#### § 535.5 Standards.

(a) *Heavy-duty pickup trucks and vans.* Each manufacturer's fleet of heavy-duty pickup trucks and vans shall comply with the fuel consumption standards in this paragraph (a) expressed in gallons per 100 miles. Each vehicle must be manufactured to comply for its full useful life. For the Phase 1 program, if the manufacturer's fleet includes conventional vehicles (gasoline, diesel and alternative fueled vehicles) and advanced technology vehicles (hybrids with powertrain designs that include energy storage systems, vehicles with waste heat recovery, electric vehicles and fuel cell vehicles), it may divide its fleet into two separate fleets each with its own separate fleet average fuel consumption standard which the manufacturer must comply with the requirements of this paragraph (a). For Phase 2, manufacturers may calculate their fleet average fuel consumption standard for a conventional fleet and multiple advanced technology vehicle fleets. Advanced technology vehicle fleets should be separated into plug-in hybrid electric vehicles, electric vehicles, and fuel cell vehicles. The standards in this paragraph (a) correspond to EPA requirements specified in 40 CFR 86.1819-14. When applying the fuel consumption standards in this paragraph (a), manufacturers must use the same options they use to comply with EPA in 40 CFR part 86, subpart S in terms of grouping vehicles and/or engines for purposes of determining applicable standards and determining compliance (*i.e.,* the vehicles and/or engines and must be grouped in the same way for purposes of this paragraph (a) as they are grouped for compliance with EPA's requirements in 40 CFR part 86, subpart S). Engines that are installed in vehicles that are subject to the standards in this paragraph are not subject to the standards in paragraph (d) of this section and may not optionally comply with paragraph (d).

(1) *Mandatory standards.* For model years 2016 and later, each manufacturer must comply with the fleet average standard derived from the unique subconfiguration target standards (or groups of subconfigurations approved by EPA in accordance with 40 CFR 86.1819) 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 years 2021 through 2029. NHTSA's Phase 3 HDPUV target standards apply for model year 2030 and later.

(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 1 to paragraph (a)(2)(ii), 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 equation: 1 to this paragraph (a)(2)(ii).

Equation 1 to Paragraph (a)(2)(ii)

Subconfiguration Target Standard (gallons per 100 miles) = [c × (WF)] + d

Where:

WF = Work Factor = [0.75 × (Payload Capacity + Xwd)] + [0.25 × 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)

| Model year(s) | c | d |
| --- | --- | --- |
| **Phase 1 Alternative 1—Fixed Target Standards** |
| **Compression Ignition (CI) Vehicle Coefficients** |
| 2016 to 2018 | 0.0004322 | 3.330 |
| 2019 to 2020 | 0.0004086 | 3.143 |
| **SI Vehicle Coefficients** |
| 2016 to 2017 | 0.0005131 | 3.961 |
| 2018 to 2020 | 0.0004086 | 3.143 |
| **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 to 2029 | 0.0003418 | 2.633 |
| 2030 | 0.00030762 | 2.370 |
| 2031 | 0.00027686 | 2.133 |
| 2032 | 0.00024917 | 1.919 |
| 2033 | 0.00022924 | 1.766 |
| 2034 | 0.00021090 | 1.625 |
| 2035 | 0.00019403 | 1.495 |
| **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 to 2029 | 0.0004152 | 3.196 |
| 2030 | 0.00037368 | 2.876 |
| 2031 | 0.00033631 | 2.589 |
| 2032 | 0.00030268 | 2.330 |
| 2033 | 0.00027847 | 2.143 |
| 2034 | 0.00025619 | 1.972 |
| 2035 | 0.00023569 | 1.814 |

Table 1 to Paragraph (a)(2)(ii)—Coefficients for Mandatory Subconfiguration Target Standards

(3) *Fleet average fuel consumption standard.*

(i) For the Phase 1 program, calculate each manufacturer's fleet average fuel consumption standard for a conventional fleet and a combined advanced technology fleet 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:

Where:

Subconfiguration Target Standard*i* = fuel consumption standard for each group of vehicles with same payload, towing capacity and drive configuration (gallons per 100 miles).

