements and recordkeeping requirements.
535.9 Enforcement approach.
535.10 How do manufacturers comply with fuel consumption standards?

    Authority:  49 U.S.C. 32902 and 30101; delegation of authority
at 49 CFR 1.95.

Sec.  535.1  Scope.

    This part establishes fuel consumption standards pursuant to 49
U.S.C. 32902(k) for work trucks and commercial medium-duty and heavy-
duty on-highway vehicles, including trailers (hereafter referenced as
heavy-duty vehicles), and engines manufactured for sale in the United
States and establishes a credit program 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.

Sec.  535.2  Purpose.

    The purpose of this part is to reduce the fuel consumption of new
heavy-duty vehicles by establishing maximum levels for fuel consumption
standards while providing a flexible credit program to assist
manufacturers in complying with standards.

Sec.  535.3  Applicability.

    (a) This part applies to manufacturers that produce complete and
incomplete heavy-duty vehicles as defined in 49 CFR part 523, and to
the manufacturers of all heavy-duty engines manufactured for use in the
applicable vehicles for each given model year.
    (b) Vehicle and engine manufacturers that must comply with this
part include manufacturers required to have approved certificates of
conformity from EPA as specified in 40 CFR parts 86, 1036, and 1037,
except for minor differences in excluded vehicles as specified in
paragraph (d) of this section.
    (c) In certain special conditions where EPA allows manufacturers to
designate other manufacturers to comply with GHG standards or grants
special allowances in the construction of vehicles, as specified in 40
CFR 1037.620, 1037.621, and 1037.650, these allowances can be used to
comply with the fuel consumption standards of this part.
    (d) Manufacturers required to meet the fuel consumption standards
of this part also include manufacturers completing, altering, or
assembling motor vehicles or motor vehicle equipment into--
    (1) Electric vehicles; and
    (2) Alternative fueled vehicles from all types of heavy duty engine
conversions.
    (i) Entities that install alternative fuel conversion systems into
vehicles acquired from vehicle manufacturers prior to first retail sale
or introduction into interstate commerce may be regulated under this
part if designated by the vehicle manufacturer and EPA to be the
certificate holder.
    (ii) Entities installing alternative fuel conversions are regulated
as vehicle and engine manufacturers.
    (iii) Entities can be omitted from compliance with vehicle based
standards, if-
    (A) Allowed by EPA;
    (B) They provide a reasonable technical basis that the modified
vehicle continues to meet vehicle standards; and
    (C) They provide a joint agreement to EPA and NHTSA as specified in
49 CFR 534.7.
    (e) The following heavy-duty vehicles and engines are excluded from
the requirements of this part:
    (1) Medium-duty passenger vehicles and other vehicles subject to
the light-duty corporate average fuel economy standards in 49 CFR parts
531 and 533.
    (2) Recreational vehicles, including motor homes manufactured
before model year 2021 exept those produced by manufacturers
voluntarily complying with NHTSA's early voational standards for model
years 2013 through 2020.
    (3) Heavy-duty trailers meeting one or more of the following
criteria are excluded from vehicle standards in Sec.  535.5(e):
    (i) Trailers designed for in-field operations in logging or mining.
    (ii) Trailers designed to operate at low speeds such that they are
unsuitable for normal highway operation.
    (iii) Trailers designed to perform their primary function while
stationary, if they have permanently affixed components designed for
heavy construction. This would include crane trailers and concrete
trailers. Trailers would not qualify under this paragraph based on
welding equipment or other components that are commonly used separate
from trailers.
    (iv) Trailers less than 35 feet long with three axles, and all
trailers with four or more axles.
    (v) Trailers intended for temporary or permanent residence, office
space, or other work space, such as campers, mobile homes, and carnival
trailers.
    (vi) Trailers built before January 1, 2021, except those trailers
voluntarily complaying with NHTSA's early trailer standards for model
years 2018-2020.
    (vii) Equipment that serves similar purposes to trailers but is not
intended to be pulled by a tractor.
    (viii) Containers that are not permanently mounted on chassis.
    (ix) Trailers designed to be drawn by vehicles other than tractors,
and those that are coupled to vehicles with pintle hooks or hitches
instead of a fifth wheel.
    (f) The following heavy-duty vehicles and engines are exempted from
the requirements of this part:
    (1) Off-road vehicles. Manufacturers producing heavy-duty
vocational vehicles or vocational tractors that are intended for off-
road use meeting the criteria of paragraph (f)(1)(i) of this section
are exempted from vehicle standards in Sec.  535.5(b) and (c) but must
comply with engine standards in Sec.  535.5(d).
    (i) Vehicles primarily designed to perform work off-road (such as
in oil fields, mining, forests, or construction sites), and meeting at
least one of the criteria of paragraph (f)(1)(i)(A) of this section and
at least one of the criteria of paragraph (f)(1)(i)(B) of this section.
    (A) Vehicle must have affixed components designed to work in an
off-road environment (for example, hazardous material equipment or
drilling equipment) or was designed to operate at low speeds making
them unsuitable for normal highway operation.

    (B) Vehicles must--
    (1) Have an axle that has a gross axle weight rating (GAWR) of
29,000 pounds or more;
    (2) Have a speed attainable in 2 miles of not more than 33 mph; or
    (3) Have a speed attainable in 2 miles of not more than 45 mph, an
unloaded vehicle weight that is not less than 95 percent of its gross
vehicle weight rating (GVWR), and no capacity to carry occupants other
than the driver and operating crew.
    (C) Manufacturers building tractors exempted under this provision
must request preliminary approval before introducing vehicles into
commerce. The request with supporting information must be sent to EPA
that will coordinate with NHTSA in making a determination in accordance
with 40 CFR 1037.210. Vehicles introduced into U.S. commerce without
approval under this paragraph violate 40 CFR 1068.101(a)(1).
    (ii) [Reserved]
    (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), 40 CFR
1036.150, and 40 CFR 1037.150. Qualifying manufacturers of truck
tractors, vocational vehicles, heavy duty pickups and vans, and engines
are not subject to the fuel consumption standards for vehicles and
engines built before January 1, 2022. Qualifying manufacturers may
choose to voluntarily comply early.
    (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), 40 CFR 1036.150, and 40 CFR 1037.150 may delay complying with
every new mandatory standard under this part by one model year.
    (g) For model year 2021 and later, emergency vehicles may comply
with alternative fuel consumption standards as specified in Sec.
535.5(b)(5) instead of the standards specified in Sec.  535.5(b)(4).
Vehicles certified to these alternative standards may not generate or
use positive fuel consumption credits but negative credits must be
averaged within an averaging set.
    (h) NHTSA may exclude or exempt vehicles and engines under special
conditions allowed by EPA in accordance with 40 CFR parts 85, 86, 1036,
1037, and 1068. Manufacturers should consult the agencies if uncertain
how to apply any EPA provision under the NHTSA fuel consumption
program. Upon notification by EPA of a fraudulent use of an exemption,
NHTSA reserves that right to suspend or revoke any exemption or
exclusion.

Sec.  535.4  Definitions.

    The terms manufacture and manufacturer are used as defined in
section 501 of the Act and the terms commercial medium-duty and heavy-
duty on highway vehicle, fuel and work truck are used as defined in 49
U.S.C. 32901.
    Act means the Motor Vehicle Information and Cost Savings Act, as
amended by Pub. L. 94-163 and 96-425.
    Administrator means the Administrator of the National Highway
Traffic Safety Administration (NHTSA) or the Administrator's delegate.
    Advanced technology means vehicle technology under this fuel
consumption program in Sec. Sec.  535.6 and 535.7 and by EPA under 40
CFR 86.1819-14(d)(7), 1036.615, or 1037.615.
    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.
    Automatic tire inflation system has the meaning 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. 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) Vocational light-heavy vehicles with a GVWR above 8,500 pounds
but at or below 19,500 pounds.
    (3) Vocational and tractor medium-heavy vehicles with a GVWR above
19,500 pounds but at or below 33,000 pounds.
    (4) Vocational and tractor heavy-heavy vehicles with a GVWR above
33,000 pounds.
    (5) Compression-ignition light heavy-duty engines for Class 2b to 5
vehicles with a GVWR above 8,500 pounds but at or below 19,500 pounds.
    (6) Compression-ignition medium heavy-duty engines for Class 6 and
7 vehicles with a GVWR above 19,500 but at or below 33,000 pounds.
    (7) Compression-ignition heavy heavy-duty engines for Class 8
vehicles with a GVWR above 33,000 pounds.
    (8) Spark-ignition engines in Class 2b to 8 vehicles with a GVWR
above 8,500 pounds.
    (9) Long box van trailers.
    (10) Short box van trailers.
    (11) Long refrigerated box van trailers.
    (12) Short refrigerated box van trailers.
    Cab-complete vehicle has the meaning given in 49 CFR part 523.
    Carryover means relating to certification based on emission data
generated from an earlier model year.
    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 means process of obtaining a certificate of
conformity for a vehicle family that complies with the emission
standards and requirements in this part.
    Certified emission level means the highest deteriorated emission
level in an engine family for a given pollutant from the applicable
transient and/or steady-state testing rounded to the same number of
decimal places as the applicable standard. Note that you may have two
certified emission levels for CO2 if you certify a family
for both vocational and tractor use.
    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.
    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 that 40 CFR 1036.1 also deems
gas turbine engines and other engines to be compression-ignition
engines.