Volume*i* = 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 § 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 § 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:

| 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 |

Table 7—Coefficients for Voluntary Subconfiguration Target Standards

(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 certain complete or cab-complete vehicles to the fuel consumption standards of this section. All vehicles optionally certified under this paragraph (6) are deemed to be subject to the fuel consumption standards of this section given the following conditions:

(i) For fuel consumption compliance, manufacturers may certify any complete or cab-complete spark-ignition vehicles above 14,000 pounds GVWR and at or below 26,000 pounds GVWR to the fuel consumption standards of this section.

(ii) Manufacturers may apply the provisions of this section to cab-complete vehicles based on a complete sister vehicle. In unusual circumstances, manufacturers may ask the agencies to apply these provisions to Class 2b or Class 3 incomplete vehicles that do not meet the definition of cab-complete.

(A) Except as specified in paragraph (a)(6)(iii) of this section, for purposes of this section, a complete sister vehicle is a complete vehicle of the same vehicle configuration as the cab-complete vehicle. A manufacturer may not apply the provisions of this paragraph (6) to any vehicle configuration that has a four-wheel rear axle if the complete sister vehicle has a two-wheel rear axle.

(B) Calculate the target value for the fleet-average fuel consumption standard under paragraph (a)(3) of this section based on the work factor value that applies for the complete sister vehicle.

(C) Test these cab-complete vehicles using the same equivalent test weight and other dynamometer settings that apply for the complete vehicle from which you used the work factor value (the complete sister vehicle). For fuel consumption certification, manufacturers may submit the test data from that complete sister vehicle instead of performing the test on the cab-complete vehicle.

(D) Manufacturers are not required to produce the complete sister vehicle for sale to use the provisions of this paragraph (a)(6)(ii). This means the complete sister vehicle may be a carryover vehicle from a prior model year or a vehicle created solely for the purpose of testing.

(iii) For fuel consumption purposes, if a cab-complete vehicle is not of the same vehicle configuration as a complete sister vehicle due only to certain factors unrelated to coastdown performance, manufacturers may use the road-load coefficients from the complete sister vehicle for certification testing of the cab-complete vehicle, but it may not use fuel consumption data from the complete sister vehicle for certifying the cab-complete vehicle.

(7) *Loose engines.* For model year 2023 and earlier spark-ignition engines with identical hardware compared with engines used in vehicles certified to the standards of this section, where such engines are sold as loose engines or as engines installed in incomplete vehicles that are not cab-complete vehicles. Manufacturers may certify such engines to the standards of this section, subject to the following provisions:

(i) For 2020 and earlier model years, the maximum allowable U.S.-directed production volume of engines manufacturers may sell under this paragraph (7) in any given model year is ten percent of the total U.S-directed production volume of engines of that design that the manufacturer produces for heavy-duty applications for that model year, including engines it produces for complete vehicles, cab-complete vehicles, and other incomplete vehicles. The total number of engines a manufacturer may certify under this paragraph (7), of all engine designs, may not exceed 15,000 in any model year. Engines produced in excess of either of these limits are not covered by your certificate. For example, a manufacturer produces 80,000 complete model year 2017 Class 2b pickup trucks with a certain engine and 10,000 incomplete model year 2017 Class 3 vehicles with that same engine, and the manufacturer did not apply the provisions of this paragraph (a)(7) to any other engine designs, it may produce up to 10,000 engines of that design for sale as loose engines under this paragraph (a)(7). If a manufacturer produced 11,000 engines of that design for sale as loose engines, the last 1,000 of them that it produced in that model year 2017 would be considered uncertified.

(ii) For model years 2021 through 2023, the U.S.-directed production volume of engines manufacturers sell under this paragraph (a)(7) in any given model year may not exceed 10,000 units. This paragraph (a)(7) does not apply for engines certified to the standards of paragraph (d) of this section and 40 CFR 1036.108.

(iii) Vehicles using engines certified under this paragraph (a)(7) are subject to the fuel consumption and emission standards of paragraph (b) of this section and 40 CFR 1037.105 and engine standards in 40 CFR 1036.150(j).

(iv) For certification purposes, engines are deemed to have a fuel consumption target values and test result equal to the fuel consumption target value and test result for the complete vehicle in the applicable test group with the highest equivalent test weight, except as specified in paragraph (a)(7)(iv)(B) of this section. Manufacturers use these values to calculate target values and the fleet-average fuel consumption rate. Where there are multiple complete vehicles with the same highest equivalent test weight, select the fuel consumption target value and test result as follows:

(A) If one or more of the fuel consumption test results exceed the applicable target value, use the fuel consumption target value and test result of the vehicle that exceeds its target value by the greatest amount.

(B) If none of the fuel consumption test results exceed the applicable target value, select the highest target value and set the test result equal to it. This means that the manufacturer may not generate fuel consumption credits from vehicles certified under this paragraph (a)(7).

(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) *Advanced, innovative, and off-cycle technologies.* For vehicles subject to Phase 1 standards, manufacturers may generate separate credit allowances for advanced and innovative technologies as specified in § 535.7(f)(1) and (2). For vehicles subject to Phase 2 standards, manufacturers may generate separate credits allowance for off-cycle technologies in accordance with § 535.7(f)(2) through model year 2029. Separate credit allowances for advanced technology vehicles cannot be generated; instead, manufacturers may use the credit specified in § 535.7(f)(1)(ii) through model year 2027.

(10) *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.

(11) *Compliance with standards.* A manufacturer complies with the standards of this part as described in § 535.10.

(b) *Heavy-duty vocational vehicles.* Each manufacturer building complete or incomplete heavy-duty vocational vehicles shall comply with the fuel consumption standards in this paragraph (b) expressed in gallons per 1,000 ton-miles. When applying the fuel consumption standards in this paragraph (b), manufacturers must use the same options they use to comply with EPA in 40 CFR 1037.105 in terms of grouping vehicles and/or engines for purposes of determining applicable standards and determining compliance (*i.e.,* the vehicles and/or engines and must be grouped in the same way for purposes of this paragraph (b) as they are grouped for compliance with EPA's requirements in 40 CFR 1037.105). Engines used in heavy-duty vocational vehicles shall comply with the standards in paragraph (d) of this section. Each vehicle must be manufactured to comply for its full useful life. Standards apply to the vehicle subfamilies based upon the vehicle service classes within each of the vocational vehicle regulatory subcategories in accordance with § 535.4 and based upon the applicable modeling and testing specified in § 535.6. Determine the duty cycles that apply to vocational vehicles according to 40 CFR 1037.140 and 1037.150(z).

(1) *Mandatory standards.* Heavy-duty vocational vehicle subfamilies 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 vehicle subfamilies 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 vehicle category is subdivided by GVWR into three regulatory subcategories as defined in § 535.4, each with its own assigned standard.

(ii) For model years 2021 and later, the heavy-duty vocational vehicle category is subdivided into 15 regulatory subcategories depending upon whether vehicles are equipped with a compression or spark-ignition engine, as defined in § 535.4. Standards also differ based upon vehicle service class and intended vehicle duty cycles. See 40 CFR 1037.140 and 1037.150(z).

(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 1037.230. These families will be subject to the applicable standards. Each vehicle family is limited to a single model year.

(A) Vocational vehicles including custom chassis vehicles must use qualified automatic tire inflation systems or tire pressure monitoring systems for wheels on all axles.

(B) [Reserved]

(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 § 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:

| Regulatory subcategories | VocationalLHD vehicles | VocationalMHD vehicles | VocationalHHD 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 |

Table 8—Phase 1 Vocational Vehicle Fuel Consumption Standards

[Gallons per 1000 ton-miles]

(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:

| **Model Years 2021 through 2023 Standards for CI Vehicles** |
| --- |
| Duty cycle | LHD vocationalvehicles | MHD vocationalvehicles | Vocational HHDvehicles |
| Urban | 41.6503 | 29.0766 | 30.2554 |
| Multi-Purpose | 36.6405 | 26.0314 | 25.6385 |
| Regional | 30.5501 | 22.9862 | 20.1375 |
| **Model Years 2021 through 2023 Standards for SI Vehicles** |
| Duty cycle | LHD vocationalvehicles | MHD and HHDvocational vehicles | N/A |
| Urban | 51.8735 | 36.9078 | N/A |
| Multi-Purpose | 45.7972 | 32.9695 | N/A |
| Regional | 37.6955 | 29.3687 | N/A |
| **Model Years 2024 through 2026 Standards for CI Vehicles** |
| Duty cycle | Vocational LHD vehicles | Vocational MHDvehicles | Vocational HHDvehicles |
| Urban | 37.8193 | 26.6208 | 27.7996 |
| Multi-Purpose | 33.7917 | 24.1650 | 23.7721 |
| Regional | 29.0766 | 21.7092 | 19.0570 |
| **Model Years 2024 through 2026 Standards for SI Vehicles** |
| Duty cycle | Vocational LHD vehicles | Vocational MHD and HHD vehicles | N/A |
| Urban | 48.6103 | 34.8824 | N/A |
| Multi-Purpose | 43.3217 | 31.3942 | N/A |
| Regional | 36.4577 | 28.2435 | N/A |
| **Model Years 2027 and later Standards for CI Vehicles** |
| Duty cycle | Vocational LHD vehicles | Vocational MHDvehicles | Vocational HHDvehicles |
| Urban | 36.0511 | 25.3438 | 26.4244 |
| Multi-Purpose | 32.4165 | 23.0845 | 22.5933 |
| Regional | 28.5855 | 21.4145 | 18.5658 |
| **Model Years 2027 and later Standards for SI Vehicles** |
| Duty cycle | Vocational LHDvehicles | Vocational MHD andHHD vehicles | N/A |
| Urban | 46.4724 | 33.4196 | N/A |
| Multi-Purpose | 41.8589 | 30.1564 | N/A |
| Regional | 35.8951 | 27.7934 | N/A |