    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.
    Curb weight has the meaning given in 40 CFR 86.1803.
    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.
    Emergency vehicle means a vehicle that meets one of the criteria in
40 CFR 1037.801.
    Engine family has the meaning given in 40 CFR 1036.230.
    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 in 40 CFR 1037.801.
    Final-stage manufacturer has the meaning given in 49 CFR 567.3.
    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 each 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.
    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.
    Gaseous fuel has the meaning given in 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 judgment.
    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 means a Class 8 vehicle with a GVWR
above 33,000 pounds.
    Hybrid engine or hybrid powertrain means an engine or 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 that certain provisions in this part treat hybrid engines and
powertrains intended for vehicles that include regenerative braking
different than those intended for vehicles that do not include
regenerative braking.
    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.
    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.
    Light heavy-duty (LHD) vehicle means a Class 2b through 5 vehicle
with a GVWR at or below 19,500 pounds.
    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.
    Medium heavy-duty (MHD) vehicle means a Class 6 or 7 vehicle with a
GVWR above 19,500 pounds GVWR but at or below 33,000 pounds.
    Model type has the meaning given in 40 CFR 600.002.
    Model year as it applies to engines 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 standards.
    Model year as it applies to vehicles means the manufacturer's
annual new model production period, except as restricted under this
definition and 40 CFR part 85, subpart X. 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.
    (1) 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.
    (2) 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 redesignate 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.
    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.
    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.
    Petroleum has the meaning given in 40 CFR 1036.801.
    Pickup truck has the meaning given in 49 CFR part 523.
    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.
    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
involing NHTSA, EPA will ensure decisions are jointly made and will
convey the decision to the manufacturer.
    Primary intended service class has the meaning for engines as
specified in 40 CFR 1036.140.
    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 a electric hybrid vehicle.
    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 fuel consumption standards and requirements apply,
and are defined as follows:
    (1) Heavy-duty pick-up trucks and vans.
    (2) Vocational vehicle subcategories are shown in Tables 1 and 2
below and include vocational tractors. Table 1 includes vehicles
complying with Phase 1 standards. Phase 2 vehicles are included in
Table 2 which have 21 separate subcategories to account for differences
in engine type, GVWR, and the vehicle characteristics corresponding to
the duty cycles for vocational vehicles.

            Table 1--Phase 1 Vocational Vehicle Subcategories
------------------------------------------------------------------------

-------------------------------------------------------------------------
LHD vocational vehicles.
MHD vocational vehicles.
HHD vocational vehicles.
------------------------------------------------------------------------

                                Table 2--Phase 2 Vocational Vehicle Subcategories
----------------------------------------------------------------------------------------------------------------
           Engine type              LHD vocational vehicles    MHD vocational vehicles   HHD vocational vehicles
----------------------------------------------------------------------------------------------------------------
CI...............................  Urban....................  Urban...................  Urban.
CI...............................  Multi-Purpose............  Multi-Purpose...........  Multi-Purpose.
CI...............................  Regional.................  Regional................  Regional.
CI and SI........................  Emergency................  Emergency...............  Emergency.
SI...............................  Urban....................  Urban...................  Urban.
SI...............................  Multi-Purpose............  Multi-Purpose...........  Multi-Purpose.
SI...............................  Regional.................  Regional................  Regional.
----------------------------------------------------------------------------------------------------------------

    (3) Tractor subcategories are shown in Table 3 below for Phase 1
and 2. Table 3 includes 10 separate subcategories for tractors
complying with Phase 1 and 2 standards. The heavy-haul tractor
subcategory only applies for Phase 2.

           Table 3--Phase 1 and 2 Truck Tractor Subcategories
------------------------------------------------------------------------
           Class 7              Class 8 day cabs    Class 8 sleeper cabs
------------------------------------------------------------------------
Low-roof tractors...........  Low-roof day cab      Low-roof sleeper cab
                               tractors.             tractors.
Mid-roof tractors...........  Mid-roof day cab      Mid-roof sleeper cab
                               tractors.             tractors.
High-roof tractors..........  High-roof day cab     High-roof sleeper
                               tractors.             cab tractors.
                                                    Heavy-haul tractors
                                                     (applies only to
                                                     Phase 2 program).
------------------------------------------------------------------------

    (4) Trailer subcategories are shown in Table 4 of this section for
the Phase 2 program. Trailers do not comply under the Phase 1 program.
Table 4 includes 10 separate subcategories for trailers, which are only
subject to Phase 2 only standards.

                     Table 4--Trailer Subcategories
------------------------------------------------------------------------
                                  Partial-aero
     Full-aero trailers             trailers           Other trailers
------------------------------------------------------------------------
Long box dry vans...........  Long box dry vans...  Non-aero box vans.
Short box dry vans..........  Short box dry vans..  Non-box trailers.
Long box refrigerated vans..  Long box              ....................
                               refrigerated vans.
Short box refrigerated vans.  Short box             ....................
                               refrigerated vans.
------------------------------------------------------------------------

    (5) Engine subcategories are shown in Table 5 below. Table 5
includes 6 separate subcategories for engines which are the same for
Phase 1 and 2 standards.

                      Table 5--Engine Subcategories
------------------------------------------------------------------------
         LHD engines               MHD engines           HHD engines
------------------------------------------------------------------------
CI engines for vocational     CI engines for        CI engines for
 vehicles.                     vocational vehicles.  vocational
                                                     vehicles.
                              CI engines for truck  CI engines for truck
                               tractors.             tractors.
------------------------------------------------------------------------
                       All spark-ignition engines.
------------------------------------------------------------------------

    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.
    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.
    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.
    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.
    (3) For trailers:
    (i) 10 tons for short box vans.
    (ii) 19 tons for other trailers.
    Standard tractor has the meaning given in 40 CFR 1037.501.
    Standard trailer has the meaning given in 40 CFR 1037.501.
    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.
    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.
    Truck tractor has the meaning given in 49 CFR 571.3. This includes
most heavy-duty vehicles specifically designed for the primary purpose
of pulling trailers, but does not include vehicles designed to carry
other loads. For purposes of this definition ``other loads'' would not
include loads carried in the cab, sleeper compartment, or toolboxes.
Examples of vehicles that are similar to tractors but that are not
tractors under this part include dromedary tractors, automobile
haulers, straight trucks with trailers hitches, and tow trucks.
    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. 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.
    Vehicle service class has the meaning for vehicles as specified in
the 40 CFR 1037.801.
    Vocational tractor has the meaning given in 40 CFR 1037.801.
    Zero emissions vehicle means an electric vehicle or a fuel cell
vehicle.

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 useful
life. If the manufacturer's fleet includes conventional vehicles
(gasoline, diesel and alternative fueled vehicles) and advanced
technology vehicles in Phase 1 (hybrids with regenerative braking,
vehicles equipped with Rankine-cycle engines, electric and fuel cell
vehicles), it should 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).
NHTSA standards correspond to the same requirements for EPA as
specified in 40 CFR 86.1819-14.
    (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) 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.
    (2) Subconfiguration target standards. (i) Two alternatives exist
for determining the subconfiguration target standards for Phase 1. For
each alternative, separate standards exist for compression-ignition and
spark-ignition vehicles:
    (A) The first alternative allows manufacturers to determine a fixed
fuel consumption standard that is constant over the model years; and
    (B) The second alternative allows manufacturers to determine
standards that are phased-in gradually each year.
    (ii) Calculate the subconfiguration target standards as specified
in this paragraph (a)(2)(ii), using the appropriate coefficients from
Table 6 choosing between the alternatives in paragraph (a)(2)(i) of
this section. For electric or fuel cell heavy-duty vehicles, use
compression-ignition vehicle coefficients ``c'' and ``d'' and for
hybrid (including plug-in hybrid), dedicated and dual-fueled vehicles,
use coefficients ``c'' and ``d'' appropriate for the engine type used.
Round each standard to the nearest 0.001 gallons per 100 miles and
specify all weights in pounds rounded to the nearest pound. Calculate
the subconfiguration target standards using the following equation:

Subconfiguration Target Standard (gallons per 100 miles) = [c x (WF)] +
d
    Where:
WF = Work Factor = [0.75 x (Payload Capacity + Xwd)] + [0.25 x Towing
Capacity]
Xwd = 4wd Adjustment = 500 lbs if the vehicle group is equipped with
4wd and all-wheel drive, otherwise equals 0 lbs for 2wd.
Payload Capacity = GVWR (lbs) - Curb Weight (lbs) (for each vehicle
group)
Towing Capacity = GCWR (lbs) - GVWR (lbs) (for each vehicle group)

  Table 6--Coefficients for Mandatory Subconfiguration Target Standards
------------------------------------------------------------------------
           Model year(s)                    c                  d
------------------------------------------------------------------------
              Phase 1 Alternative 1--Fixed Target Standards
------------------------------------------------------------------------
                         CI Vehicle Coefficients
------------------------------------------------------------------------
2016 to 2018......................          0.0004322              3.330
2019 to 2020......................          0.0004086              3.143
------------------------------------------------------------------------
                         SI Vehicle Coefficients
------------------------------------------------------------------------
2016 to 2018......................          0.0005131              3.961
2019 to 2020......................          0.0004951              3.815
------------------------------------------------------------------------