Table 9 to Paragraph (b)(4)—Phase 2 Vocational Vehicle Fuel Consumption Standards

[Gallons per 1,000 ton-miles]

(5) *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 § 535.7.

(6) *Alternate standards for custom chassis vehicles for model years 2021 and later.* Manufacturers may elect to certify certain vocational vehicles to the alternate standards for custom chassis vehicles specified in this paragraph (b)(6) instead of the standards specified in paragraph (b)(4) of this section. Note that, although these standards were established for custom chassis vehicles, manufacturers may apply these provisions to any qualifying vehicle even though these standards were established for custom chassis vehicles. For example, large diversified vehicle manufacturers may certify vehicles to the refuse hauler standards of this section as long as the manufacturer ensures that those vehicles qualify as refuse haulers when placed into service. GEM simulates vehicle operation for each type of vehicle based on an assigned vehicle service class, independent of the vehicle's actual characteristics, as shown in Table 10 of this section; however, standards apply for the vehicle's useful life based on its actual characteristics as specified in paragraph (b)(10) of this section. Vehicles certified to these alternative standards must use engines certified to requirements under paragraph (d) of this section and 40 CFR part 1036 for the appropriate model year, except that motor homes and emergency vehicles may use engines certified with the loose-engine provisions of paragraph (a)(7) of this section and 40 CFR 1037.150(m). This also applies for vehicles meeting standards under paragraphs (b)(6)(iv) through (vi) of this section. The fuel consumption standards for custom chassis vehicles are given in the following table:

| Vehicle type1 | Assigned vehicle service class | MY 2021 | MY 2027 |
| --- | --- | --- | --- |
| Coach Bus | HHD Vehicle | 20.6287 | 20.1375 |
| Motor Home | MDH Vehicle | 22.3969 | 22.2004 |
| School Bus | MHD Vehicle | 28.5855 | 26.6208 |
| Other bus | HHD Vehicle | 29.4695 | 28.0943 |
| Refuse hauler | HHD Vehicle | 30.7466 | 29.2731 |
| Concrete mixer | HHD Vehicle | 31.3360 | 31.0413 |
| Mixed-use vehicle | HHD Vehicle | 31.3360 | 31.0413 |
| Emergency Vehicle | HHD Vehicle | 31.8271 | 31.3360 |
| 1 Vehicle types are generally defined in § 535.3. “Other bus” includes any bus that is not a school bus or a coach bus. A “mixed-use vehicle” is one that meets at least one of the criteria specified in 40 CFR 1037.631(a)(1) or at least one of the criteria in 40 CFR 1037.631(a)(2), but not both. |

Table 10—Phase 2 Custom Chassis Fuel Consumption Standards

[Gallon per 1,000 ton-mile]

(i) Manufacturers may generate or use fuel consumption credits for averaging to demonstrate compliance with the alternative standards as described in § 535.7(c). This requires that manufacturers specify a Family Emission Limit (FEL) for fuel consumption for each vehicle subfamily. The FEL may not be less than the result of emission modeling as described in this paragraph (b). These FELs serve as the fuel consumption standards for the vehicle subfamily instead of the standards specified in this paragraph (b)(6). Manufacturers may only use fuel consumption credits for vehicles certified to the optional standards in this paragraph (b)(6) as specified in § 535.7(c)(6) through (8) and you may not bank or trade fuel consumption credits from any vehicles certified under this paragraph (b)(6).

(ii) For purposes of this paragraph (b)(6), each separate vehicle type identified in Table 10 of this section is in a separate averaging set.

(iii) For purposes of emission and fuel consumption modeling under 40 CFR 1037.520, consider motor homes and coach buses to be subject to the Regional duty cycle, and consider all other vehicles to be subject to the Urban duty cycle.

(iv) Emergency vehicles are deemed to comply with the standards of this paragraph (6) if manufacturers use tires with TRRL at or below 8.4 kg/ton (8.7 g/ton for model years 2021 through 2026).

(v) Concrete mixers are deemed to comply with the standards of this paragraph (6) if manufacturers use tires with TRRL at or below 7.1 kg/ton (7.6 g/ton for model years 2021 through 2026).

(vi) Motor homes are deemed to comply with the standards of this paragraph (b)(6) if manufacturers use the following technologies:

(A) Tires with TRRL at or below 6.0 kg/ton (6.7 g/ton for model years 2021 through 2026).

(B) Automatic tire inflation systems or tire pressure monitoring systems with wheels on all axles.

(C) Tire pressure monitoring systems must use low pressure warning and malfunction telltales in clear view of the driver as specified in S4.3 and S4.4 of 49 CFR 571.138.

(vii) Small business manufacturers using the alternative standards for custom chassis vehicles under this paragraph (b)(6) may use fuel consumption credits subject to the unique provisions in § 535.7(a)(9).

(7) *Advanced, innovative and off-cycle technologies.* For vocational vehicles subfamilies subject to Phase 1 standards, manufacturers must create separate vehicle subfamilies for vehicles that contain advanced or innovative technologies and group those vehicles together in a vehicle subfamily if they use the same advanced or innovative technologies. Manufacturers may generate s separate credit allowances for advanced and innovative technologies as specified in § 535.7(f)(1) and (2). For vehicles subfamilies subject to Phase 2 standards, manufacturers may generate separate credit allowances for off-cycle technologies in accordance with § 535.7(f)(2). Separate credit allowances for advanced technology vehicles cannot be generated but instead manufacturers may use the credit multipliers specified in § 535.7(f)(1)(iv) through model year 2026.

(8) *Certifying across service classes.* A manufacturer may optionally certify a vocational vehicle subfamilies to the standards and useful life applicable to a heavier vehicle service class (such as MHD vocational vehicles instead of LHD vocational vehicles). Provisions related to generating fuel consumption credits apply as follows:

(i) If a manufacturer certifies all its vehicles from a given vehicle service class in a given model year to the standards and useful life that applies for a heavier vehicle service class, it may generate credits as appropriate for the heavier service class.

(ii) Class 8 hybrid vehicles with light or medium heavy-duty engines may be certified to compression-ignition standards for the Heavy HDV service class. A manufacturer may generate and use credits as allowed for the Heavy HDV service class.

(iii) Except as specified in paragraphs (b)(8)(i) and (ii) of this section, a manufacturer may not generate credits with the vehicle. If you include lighter vehicles in a subfamily of heavier vehicles with an FEL below the standard, exclude the production volume of lighter vehicles from the credit calculation. Conversely, if a manufacturer includes lighter vehicles in a subfamily with an FEL above the standard, it must include the production volume of lighter vehicles in the credit calculation.

(9) *Off-road exemptions.* This section provides an exemption for heavy-duty vocational vehicle subfamilies, including vocational tractors that are intended to be used extensively in off-road environments such as forests, oil fields, and construction sites from the fuel consumption standards in this paragraph (b). Vehicle exempted by this part do not comply with vehicle standards in this paragraph (b), but the engines in these vehicles must meet the engine requirements of paragraph (d) of this section. Note that manufacturers may not include these exempted vehicles in any credit calculations under this part.

(i) *Qualifying criteria.* Vocational vehicles with a date of manufacture before January 1, 2021 automatically qualify for an exemption under this paragraph (b)(9) if the tires installed on the vehicle have a maximum speed rating at or below 55 miles per hour. Vocational vehicles intended for off-road use are exempt without request, subject to the provisions of this section, if they are primarily designed to perform work off-road (such as in oil fields, mining, forests, or construction sites), and they meet at least one of the criteria of paragraph (b)(9)(i)(A) of this section and at least one of the criteria of paragraph (b)(9)(i)(B) of this section. See paragraph (b)(6) of this section for alternate standards that apply for vehicles meeting only one of these sets of criteria.