            Phase 1 Alternative 2--Phased-in Target Standards
------------------------------------------------------------------------
                         CI Vehicle Coefficients
------------------------------------------------------------------------
2016..............................          0.0004519              3.477
2017..............................          0.0004371              3.369
2018 to 2020......................          0.0004086              3.143
------------------------------------------------------------------------
                         SI Vehicle Coefficients
------------------------------------------------------------------------
2016..............................          0.0005277              4.073
2017..............................          0.0005176              3.983
2018 to 2020......................          0.0004951              3.815
------------------------------------------------------------------------
                     Phase 2--Fixed Target Standards
------------------------------------------------------------------------
                         CI Vehicle Coefficients
------------------------------------------------------------------------
2021..............................          0.0003988              3.065
2022..............................          0.0003880              2.986
2023..............................          0.0003792              2.917
2024..............................          0.0003694              2.839
2025..............................          0.0003605              2.770
2026..............................          0.0003507              2.701
2027 and later....................          0.0003418              2.633
------------------------------------------------------------------------
                         SI Vehicle Coefficients
------------------------------------------------------------------------
2021..............................          0.0004827              3.725
2022..............................          0.0004703              3.623
2023..............................          0.0004591              3.533
2024..............................          0.0004478              3.443
2025..............................          0.0004366              3.364
2026..............................          0.0004253              3.274
2027 and later....................          0.0004152              3.196
------------------------------------------------------------------------

    (3) Fleet average fuel consumption standard. (i) Calculate each
manufacturer's fleet average fuel consumption standard for conventional
and advanced technology fleets separately based on the subconfiguration
target standards specified in paragraph (a)(2) of this section,
weighted to production volumes and averaged using the following
equation combining all the applicable vehicles in a manufacturer's
U.S.-directed fleet (compression-ignition, spark-ignition and advanced
technology vehicles) for a given model year, rounded to the nearest
0.001 gallons per 100 miles:
[GRAPHIC] [TIFF OMITTED] TP13JY15.108

Where:

Subconfiguration Target Standardi = fuel consumption
standard for each group of vehicles with same payload, towing
capacity and drive configuration (gallons per 100 miles).
Volumei = production volume of each unique subconfiguration of a
model type based upon payload, towing capacity and drive
configuration.

    (A) A manufacturer may group together subconfigurations that have
the same test weight (ETW), GVWR, and GCWR. Calculate work factor and
target value assuming a curb weight equal to two times ETW minus GVWR.
    (B) A manufacturer may group together other subconfigurations if it
uses the lowest target value calculated for any of the
subconfigurations.
    (ii) For Phase 1, manufacturers must select an alternative for
subconfiguration target standards at the same time they submit the
model year 2016 pre-model year Report, specified in Sec.  535.8. Once
selected, the decision cannot be reversed and the manufacturer must
continue to comply with the same alternative for subsequent model
years.
    (4) Voluntary standards. (i) Manufacturers may choose voluntarily
to comply early with fuel consumption standards for model years 2013
through 2015, as determined in paragraphs (a)(4)(iii) and (iv) of this
section, for example, in order to begin accumulating credits through
over-compliance with the applicable standard. A manufacturer choosing
early compliance must comply with all the vehicles and engines it
manufactures in each regulatory category for a given model year.
    (ii) A manufacturer must declare its intent to voluntarily comply
with fuel consumption standards at the same time it submits a Pre-Model
Report, prior to the compliance model year beginning as specified in
Sec.  535.8; and, once selected, the decision cannot be reversed and
the manufacturer must continue to comply for each subsequent model year
for all the vehicles and engines it

manufactures in each regulatory category for a given model year.
    (iii) Calculate separate subconfiguration target standards for
compression-ignition and spark-ignition vehicles for model years 2013
through 2015 using the equation in paragraph (a)(2)(ii) of this
section, substituting the appropriate values for the coefficients in
the following table as appropriate:

  Table 7--Coefficients for Voluntary Subconfiguration Target Standards
------------------------------------------------------------------------
           Model year(s)                    c                  d
------------------------------------------------------------------------
                         CI Vehicle Coefficients
------------------------------------------------------------------------
2013 and 14.......................          0.0004695              3.615
2015..............................          0.0004656              3.595
------------------------------------------------------------------------
                         SI Vehicle Coefficients
------------------------------------------------------------------------
2013 and 14.......................          0.0005424              4.175
2015..............................          0.0005390              4.152
------------------------------------------------------------------------

    (iv) Calculate the fleet average fuel consumption standards for
model years 2013 through 2015 using the equation in paragraph (a)(3) of
this section.
    (5) Exclusion of vehicles not certified as complete vehicles. The
vehicle standards in paragraph (a) of this section do not apply for
vehicles that are chassis-certified with respect to EPA's criteria
pollutant test procedure in 40 CFR part 86, subpart S. Any chassis-
certified vehicles must comply with the vehicle standards and
requirements of paragraph (b) of this section and the engine standards
of paragraph (d) of this section for engines used in these vehicles. A
vehicle manufacturer choosing to comply with this paragraph and that is
not the engine manufacturer is required to notify the engine
manufacturers that their engines are subject to paragraph (d) of this
section and that it intends to use their engines in excluded vehicles.
    (6) Optional certification under this section. Manufacturers may
certify any complete or cab-complete Class 2b through 5 vehicles
weighing at or below 19,500 pounds GVWR and any incomplete vehicles
approved by EPA for inclusion under this paragraph to the same testing
and standard that applies to a comparable complete sister vehicles as
determined in accordance in 40 CFR 86.1819-14(j). Calculate the target
standard value under paragraph (a)(2) of this section based on the same
work factor value that applies for the complete sister vehicle.
    (7) Loose engines. This paragraph applies for model year 2020 and
earlier spark-ignition engines identical to engines used in vehicles
certified to the standards of this paragraph (a), where manufacturers
sell such engines as loose engines or installed in incomplete vehicles
that are not cab-complete vehicles in accordance with 40 CFR 86.1819-
14(k)(8). Vehicles in which those engines are installed are subject to
standards in paragraph (b) of this section and the engines are subject
to standards in paragraph (d) of this section. Loose engines produced
each model year must comply with provisions of 40 CFR 86.1819-14(k)(8).
    (8) Alternative fuel vehicle conversions. Alternative fuel vehicle
conversions may demonstrate compliance with the standards of this part
or other alternative compliance approaches allowed by EPA in 40 CFR
85.525.
    (9) Useful life. The following useful life values apply for the
standards of this section:
    (i) 120,000 miles or 10 years, whichever comes first, for Class 2b
through Class 3 heavy-duty pickup trucks and vans certified to Phase 1
standards.
    (ii) 150,000 miles or 15 years, whichever comes first, for Class 2b
through Class 3 heavy-duty pickup trucks and vans certified to Phase 2
standards.
    (iii) For Phase 1 credits that you calculate based on a useful life
of 120,000 miles, multiply any banked credits that you carry forward
for use into the Phase 2 program by 1.25. For Phase 1 credit deficits
that you generate based on a useful life of 120,000 miles multiply the
credit deficit by 1.25 if offsetting the shortfall with Phase 2
credits.
    (10) Optional standards. For model years 2013 through 2019,
manufacturers may calculate target standards ``c'' coefficients rounded
to the nearest six decimal places (0.000001) and ``d'' coefficients
rounded to the nearest two decimal places (0.01) based on the standards
listed in tables 6 or 7. If a manufacturer chooses this option, the
fleet standard calculated in accordance with paragraph (a)(3) of this
section and fuel consumption rate calculated in accordance with
paragraph (a)(5) of this section must be rounded to the nearest 0.01
gallons per 100 miles. If a manufacturer chooses this provision it will
be applicable for all model years 2013 through 2019.
    (b) Heavy-duty vocational vehicles. Each manufacturer building a
complete or incomplete heavy-duty vocational vehicles shall comply with
the fuel consumption standards in this paragraph (b) expressed in
gallons per 1000 ton-miles. 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 useful
life.
    (1) Mandatory standards. Heavy-duty vocational vehicles produced
for Phase 1 must comply with the fuel consumption standards in
paragraph (b)(3) of this section. For Phase 2, each vehicle
manufacturer of heavy-duty vocational vehicles must comply with the
fuel consumption standards in paragraph (b)(4) of this section.
    (i) For model years 2016 to 2020, the heavy-duty vocational
vehicles are subdivided by GVWR into three regulatory subcategories as
defined in Sec.  535.4, each with its own assigned standard.
    (ii) For model years 2021 and later, the heavy-duty vocational
vehicle category is subdivided into 21 regulatory subcategories
depending upon whether vehicles are equipped with a compression or
spark ignition engine, as defined in Sec.  535.4. Each subcategory has
its own assigned standard.
    (iii) For purposes of certifying vehicles to fuel consumption
standards, manufacturers must divide their product lines in each
regulatory subcategory into vehicle families that have similar
emissions and fuel consumption features, as specified by EPA in 40 CFR
part 1037, subpart C. These families will be subject to the

applicable standards. Each vehicle family is limited to a single model
year.
    (2) Voluntary compliance. (i) For model years 2013 through 2015, a
manufacturer may choose voluntarily to comply early with the fuel
consumption standards provided in paragraph (b)(3) of this section. For
example, a manufacturer may choose to comply early in order to begin
accumulating credits through over-compliance with the applicable
standards. A manufacturer choosing early compliance must comply with
all the vehicles and engines it manufacturers in each regulatory
category for a given model year.
    (ii) A manufacturer must declare its intent to voluntarily comply
with fuel consumption standards and identify its plans to comply before
it submits its first application for a certificate of conformity for
the respective model year as specified in Sec.  535.8; and, once
selected, the decision cannot be reversed and the manufacturer must
continue to comply for each subsequent model year for all the vehicles
and engines it manufacturers in each regulatory category for a given
model year.
    (3) Regulatory subcategory standards for model years 2013 to 2020.
The mandatory and voluntary fuel consumption standards for heavy-duty
vocational vehicles are given in the following table:

                         Table 8--Phase 1 Vocational Vehicle Fuel Consumption Standards
                                          [Gallons per 1000 ton-miles]
----------------------------------------------------------------------------------------------------------------
                                                                  LHD Vocational  MHD Vocational  HHD Vocational
                    Regulatory subcategories                         vehicles        vehicles        vehicles
----------------------------------------------------------------------------------------------------------------
                                  Model Years 2013 to 2016 Voluntary Standards
----------------------------------------------------------------------------------------------------------------
Standard........................................................         38.1139         22.9862         22.2004
----------------------------------------------------------------------------------------------------------------
                                  Model Years 2017 to 2020 Mandatory Standards
----------------------------------------------------------------------------------------------------------------
Standard........................................................         36.6405         22.1022         21.8075
----------------------------------------------------------------------------------------------------------------

    (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--Phase 2 Vocational Vehicle Fuel Consumption Standards
                                          [gallons per 1000 ton-miles]
----------------------------------------------------------------------------------------------------------------
                                                                  LHD Vocational  MHD Vocational  HHD Vocational
                           Duty cycle                                vehicles        vehicles        vehicles
----------------------------------------------------------------------------------------------------------------
                               Model Years 2021 to 2023 Standards for CI Vehicles
----------------------------------------------------------------------------------------------------------------
Urban...........................................................         29.0766         18.4676         19.4499
Multi-Purpose...................................................         29.9607         18.6640         19.6464
Regional........................................................         31.2377         18.2711         18.5658
----------------------------------------------------------------------------------------------------------------
                               Model Years 2021 to 2023 Standards for SI Vehicles
----------------------------------------------------------------------------------------------------------------
Urban...........................................................         36.0077         22.8424         24.0801
Multi-Purpose...................................................         37.0204         23.0674         24.3052
Regional........................................................         38.5957         22.6173         22.9549
----------------------------------------------------------------------------------------------------------------
                               Model Years 2024 to 2026 Standards for CI Vehicles
----------------------------------------------------------------------------------------------------------------
Urban...........................................................         27.8978         17.5835         18.6640
Multi-Purpose...................................................         28.6837         17.7800         18.8605
Regional........................................................         29.8625         17.4853         17.8782
----------------------------------------------------------------------------------------------------------------
                               Model Years 2024 to 2026 Standards for SI Vehicles
----------------------------------------------------------------------------------------------------------------
Urban...........................................................         35.1075         22.1672         23.4050
Multi-Purpose...................................................         36.1202         22.3923         23.6300
Regional........................................................         37.5830         22.0547         22.3923
----------------------------------------------------------------------------------------------------------------
                              Model Years 2027 and later Standards for CI Vehicles
----------------------------------------------------------------------------------------------------------------
Urban...........................................................         26.7191         16.8959         17.8782
Multi-Purpose...................................................         27.5049         17.0923         17.9764
Regional........................................................         28.6837         16.6994         17.0923
----------------------------------------------------------------------------------------------------------------
                              Model Years 2027 and later Standards for SI Vehicles
----------------------------------------------------------------------------------------------------------------
Urban...........................................................         33.6446         21.2670         22.0547
Multi-Purpose...................................................         34.6574         21.4921         22.2797

Regional........................................................         36.1202         21.0420         21.1545
----------------------------------------------------------------------------------------------------------------

    (5) Regulatory subcategory standards for model year 2021 and later
emergency vehicles. The mandatory fuel consumption standards for heavy-
duty emergency vehicles are given in the following table:

                         Table 10--Phase 2 Emergency Vehicle Fuel Consumption Standards
                                         [Gallons per 1000 ton-miles] *
----------------------------------------------------------------------------------------------------------------
                                                                LHD Vocational   MHD Vocational   HHD Vocational
                   Regulatory subcategories                        vehicles         vehicles         vehicles
----------------------------------------------------------------------------------------------------------------
Model Years 2021 and later Emergency Vehicle Standards.......         30.6483          19.1552          21.1198
----------------------------------------------------------------------------------------------------------------
* Vehicles certified to these alternative standards may not generate fuel consumption credits.

    (6) Subfamily standards. Manufacturers may specify a family
emission limit (FEL) in terms of fuel consumption for each vehicle
subfamily. The FEL may not be less than the result of fuel consumption
modeling from 40 CFR 1037.520. The FELs is the fuel consumption
standards for the vehicle subfamily instead of the standards specified
in paragraph (b)(3) and (4) of this section and can be used for
calculating fuel consumption credits in accordance with Sec.  535.7.
    (7) Vehicle families for advanced and innovative technologies. For
vocational vehicles subject to Phase 1 standards, manufacturers must
create separate vehicle families for vehicles that contain advanced or
off-cycle technologies and group those vehicles together in a vehicle
family if they use the same advanced or innovative technologies.
    (8) Certifying across service classes. A manufacturer may
optionally certify a vocational vehicle to the standards and useful
life applicable to a heavier vehicle service class (or regulatory
subcategory changes such as complying with the heavy heavy-duty
standard instead of medium heavy-duty standard), provided the
manufacturer does not generate credits with the vehicle. If a
manufacturer includes lighter vehicles in a credit-generating subfamily
(with an FEL below the standard), they must exclude their production
volume from the credit calculation. Note that if the subfamily is a
credit-using subfamily, the manufacturer must include the production
volume of the lighter vehicles in the credit calculations.
    (9) Off-road exemptions. Heavy-duty vocational vehicles, including
vocational tractors meeting the off-road criteria in Sec.  535.3 are
exempted from the requirements in this paragraph (b) of this section,
but the engines in these vehicles must meet the requirements of
paragraph (d) of this section. Manufacturers may request approval in
accordance with the provisions in 40 CFR 1037.150 and 40 CFR 1037.210
to determine if they are producing vehicles that meet the criteria for
the heavy-duty off-road vehicle exemption. A manufacturer's request
must be submitted in advance of the model year, or early enough in the
model year, to ensure that an application for a certificate of
conformity, as required in 40 CFR 1037.201, can be submitted if the
approval is denied. The approval is a collaboration between NHTSA and
EPA and can be given informally or through a formal determination. If a
manufacturer requests a formal determination, the manufacturer must
submit the required documentation in 40 CFR 1037.150 to both agenices.
    (10) Small business alternative fuel engine converters. Small
business alternative fuel engine converters may delay implementation of
the standards in paragraph (b)(4) of this section for one year for each
increase in stringency throughout the proposed rule.
    (11) Useful life. The following useful life values apply for the
standards of this section:
    (i) 110,000 miles or 10 years, whichever comes first, for Class 2b
through Class 5 vocational vehicles certified to Phase 1 standards.
    (ii) 150,000 miles or 15 years, whichever comes first, for Class 2b
through Class 5 vocational vehicles certified to Phase 2 standards.
    (iii) 185,000 miles or 10 years, whichever comes first, for Class 6
and Class 7 vehicles above 19,500 pounds GVWR and at or below 33,000
pounds GVWR for Phase 1 and for Phase 2.
    (iv) 435,000 miles or 10 years, whichever comes first, for Class 8
vehicles above 33,000 pounds GVWR for Phase 1 and for Phase 2.
    (v) For Phase 1 credits that you calculate based on a useful life
of 110,000 miles, multiply any banked credits that you carry forward
for use into the Phase 2 program by 1.36. For Phase 1 credit deficits
that you generate based on a useful life of 110,000 miles multiply the
credit deficit by 1.36, if offsetting the shortfall with Phase 2
credits.
    (12) Recreational vehicles. Recreational vehicles manufactured
after model year 2020 must comply with the fuel consumption standards
of this section. Manufacturers producing these vehicles may also
certify to fuel consumption standards from 2014 through model year
2020. Manufacturers may earn credits retroactively for early compliance
with fuel consumption standards. Once selected, a manufacturer cannot
reverse the decision and the manufacturer must continue to comply for
each subsequent model year for all the vehicles it manufacturers in
each regulatory subcategory for a given model year.
    (13) Optional standards. (i) For model years 2013 through 2019,
manufacturers have the option to use heavy-duty vocational vehicle fuel
consumption standards given in the following table:

                        Table 11--Optional Vocational Vehicle Fuel Consumption Standards
                                          [Gallons per 1,000 ton-miles]
----------------------------------------------------------------------------------------------------------------
                    Regulatory subcategories                        LH vehicles     MH vehicles     HH vehicles
----------------------------------------------------------------------------------------------------------------
                                  Model Years 2017 to 2019 Mandatory Standards
----------------------------------------------------------------------------------------------------------------
Standard........................................................            36.7            22.1            21.8
----------------------------------------------------------------------------------------------------------------
                                       Model Year 2016 Mandatory Standard
----------------------------------------------------------------------------------------------------------------
Standard........................................................            38.1            23.0            22.2
----------------------------------------------------------------------------------------------------------------
                                  Model Years 2013 to 2015 Voluntary Standards
----------------------------------------------------------------------------------------------------------------
Standard........................................................            38.1            23.0            22.2
----------------------------------------------------------------------------------------------------------------