(A) The vehicle must have affixed components designed to work inherently in an off-road environment (such as hazardous material equipment or off-road drill equipment) or be designed to operate at low speeds such that it is unsuitable for normal highway operation.

(B) The vehicle must meet one of the following criteria:

(*1*) Have an axle that has a gross axle weight rating (GAWR) at or above 29,000 pounds.

(*2*) Have a speed attainable in 2.0 miles of not more than 33 mi/hr.

(*3*) Have a speed attainable in 2.0 miles of not more than 45 mi/hr, an unloaded vehicle weight that is not less than 95 percent of its gross vehicle weight rating, and no capacity to carry occupants other than the driver and operating crew.

(*4*) Have a maximum speed at or below 54 mi/hr. A manufacturer may consider the vehicle to be appropriately speed-limited if engine speed at 54 mi/hr is at or above 95 percent of the engine's maximum test speed in the highest available gear. A manufacturer may alternatively limit vehicle speed by programming the engine or vehicle's electronic control module in a way that is tamper-resistant.

(ii) *Tractors.* The provisions of this section may apply for tractors only if each tractor qualifies as a vocational tractor under paragraph (c)(9) of this section or is granted approval for the exemption as specified in paragraph (b)(9)(iii) of this section.

(iii) *Preliminary approval before certification.* If a manufacturers has unusual circumstances where it may be questionable whether its vehicles qualify for the off-road exemption of this part, the manufacturer may send the agencies information before finishing its application for certification (see 40 CFR 1037.205) for the applicable vehicles and ask for a preliminary informal approval. The agencies will review the request and make an appropriate determination in accordance with 40 CFR 1037.210. The agencies will generally not reverse a decision where they have given a manufacturer preliminary approval, unless the agencies find new information supporting a different decision. However, the agencies will normally not grant relief in cases where the vehicle manufacturer has credits or can otherwise comply with the applicable standards.

(iv) *Recordkeeping and reporting.*

(A) A manufacturers must keep records to document that its exempted vehicle configurations meet all applicable requirements of this section. Keep these records for at least eight years after you stop producing the exempted vehicle model. The agencies may review these records at any time.

(B) A manufacturers must also keep records of the individual exempted vehicles you produce, including the vehicle identification number and a description of the vehicle configuration.

(C) Within 90 days after the end of each model year, manufacturers must send to EPA a report as specified in § 535.8(g)(7) and EPA will make the report available to NHTSA.

(v) *Compliance.*

(A) Manufacturers producing vehicles meeting the off-road exemption criteria in paragraph (b)(9)(i) of this section or that are granted a preliminary approval comply with the standards of this part.

(B) In situations where a manufacturer would normally ask for a preliminary approval subject to paragraph (b)(9)(iii) of this section but introduces its vehicle into U.S. commerce without seeking approval first from the agencies, those vehicles violate compliance with the fuel consumption standards of this part and the EPA provisions under 40 CFR 1068.101(a)(1).

(C) If at any time, the agencies find new information that contradicts a manufacturer's use of the off-road exemption of this part, the manufacturers vehicles will be determined to be non-compliant with the regulations of this part and the manufacturer may be liable for civil penalties.

(10) *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 vocational LHD vehicles certified to Phase 1 standards.

(ii) 150,000 miles or 15 years, whichever comes first, for vocational LHD vehicles certified to Phase 2 standards.

(iii) 185,000 miles or 10 years, whichever comes first, for vocational MHD vehicles for Phase 1 and 2.

(iv) 435,000 miles or 10 years, whichever comes first, for vocational HHD vehicles for Phase 1 and 2.

(v) For Phase 1 credits calculated based on a useful life of 110,000 miles, multiply any banked credits carried forward for use into the Phase 2 program by 1.36. For Phase 1 credit deficits generated based on a useful life of 110,000 miles multiply the credit deficit by 1.36, if offsetting the shortfall with Phase 2 credits.

(11) *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.

(12) *Loose engines.* Manufacturers may certify certain spark-ignition engines along with chassis-certified heavy-duty vehicles where there are identical engines used in those vehicles as described in 40 CFR 86.1819(k)(8) and 40 CFR 1037.150(m). Vehicles in which those engines are installed are subject to standards under this part.

(13) *Compliance with Standards.* A manufacturer complies with the standards of this part as described in § 535.10.

(c) *Truck tractors.* Each manufacturer building truck tractors, except vocational tractors or vehicle constructed in accordance with 49 CFR 571.7(e), with a GVWR above 26,000 pounds shall comply with the fuel consumption standards in this paragraph (c) expressed in gallons per 1,000 ton-miles. When applying the fuel consumption standards in this paragraph (c), manufacturers must use the same options they use to comply with EPA in 40 CFR 1037.106 in terms of grouping vehicles and/or engines for purposes of determining applicable standards and determining compliance (*i.e.,* the vehicles and/or engines and must be grouped in the same way for purposes of this paragraph (c) as they are grouped for compliance with EPA's requirements in 40 CFR 1037.106). Engines used in heavy-duty truck tractors vehicles shall comply with the standards in paragraph (d) of this section. Each vehicle must be manufactured to comply for its full useful life. Standards apply to the vehicle subfamilies within each of the tractor vehicle regulatory subcategories in accordance with § 535.4 and 40 CFR 1037.230 and based upon the applicable modeling and testing specified in § 535.6. Determine the vehicles in each regulatory subcategory in accordance with 40 CFR 1037.140.

(1) *Mandatory standards.* For model years 2016 and later, each manufacturer's truck tractor subfamilies 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, the truck tractor category is divided into subcategories as described in § 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 subfamilies that have similar emissions and fuel consumption features, as specified by EPA in 40 CFR 1037.230, and these subfamilies will be subject to the applicable standards. Each vehicle subfamily 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 § 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:

| Regulatory subcategories | Day cab | Sleeper cab | 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 | NA |
| 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 | NA |
| 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 | 10.36346 | 7.90766 | 7.10216 | 5.14735 |
| Mid Roof | 11.11984 | 8.38900 | 7.66208 | |
| High Roof | 11.14931 | 8.40864 | 7.43615 | |
| **Phase 2—Model Years 2024 to 2026 Mandatory Standards** |
| Low Roof | 9.80354 | 7.48527 | 6.67976 | 4.93124 |
| Mid Roof | 10.52063 | 7.94695 | 7.22004 | |
| High Roof | 10.47151 | 7.89784 | 6.94499 | |
| **Phase 2—Model Years 2027 and later Mandatory Standards** |
| Low Roof | 9.44990 | 7.21022 | 6.29666 | 4.74460 |
| Mid Roof | 10.15717 | 7.66208 | 6.83694 | |
| High Roof | 9.82318 | 7.43615 | 6.31631 | |

Table 11—Truck Tractor Fuel Consumption Standards

[Gallons per 1,000 ton-miles]

(4) *Subfamily standards.* Manufacturers may generate or use fuel consumption credits for averaging, banking, and trading as described in § 535.7(c). This requires that manufacturers calculate a credit quantity if they specify a Family Emission Limit (FEL) that is different than the standard specified in this section. The FEL may not be less than the result of emission and fuel consumption modeling from 40 CFR 1037.520. These FELs serve as the emission standards for the specific vehicle subfamily instead of the standards specified in paragraph (2) of this section.

(5) *Alternate standards for tractors at or above 120,000 pounds GCWR.* Manufacturers may certify tractors at or above 120,000 pounds GCWR to the following fuel consumption standards in the following table:

| Regulatory subcategory | Model years 2021 through 2023 | Model years 2024 through 2026 | Model years 2027 and later |
| --- | --- | --- | --- |
| Heavy Class 8 Low-Roof Day Cab | 5.25540 | 4.99018 | 4.80354 |
| Heavy Class 8 Low-Roof Sleeper Cab | 4.62672 | 4.37132 | 4.16503 |
| Heavy Class 8 Mid-Roof Day Cab | 5.46169 | 5.18664 | 4.99018 |
| Heavy Class 8 Mid-Roof Sleeper Cab | 4.87230 | 4.60707 | 4.39096 |
| Heavy Class 8 High-Roof Day Cab | 5.35363 | 5.04912 | 4.77407 |
| Heavy Class 8 High-Roof Sleeper Cab | 4.62672 | 4.34185 | 4.02750 |