    (ii) If a manufacturer chooses this option, the fuel consumption
rate calculated in accordance with 49 CFR 535.6(b)(4) must be rounded
to the nearest 0.1 gallons per 1,000 ton-miles.
    (iii) If a manufacturer chooses this option, it must apply these
same standards for each model year from 2013 through 2019.
    (c) Truck tractors. Each manufacturer building truck tractors,
except vocational tractors, with a GVWR above 26,000 pounds shall
comply with the fuel consumption standards in this paragraph (c)
expressed in gallons per 1000 ton-miles. Each vehicle must be
manufactured to comply for its useful life.
    (1) Mandatory standards. For model years 2016 and later, each
manufacturer of truck tractors must comply with the fuel consumption
standards in paragraph (c)(3) of this section.
    (i) Based on the roof height and the design of the cab, truck
tractors are divided into subcatagories as described in Sec.  535.4.
The standards that apply to each regulatory subcategory are shown in
paragraphs (c)(2) and (3) of this section, each with its own assigned
standard.
    (ii) For purposes of certifying vehicles to fuel consumption
standards, manufacturers must divide their product lines in each
regulatory subcategory into vehicles families that have similar
emissions and fuel consumption features, as specified by EPA in 40 CFR
1037.230, and these families will be subject to the applicable
standards. Each vehicle family is limited to a single model year.
    (iii) Standards for truck tractor engines are given in paragraph
(d) of this section.
    (2) Voluntary compliance. (i) For model years 2013 through 2015, a
manufacturer may choose voluntarily to comply early with the fuel
consumption standards provided in paragraph (c)(3) of this section. For
example, a manufacturer may choose to comply early in order to begin
accumulating credits through over-compliance with the applicable
standards. A manufacturer choosing early compliance must comply with
all the vehicles and engines it manufacturers in each regulatory
category for a given model year.
    (ii) A manufacturer must declare its intent to voluntarily comply
with fuel consumption standards and identify its plans to comply before
it submits its first application for a certificate of conformity for
the respective model year as specified in Sec.  535.8; and, once
selected, the decision cannot be reversed and the manufacturer must
continue to comply for each subsequent model year for all the vehicles
and engines it manufacturers in each regulatory category for a given
model year.
    (3) Regulatory subcategory standards. The fuel consumption
standards for truck tractors, except for vocational tractors, are given
in the following table:

                               Table 12--Truck Tractor Fuel Consumption Standards
                                          [Gallons per 1,000 ton-miles]
----------------------------------------------------------------------------------------------------------------
                                                              Day cab               Sleeper cab
            Regulatory subcategories             ------------------------------------------------   Heavy-haul
                                                      Class 7         Class 8         Class 8
----------------------------------------------------------------------------------------------------------------
                              Phase 1--Model Years 2013 to 2015 Voluntary Standards
----------------------------------------------------------------------------------------------------------------
Low Roof........................................         10.5108          7.9568          6.6798  ..............
Mid Roof........................................         11.6896          8.6444          7.4656  ..............
High Roof.......................................         12.1807          9.0373          7.3674  ..............
----------------------------------------------------------------------------------------------------------------
                                   Phase 1--Model Year 2016 Mandatory Standard
----------------------------------------------------------------------------------------------------------------
Low Roof........................................         10.5108          7.9568          6.6798  ..............
Mid Roof........................................         11.6896          8.6444          7.4656  ..............
High Roof.......................................         12.1807          9.0373          7.3674  ..............
----------------------------------------------------------------------------------------------------------------
                              Phase 1--Model Years 2017 to 2020 Mandatory Standards
----------------------------------------------------------------------------------------------------------------
Low Roof........................................         10.2161          7.8585          6.4833  ..............
Mid Roof........................................         11.2967          8.4479          7.1709  ..............
High Roof.......................................         11.7878          8.7426          7.0727  ..............
----------------------------------------------------------------------------------------------------------------

                              Phase 2--Model Years 2021 to 2023 Mandatory Standards
----------------------------------------------------------------------------------------------------------------
Low Roof........................................          9.5285          7.6621          6.8762          5.3045
Mid Roof........................................         10.5108          8.2515          7.6621  ..............
High Roof.......................................         10.7073          8.4479          7.5639  ..............
----------------------------------------------------------------------------------------------------------------
                              Phase 2--Model Years 2024 to 2026 Mandatory Standards
----------------------------------------------------------------------------------------------------------------
Low Roof........................................          8.8409          7.0727          6.2868          5.1081
Mid Roof........................................          9.8232          7.6621          6.9745  ..............
High Roof.......................................          9.9214          7.7603          6.8762  ..............
----------------------------------------------------------------------------------------------------------------
                             Phase 2--Model Years 2027 and later Mandatory Standards
----------------------------------------------------------------------------------------------------------------
Low Roof........................................          8.5462          6.8762          6.0904          5.0098
Mid Roof........................................          9.4303          7.4656          6.7780  ..............
High Roof.......................................          9.4303          7.4656          6.5815  ..............
----------------------------------------------------------------------------------------------------------------

    (4) Subfamily standards. Manufacturers may specify a family
emission limit (FEL) in terms of fuel consumption for each vehicle
subfamily. The FEL may not be less than the result of fuel consumption
modeling from 40 CFR 1037.520. The FEL serves as the fuel consumption
standards for the vehicle subfamily instead of the standards specified
in paragraph (c)(3) of this section and can be used for calculating
fuel consumption credits in accordance with Sec.  535.7.
    (5) Vehicle families for advanced and innovative technologies. For
tractors subject to Phase 1 standards, manufacturers must create
separate vehicle families for vehicles that contain advanced or off-
cycle technologies and group those vehicles together in a vehicle
family if they use the same advanced or innovative technologies.
    (6) Certifying across service classes. A manufacturer may
optionally certify a tractor to the standards and useful life
applicable to a heavier vehicle service class (or regulatory
subcategory changes such as complying with the Class 8 day-cab tractor
standard instead of Class 7 day-cab tractor), provided the manufacturer
does not generate credits with the vehicle. If a manufacturer includes
lighter vehicles in a credit-generating subfamily (with an FEL below
the standard), exclude their production volume from the credit
calculation. Note that if the subfamily is a credit-using subfamily,
the manufacturer must include the production volume of the lighter
vehicles in the credit calculations.
    (7) Vocational tractors. Tractors meeting the definition of
vocational tractors in 49 CFR 523.2 must comply with requirements for
heavy-duty vocational vehicles specified in paragraphs (b) and (d) of
this section. Class 7 and Class 8 tractors certified or exempted as
vocational tractors are limited in production to no more than 21,000
vehicles in any three consecutive model years. If a manufacturer is
determined as not applying this allowance in good faith by EPA in its
applications for certification in accordance with 40 CFR 1037.205 and
1037.610, a manufacturer must comply with the tractor fuel consumption
standards in paragraph (c)(3) of this section.
    (8) Optional standards. (i) For Phase 1, manufacturers may use the
heavy-duty truck tractor fuel consumption standards given in the
following table:

         Table 13-- Optional Truck Tractor Fuel Consumption Standards for Model Years 2013 Through 2019
                                          [Gallons per 1,000 ton-miles]
----------------------------------------------------------------------------------------------------------------
                                                                             Day cab                Sleeper cab
                    Regulatory subcategories                    ------------------------------------------------
                                                                     Class 7         Class 8          Class 8
----------------------------------------------------------------------------------------------------------------
                                  Model Years 2017 to 2019 Mandatory Standards
----------------------------------------------------------------------------------------------------------------
Low Roof.......................................................            10.2              7.8             6.5
Mid Roof.......................................................            11.3              8.4             7.2
High Roof......................................................            11.8              8.7             7.1
----------------------------------------------------------------------------------------------------------------
                                      Model Years 2016 Mandatory Standards
----------------------------------------------------------------------------------------------------------------
Low Roof.......................................................            10.5              8               6.7
Mid Roof.......................................................            11.7              8.7             7.4
High Roof......................................................            12.2              9               7.3
----------------------------------------------------------------------------------------------------------------
                                  Model Years 2013 to 2015 Voluntary Standards
----------------------------------------------------------------------------------------------------------------
Low Roof.......................................................            10.5              8               6.7
Mid Roof.......................................................            11.7              8.7             7.4

High Roof......................................................            12.2              9               7.3
----------------------------------------------------------------------------------------------------------------

    (ii) If a manufacturer chooses this option, the fuel consumption
rate calculated in accordance with Sec.  535.6(b)(4) must be rounded to
the nearest 0.1 gallons per 1,000 ton-miles.
    (iii) If a manufacturer chooses this option, it must apply these
same standards for each model year from 2013 through 2019.
    (9) Useful life. The following useful life values apply for the
standards of this section:
    (i) 185,000 miles or 10 years, whichever comes first, for Class 6
and Class 7 tractors above 19,500 pounds GVWR and at or below 33,000
pounds GVWR for Phase 1 and for Phase 2.
    (ii) 435,000 miles or 10 years, whichever comes first, for Class 8
tractors above 33,000 pounds GVWR for Phase 1 and for Phase 2.
    (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. Each
engine must be manufactured to comply for its useful life. The
provisions of this part apply to all new 2014 model year and later
heavy-duty engines. This includes engines fueled by conventional and
alternative fuels for engines that will be installed in heavy-duty
vehicles above 14,000 pounds GVWR. These provisions also apply for
engines that will be installed in heavy-duty glider vehicles at or
below 14,000 pounds GVWR Each engine manufactured for use in a heavy-
duty tractor or vocational vehicle must be certified to the primary
intended service class that it is designed for in accordance with 40
CFR 1036.108 and 1036.140.
    (1) Mandatory standards. Manufacturers of heavy-duty engines shall
comply with the mandatory fuel consumption standards in paragraphs
(d)(3) through (6) of this section for model years 2017 and later for
compression-ignition engines and for model years 2016 and later for
spark-ignition engines.
    (i) The heavy-duty engine regulatory category is divided into six
regulatory subcategories, five compression-ignition subcategories and
one spark-ignition subcategory, as shown in Table 14 of this section.
    (ii) Separate standards exist for engines manufactured for use in
heavy-duty vocational vehicles and in truck tractors.
    (iii) For purposes of certifying engines to fuel consumption
standards, manufacturers must divide their product lines in each
regulatory subcategory into engine families that have similar fuel
consumption features and the same primary intended service class, as
specified by EPA in 40 CFR 1036.230, and these families will be subject
to the same standards. Each engine family is limited to a single model
year.
    (2) Voluntary compliance. (i) For model years 2013 through 2016 for
compression-ignition engines, and for model year 2015 for spark-
ignition engines, a manufacturer may choose voluntarily to comply with
the fuel consumption standards provided in paragraph (d)(3) through (5)
of this section. For example, a manufacturer may choose to comply early
in order to begin accumulating credits through over-compliance with the
applicable standards. A manufacturer choosing early compliance must
comply with all the vehicles and engines it manufacturers in each
regulatory category for a given model year except in model year 2013
the manufacturer may comply with individual engine families as
specified in 40 CFR 1036.150(a)(2).
    (ii) A manufacturer must declare its intent to voluntarily comply
with fuel consumption standards and identify its plans to comply before
it submits its first application for a certificate of conformity for
the respective model year as specified in Sec.  535.8; and, once
selected, the decision cannot be reversed and the manufacturer must
continue to comply for each subsequent model year for all the vehicles
and engines it manufacturers in each regulatory category for a given
model year.
    (3) Regulatory subcategory standards. The primary fuel consumption
standards for heavy-duty engines are given in the following table:

                                             Table 14--Primary Heavy-Duty Engine Fuel Consumption Standards
                                                                 [Gallons per 100 hp-hr]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                 Regulatory subcategory                   LHD CI engines   MHD CI engines and all other    HHD CI engines and all other     SI engines
---------------------------------------------------------  and all other              engines                         engines            ---------------
                                                              engines    ----------------------------------------------------------------
                       Application                       ----------------                                                                       All
                                                            Vocational      Vocational        Tractor       Vocational        Tractor
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Phase 1--Voluntary Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
2015....................................................  ..............  ..............  ..............  ..............  ..............          7.0552
2013 to 2016............................................          5.8939          5.8939          4.9312          5.5697           4.666  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Phase 1--Mandatory Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
2016....................................................  ..............  ..............  ..............  ..............  ..............          7.0552
2017 to 2020............................................          5.6582          5.6582          4.7839          5.4519          4.5187          7.0552
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                              Phase 2--Mandatory Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
2021 to 2023............................................          5.5501          5.5501          4.7053          5.3438          4.4499          7.0552
2024 to 2026............................................          5.4617          5.4617          4.6071          5.2652          4.3517          7.0552
2027 and later..........................................          5.4322          5.4322          4.5776          5.2358          4.3320          7.0552
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (4) Alternate subcategory standards. The alternative fuel
consumption standards for heavy-duty compression-ignition engines are
as follows:
    (i) Manufacturers entering the voluntary program in model years
2014 through 2016, may choose to certify compression-ignition engine
families unable to meet standards provided in paragraph (d)(3) of this
section to the alternative fuel consumption standards of this paragraph
(d)(4).
    (ii) Manufacturers may not certify engines to these alternate
standards if they are part of an averaging set in which they carry a
balance of banked credits. For purposes of this section, manufacturers
are deemed to carry credits in an averaging set if they carry credits
from advance technology that are allowed to be used in that averaging
set in accordance with Sec.  535.7(d)(12).
    (iii) The emission standards of this section are determined as
specified by EPA in 40 CFR 1036.620(a) through (c) and should be
converted to equivalent fuel consumption values.
    (5) Alternate phase-in standards. Manufacturers have the option to
comply with EPA emissions standards for compression-ignition engines
using an alternative phase-in schedule that correlates with EPA's OBD
standards. If a manufacturer chooses to use the alternative phase-in
schedule for meeting EPA standards and optionally chooses to comply
early with the NHTSA fuel consumption program, it must use the same
phase-in schedule beginning in model year 2013 for fuel consumption
standards and must remain in the program for each model year thereafter
until model year 2020. The fuel consumption standard for each model
year of the alternative phase-in schedule is provided in Table 15 of
this section. Note that engines certified to these standards are not
eligible for early credits under Sec.  535.7.

                   Table 15--Phase 1 Alternative Phase-in CI Engine Fuel Consumption Standards
                                             [Gallons per 100 hp-hr]
----------------------------------------------------------------------------------------------------------------
                            Tractors                                LHD engines     MHD engines     HHD engines
----------------------------------------------------------------------------------------------------------------
Model Years 2013 to 2015........................................              NA          5.0295          4.7642
Model Years 2016 to 2020 [dagger]...............................              NA          4.7839          4.5187
----------------------------------------------------------------------------------------------------------------
Vocational                                                          LHD engines     MHD engines     HHD engines
----------------------------------------------------------------------------------------------------------------
Model Years 2013 to 2015........................................          6.0707          6.0707          5.6680
Model Years 2016 to 2020[dagger]................................          5.6582          5.6582          5.4519
----------------------------------------------------------------------------------------------------------------
Note: [dagger] These alternate standards for 2016 and later are the same as the otherwise applicable standards
  through 2020.

    (6) Optional standards. (i) For model years 2013 through 2020,
manufacturers may use heavy-duty engine fuel consumption standards
given in the following tables:

                                         Table 16--Optional Primary Heavy-Duty Engine Fuel Consumption Standards
                                                                 [Gallons per 100 hp-hr]
--------------------------------------------------------------------------------------------------------------------------------------------------------
           Regulatory subcategory              LHD CI engines             MHD CI engines                      HHD CI engines               SI Engines
--------------------------------------------------------------------------------------------------------------------------------------------------------
                 Application                     Vocational        Vocational          Tractor         Vocational          Tractor             All
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Mandatory Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
Model Years.................................                                        2017 to 2020                                            2016 to 2019
--------------------------------------------------------------------------------------------------------------------------------------------------------
Standards...................................              5.66              5.66              4.78              5.45              4.52              7.06
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Voluntary Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
Model Years.................................                                        2013 to 2016                                                    2015
--------------------------------------------------------------------------------------------------------------------------------------------------------
Standards...................................              5.89              5.89              4.93              5.57              4.67              7.06
--------------------------------------------------------------------------------------------------------------------------------------------------------

                       Table 17--Alternative Phase-in CI Engine Fuel Consumption Standards
                                             [Gallons per 100 hp-hr]
----------------------------------------------------------------------------------------------------------------
            Truck Tractors                  LHD CI engines           MHD CI engines           HHD CI engines
----------------------------------------------------------------------------------------------------------------
Model Years 2013 to 2015.............  NA.....................  5.03...................  4.76
Model Years 2016 to 2020 [dagger]....  NA.....................  4.78...................  4.52
Vocational vehicles..................  LHD CI Engines.........  MHD CI Engines.........  HHD CI Engines
Model Years 2013 to 2015.............  6.07...................  6.07...................  5.67
Model Years 2016 and later [dagger]..  5.66...................  5.66...................  5.45
----------------------------------------------------------------------------------------------------------------

    (ii) If a manufacturer chooses this option, the fuel consumption
rate calculated in accordance with Sec.  535.6(c)(4) must be rounded to
the nearest 0.01 gallon per 100 hp-hr.
    (iii) If a manufacturer chooses this option, it must apply these
same standards for each model year from 2013 through 2020.
    (7) Specialty vehicles. Manufacturers of specialty vehicles as
identified in 40 CFR 1037.605 may comply with fuel consumption
standards by complying with alternate emission standards that are
equivalent to standards that apply for non-road engines as identified
in 40 CFR 1037.605, and using Sec.  535.6 and exercising good
engineering judgment to determine equivalent fuel consumption
standards.
    (8) Alternative fuel conversions. Engines that have been converted
to operate on alternative fuels may demonstrate compliance with the
standards of this part or other alternative compliance approaches
allowed by EPA in 40 CFR 85.525.
    (9) Useful life. The following useful life values apply for the
standards of this section:
    (i) 110,000 miles or 10 years, whichever comes first, for engines
used in Class 2b through Class 5 vehicles certified to Phase 1
standards.
    (ii) 150,000 miles or 15 years, whichever comes first, for engines
used in Class 2b through Class 5 vehicles certified to Phase 2
standards.
    (iii) 185,000 miles or 10 years, whichever comes first, for engines
used in Class 6 and Class 7 vehicles above 19,500 pounds GVWR and at or
below 33,000 pounds GVWR for Phase 1 and for Phase 2.
    (iv) 435,000 miles or 10 years, whichever comes first, for engines
used in Class 8 vehicles above 33,000 pounds GVWR for Phase 1 and for
Phase 2.
    (v) For Phase 1 credits that you calculate based on a useful life
of 110,000 miles, multiply any banked credits that you carry forward
for use into the Phase 2 program by 1.36. For Phase 1 credit deficits
that you generate based on a useful life of 110,000 miles multiply the
credit deficit by 1.36, if offsetting the shortfall with Phase 2
credits.
    (e) Heavy-duty Trailers. Each manufacturer of heavy-duty trailers
as specified in 49 CFR 523.10, shall comply with the fuel consumption
standards in paragraph (e)(1) of this section expressed in gallons per
1000 ton-miles. Each vehicle must be manufactured to comply for its
useful life. There are no Phase 1 standards for trailers. Different
levels of stringency apply for box vans depending on features that may
affect aerodynamic performance.
    (1) Fuel consumption standards. Trailers manufactured in model year
2021 and later must comply with the fuel consumption standards of this
section. For model years 2018 through 2020, trailer manufacturers have
the option to voluntarily comply with the fuel consumption standards of
this section.
    (i) Non-aero and non-box trailer standards. Non-aero and non-box
trailers must comply with the regulatory subcategory fuel consumption
standards in this section.
    (A) ``Non-aero trailers'' for trailers 35 feet or longer are box
vans that have a rear lift gate or rear hinged ramp, and at least one
of the following side features: Side lift gate, belly box, side-mounted
pull-out platform, steps for side-door access, or a drop-deck design.
``Non-aero trailers'' for trailers less than 35 feet long are
refrigerated box vans with at least one of the side features identified
for longer trailers.
    (B) Non-box trailers and non-aero trailers must meet the following
standards:
    (1) Trailers must use qualified automatic tire inflation systems
with all load-bearing wheels.
    (2) Trailers must use tires with a TRRL at or below 4.7 kg/ton.
Through model year 2023, trailers may instead use tires with a TRRL at
or below 5.1 kg/ton.
    (ii) Partial-aero trailer standards. Partial-aero trailers must
comply with the regulatory subcategory fuel consumption standards as
follows:
    (A) ``Partial-aero trailers'' are box vans that have at least one
of the side features identified in paragraph (e)(1)(i)(A) of this
section. Long box vans also qualify as partial-aero trailers if they
have a rear lift gate or rear hinged ramp.
    (B) Partial-aero trailers may continue to meet the 2024 standards
in 2027 and later model years. This provision does not apply for short
refrigerated vans because their standard does not change in 2027.
    (iii) Full-aero trailers. Full-aero trailers comply with the
regulatory subcategory fuel consumption standards as follows:
    (A) ``Full-aero trailers'' are box vans that do not meet the
specifications for non-areo or partial-aero trailers in paragraph
(e)(1)(i)(A) or (e)(1)(ii)(A) of this section.
    (B) Fuel consumption standards apply for full-aero trailers as
specified in the following table:

                         Table 18--Phase 2 Fuel Aero Trailer Fuel Consumption Standards
                                          [Gallons per 1,000 ton-miles]
----------------------------------------------------------------------------------------------------------------
                                                              Dry van                    Refrigerated van
                   Model years                   ---------------------------------------------------------------
                                                       Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
                                               Voluntary Standards
----------------------------------------------------------------------------------------------------------------
2018 to 2020....................................          8.1532         14.1454          8.2515         14.4401
----------------------------------------------------------------------------------------------------------------

                                               Mandatory Standards
----------------------------------------------------------------------------------------------------------------
2021 to 2023....................................          7.9568         13.9489          8.0550         14.3418
2024 to 2026....................................          7.7603         13.8507          7.9568         14.1454
2027 and later..................................          7.5639         13.7525          7.8585         14.1454
----------------------------------------------------------------------------------------------------------------

    (C) For purposes of certifying vehicles to fuel consumption
standards, manufacturers must divide their product lines into vehicles
families that have similar emissions and fuel consumption features, as
specified by EPA in 40 CFR part 1037.230, and these families will be
subject to the applicable standards. Each vehicle family is limited to
a single model year.
    (2) Subfamily standards. Manufacturers may specify a Family
Emission Limit (FEL) in terms of fuel consumption for each vehicle
subfamily. The FEL may not be less than the result of fuel consumption
modeling from 40 CFR 1037.520. The FEL is the fuel consumption standard
for the vehicle subfamily instead of the standard specified in
paragraph (e)(1)(ii) and (iii) of this section and can be used for
calculating fuel consumption credits in accordance with Sec.  535.7.
Manufacturers may not use averaging for non-box trailers, partial-aero
trailers, or non-aero trailers that meet standards under paragraph
(e)(1) of this section, and may not use fuel consumption credits for
banking or trading for any trailers.
    (3) Useful life. The fuel consumption standards of this section
apply for a useful life equal to 10 years.

Sec.  535.6  Measurement and calculation procedures.

    Determine all vehicle parameters used for testing in accordance
with EPA's provisions in 40 CFR 1037.140. Manufacturers conducting
testing for certification or annual demonstration testing and providing
CO2 emissions data to EPA must also provide equivalent fuel
consumption results for all values. NHTSA and EPA reserve the right to
verify separately or in coordination the results of any testing and
measurement established by manufacturers in complying with the
provisions of this program and as specified in 40 CFR 1037.301 and
Sec.  535.9. Any carry over data from the Phase 1 program may be
carried into the Phase 2 only with approval from EPA and by using good
engineering judgment considering differences in test protocols for
testing procedure.
    (a) Heavy-duty pickup trucks and vans. This section describes the
testing a manufacturer must perform for each model year and the method
for determining the fleet fuel consumption performance to show
compliance with the fleet average fuel consumption standard for heavy-
duty pickup trucks and vans in Sec.  535.5(a).
    (1) For each model year, the heavy-duty pickup trucks and vans
selected by a manufacturer to comply with fuel consumption standards in
Sec.  535.5(a) must be used to determine the manufacturer's fleet
average fuel consumption performance. If the manufacturer's fleet
includes conventional and advanced technology heavy-duty pickup trucks
and vans, the fleet should be sub-divided into two separate vehicle
fleets, with all of the conventional vehicles in one fleet and all of
the advanced technology vehicles in the other fleet.
    (2) Vehicles in each fleet should be divided into test groups or
subconfigurations according to EPA in 40 CFR part 86, subpart S.
    (3) Test and measure the CO2 emissions test results for
the selected vehicles and determine the CO2 emissions test
group result, in grams per mile in accordance with 40 CFR part 86,
subpart S.
    (i) Perform exhaust testing on vehicles fueled by conventional and
alternative fuels, including dedicated and dual-fueled (multi-fuel and
flexible-fuel) vehicles and measure the CO2 emissions test
result.
    (ii) Adjust the CO2 emissions test result of dual-fueled
vehicles using a weighted average of your emission results as specified
in 40 CFR 600.510-12(k) for light-duty trucks.
    (iii) All electric vehicles are deemed to have zero emissions of
CO2, CH4, and N2O. No emission testing
is required for such electric vehicles. Assign the fuel consumption
test group result to a value of zero gallons per 100 miles in paragraph
(a)(4) of this section.
    (iv) Test cab-complete and incomplete vehicles using the applicable
complete sister vehicles as determined in 40 CFR part 86.
    (v) Test loose engines using applicable complete vehicles as
determined in 40 CFR part 86.
    (vi) Manufacturers can choose to analytically derive CO2
emission rates (ADCs) for test groups or subconfigurations. Calculate
the ADCs for test groups or subconfigurations in accordance with 40 CFR
86.1819-14 (g).
    (4) Calculate equivalent fuel consumption test group results, in
gallons per 100 miles, from CO2 emissions test group
results, in grams per miles, and round to the nearest 0.001 gallon per
100 miles.
    (i) Calculate the equivalent fuel consumption test group results as
follows for compression-ignition vehicles and alternative fuel
compression-ignition vehicles. CO2 emissions test group
result (grams per mile)/10,180 grams per gallon of diesel fuel) x
(10\2\) = Fuel consumption test group result (gallons per 100 mile).
    (ii) Calculate the equivalent fuel consumption test group results
as follows for spark-ignition vehicles and alternative fuel spark-
ignition vehicles. CO2 emissions test group result (grams
per mile)/8,877 grams per gallon of gasoline fuel) x (10\2\) = Fuel
consumption test group result (gallons per 100 mile).
    (5) Calculate the fleet average fuel consumption result, in gallons
per 100 miles, from the equivalent fuel consumption test group results
and round the fuel consumption result to the nearest 0.001 gallon per
100 miles. Calculate the fleet average fuel consumption result using
the following equation.

[GRAPHIC] [TIFF OMITTED] TP13JY15.109

Where:

Fuel Consumption Test Group Resulti = fuel consumption performance
for each test group as defined in 49 CFR 523.4.
Volumei = production volume of each test group.

    (6) Compare the fleet average fuel consumption standard to the
fleet average fuel consumption performance. The fleet average fuel
consumption performance must be less than or equal to the fleet fuel
consumption standard to comply with standards in Sec.  535.5(a).
    (b) Heavy-duty vocational vehicles and tractors. This section
describes the testing a manufacturer must perform and the method for
determining fuel consumption performance to show compliance with the
fuel consumption standards for vocational vehicles and tractors in
Sec.  535.5(b) and (c).
    (1) Select vehicles and vehicle family configurations to test as
specified in 40 CFR 1037.230 for vehicles that make up each of the
manufacturer's regulatory subcategories of vocational vehicles and
tractors.
    (2) Determine the CO2 emissions and fuel consumption
results for all vehicles(conventional, alternative fueled and advanced
technology vehicles) using the Greenhouse Emissions Model (GEM) in
accordance with 40 CFR part 1037, subpart F. Vocational vehicles and
tractors are modeled using the following inputs in the GEM model.
    (3) For Phase 1, all of the following GEM inputs apply for sleeper
cab tractors, and day cab tractors. Some do not apply for vocational
vehicles and other tractor regulatory subcategories, as follows:
    (i) Manufacturers must identify vehicles according to their
regulatory subcategory, as defined in Sec.  535.4, for use in GEM (such
as ``Class 8 Combination--Sleeper Cab--High Roof'').
    (ii) Coefficient of aerodynamic drag in accordance with 40 CFR
1037.520 and 1037.525. Do not use for vocational vehicles.
    (iii) Steer tire rolling resistance for low rolling resistance
tires in accordance with 40 CFR 1037.520 and 1037.650.
    (iv) Drive tire rolling resistance for low rolling resistance tires
in accordance with 40 CFR 1037.520 and 1037.650.
    (v) Vehicle speed limit as governed by vehicles speed limiters in
accordance with 40 CFR 1037.520 and 1037.640. Do not use for vocational
vehicles.
    (vi) Vehicle weight reduction as provided in accordance with 40 CFR
1037.520. Do not use for vocational vehicles.
    (vii) Extended idle reduction credit using automatic engine
shutdown systems in accordance with 40 CFR 1037.520 and 1037.660. Do
not use for vehicles other than Class 8 sleeper cabs.
    (4) For Phase 1, engine performance and the advanced technologies
equipped on vocational vehicles and tractors are tested separately as
follows:
    (i) Test results for engines installed in vocational vehicles and
tractors, for both conventional and alternative fueled vehicles, are
determined in accordance with paragraph (c) of this section.
    (ii) Improvements for advanced technologies are determined as
follows:
    (A) Test hybrid vehicles with power take-off in accordance with 40
CFR 1037.540.
    (B) Vehicles with post-transmission hybrid systems are determined
in accordance with 40 CFR 1037.550.
    (5) For Phase 2, manufacturers are allowed to add additional
specifications to improve fuel consumption performance in GEM as
specified in 40 CFR 1037.520. Additional GEM inputs apply for Phase 2
tractors and vocational vehicles as follows:
    (i) Transmission make, model, type, and the gear ratio for every
available forward gears.
    (ii) Engine make, model, fuel type, engine family name, calibration
identification. Also identify whether the engine is subject to spark-
ignition or compression-ignition standards under 40 CFR part 1036.
    (iii) Drive axle ratio. If a vehicle is designed with two or more
user-selectable axle ratios, use the axle ratio that is expected to be
engaged for the greatest driving distance.
    (iv) Various engine and vehicle operational characteristics, as
described in 40 CFR 1037.520(f).
    (v) Engine fuel maps, which include an idle fuel map for vocational
vehicles.
    (vi) Engine full-load torque curve and motoring torque curve.
    (vii) Loaded tire radius, based upon nominal design specifications,
expressed to the nearest 0.01m as described in 40 CFR 1037.140.
    (viii) Hybrid power take-off (for vocational vehicles only).
    (6) Manufacturers may certify their vehicles based on powertrain
testing as described in 40 CFR 1037.550, rather than fuel maps, to
characterize fuel consumption rates at different speed and torque
values.
    (7) Emergency vehicles complying with alternative standards
specified in Sec.  535.5(b) and 40 CFR 1037.105(b)(4), run GEM by
identifying the vehicle as an emergency vehicle and enter values for
tire rolling resistance only.
    (8) You may use a default fuel map for specialty vehicles using
engines certified to alternate standards under 40 CFR 1037.605.
    (9) Manufacturers of vehicles that run on fuel other than gasoline
or diesel, should use good engineering judgment to adjust modeling
output values to account for the physical properties of the fuel.
    (10) From the GEM results, select the CO2 family
emissions level (FEL) and equivalent fuel consumption values for
vocational vehicle and tractor families in each regulatory subcategory
for each model year. Equivalent fuel consumption FELs are derived in
GEM and expressed to the nearest 0.0001 gallons per 1000 ton-mile. For
families containing multiple subfamilies, identify the FELs for each
subfamily.
    (11) All electric vehicles are deemed to have zero CO2
emissions and fuel consumption. No emission testing is required for
such electric vehicles. Assign the vehicle family with a fuel
consumption FEL result to a value of zero gallons per 1000-ton miles.
    (c) [Reserved]
    (d) Heavy-duty engines. This section describes the testing a
manufacturer must perform and the method for determining fuel
consumption performance to show compliance with the fuel consumption
standards for engines in Sec.  535.5(d). Each engine must be tested to
the primary intended service class that it is designed for in
accordance with 40 CFR 1036.108. For engines using aftertreatment
technology with infrequent regeneration events test in accordance with
40 CFR 86.004-28,
    (1) Manufacturers must select emission-data engines and engine
family configurations to test as specified in 40 CFR part 86 for
engines in heavy-duty pickup trucks and vans and 40 CFR 1036.235 for
engines installed in truck tractors and vocational vehicles that make
up each of the manufacture's regulatory subcategories.
    (2) Test the CO2 emissions for each emissions-data
engine subject to the

standards in Sec.  535.5(d) using the procedures and equipment
specified in 40 CFR part 1036, subpart F. Measure the CO2
emissions in grams per hp-hr as specified in 40 CFR 1036.501. For
medium and heavy heavy-duty engines certified as tractor engines,
measure CO2 emissions using the steady-state duty cycle
specified in 40 CFR 86.1362. For medium and heavy heavy-duty engines
certified as both tractor and vocational engines, measure
CO2 emissions using the steady-state duty cycle and the
transient duty cycle (sometimes referred to as the FTP engine cycle),
both of which are specified in 40 CFR part 86, subpart N.
    (i) Perform exhaust testing on each fuel type for conventional,
dedicated, dual-fueled (multi-fuel, and flexible-fuel) vehicles and
measure the CO2 emissions level as specified in 40 CFR part
1036.
    (ii) Adjust the CO2 emissions result of dual-fueled
vehicles using a weighted average of the demonstrated emission results
as specified in 40 CFR 1036.225. If EPA disapproves a manufacturer's
dual-fueled vehicle demonstrated use submission, NHTSA will require the
manufacturer to only use the test results with 100 percent conventional
fuel to determine the fuel consumption of the engine.
    (iii) All electric vehicles are deemed to have zero emissions of
CO2 and zero fuel consumption. No emission or fuel
consumption testing is required for such electric vehicles.
    (3) Determine the CO2 emissions for the family
certification level (FCL) from the emissions test results in paragraph
(c)(2) of this section for engine families within the heavy-duty engine
regulatory subcategories for each model year.
    (i) If a manufacturer certifies an engine family for use both as a
vocational engine and as a tractor engine, the manufacturer must split
the family into two separate subfamilies in accordance with 40 CFR
1036.230. The manufacturer may assign the numbers and configurations of
engines within the respective subfamilies at any time prior to the
submission of the end-of-year report required by 40 CFR 1036.730 and
Sec.  535.8. The manufacturer must track into which type of vehicle
each engine is installed, although EPA may allow the manufacturer to
use statistical methods to determine this for a fraction of its
engines.
    (ii) The following engines are excluded from the engine families
used to determined 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:
    (A) Engines certified as hybrid engines or power packs.
    (B) Engines certified as hybrid engines designed with PTO
capability and that are sold with the engine coupled to a transmission.
    (C) Engines with Rankine cycle waste heat recovery.
    (4) Calculate equivalent fuel consumption values for emissions FCLs
and the CO2 levels for certified engines, in gallons per 100
hp-hr and round each fuel consumption value to the nearest 0.0001
gallon per 100 hp-hr.
    (i) Calculate equivalent fuel consumption FCL values for
compression-ignition engines and alternative fuel compression-ignition
engines. CO2 FCL value (grams per hp-hr)/10,180 grams per
gallon of diesel fuel) x (10\2\) = Fuel consumption FCL value (gallons
per 100 hp-hr).
    (ii) Calculate equivalent fuel consumption FCL values for spark-
ignition engines and alternative fuel spark-ignition engines.
CO2 FCL value (grams per hp-hr)/8,877 grams per gallon of
gasoline fuel) x (10\2\) = Fuel consumption FCL value (gallons per 100
hp-hr).
    (iii) Manufacturers may carryover fuel consumption data from a
previous model year if allowed to carry over emissions data for EPA in
accordance with 40 CFR 1036.235.
    (iv) If a manufacturer uses an alternate test procedure under 40
CFR 1065.10 and subsequently the data is rejected by EPA, NHTSA will
also reject the data.
    (e) Heavy-duty trailers. This section describes the testing a
manufacturer must perform and the method for determining fuel
consumption performance to show compliance with the fuel consumption
standards for trailers in Sec.  535.5(e).
    (1) Select trailer family configurations to test as specified in 40
CFR 1037.235 for trailers that make up each of the manufacture's