Table 12 to Paragraph (c)(5)—Alternate Fuel Consumption Standards for Tractors Above 120,000 Pounds GCWR for 2021 MY and Later

[Gallons per 1,000 ton-miles]

(6) *Advanced, innovative and off-cycle technologies.* For tractors subject to Phase 1 standards, manufacturers must create separate vehicle subfamilies for vehicles that contain advanced or innovative technologies and group those vehicles together in a vehicle subfamilies if they use the same advanced or innovative technologies. Manufacturers may generate separate credit allowances for advanced and innovative technologies as specified in § 535.7(f)(1) and (2). For vehicles subject to Phase 2 standards, manufacturers may generate separate credits allowance for off-cycle technologies in accordance with § 535.7(f)(2). Separate credit allowances for advanced technology vehicles cannot be generated but instead manufacturers may use the credit multipliers specified in § 535.7(f)(1)(iv) through model year 2026.

(7) *Certifying across service classes.* Manufacturers may certify Class 7 tractors to Class 8 tractors standards as follows:

(i) A manufacturer may optionally certify 4x2 tractors with heavy heavy-duty engines to the standards and useful life for Class 8 tractors, with no restriction on generating or using fuel consumption credits within the Class 8 averaging set.

(ii) A manufacturer may optionally certify a Class 7 tractor to the standards and useful life applicable to Class 8 tractors. Credit provisions apply as follows:

(A) If a manufacturer certifies all of its Class 7 tractors to Class 8 standards, it may use these Heavy HDV credits without restriction.

(B) This paragraph (c)(7)(ii)(B) applies if a manufacturer certifies some Class 7 tractors to Class 8 standards under this paragraph (c)(7)(ii) but not all of them. If a manufacturer includes Class 7 tractors in a subfamily of Class 8 tractors with an FEL below the standard, exclude the production volume of Class 7 tractors from the credit calculation. Conversely, if a manufacturer includes Class 7 tractors in a subfamily of Class 8 tractors with an FEL above the standard, it must include the production volume of Class 7 tractors in the credit calculation.

(8) *Expanded families.* Manufacturers may combine dissimilar vehicles into a single vehicle subfamilies for applying standards and for testing in special circumstances as follows:

(i) For a Phase 1 vehicle model that straddles a roof-height, cab type, or GVWR division, manufacturers can include all the vehicles in the same vehicle family if it certifies the vehicle family to the more stringent standard. For roof height, the manufacturer must certify to the taller roof standard. For cab-type and GVWR, the manufacturers must certify to the numerically lower standard.

(ii) For a Phase 2 vehicle model that includes a range of GVWR values that straddle weight classes, manufacturers may include all the vehicles in the same vehicle family if it certifies the vehicle family to the numerically lower fuel consumption standard from the affected service classes. Vehicles that are optionally certified to a more stringent standard under this paragraph are subject to useful-life and all other provisions corresponding to the weight class with the numerically lower fuel consumption standard. For a Phase 2 tractor model that includes a range of roof heights that straddle subcategories, a manufacturer may include all the vehicles in the same vehicle family if it certifies the vehicle family to the appropriate subcategory as follows:

(A) A manufacturer may certify mid-roof tractors as high-roof tractors, but it may not certify high-roof tractors as mid-roof tractors.

(B) For tractor families straddling the low-roof/mid-roof division, a manufacturer may certify the family based on the primary roof-height as long as no more than 10 percent of the tractors are certified to the otherwise inapplicable subcategory. For example, if 95 percent of the tractors in the family are less than 120 inches tall, and the other 5 percent are 122 inches tall, a manufacturer may certify the tractors as a single family in the low-roof subcategory.

(C) Determine the appropriate aerodynamic bin number based on the actual roof height if the CdA value is measured. However, use the GEM input for the bin based on the standards to which the manufacturer certifies. For example, of a manufacturer certifies as mid roof tractors some low-roof tractors with a measured CdA value of 4.2 m2, it qualifies as Bin IV; and must input into GEM the mid-roof Bin IV value of 5.85 m2.

(9) *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. For Phase 1, 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. No production limit applies for vocational tractors subject to Phase 2 standards.

(10) *Small business manufacturers converting to mid roof or high roof configurations.* Small manufacturers are to allowed convert low and mid roof tractors to high roof configurations without recertification, provided it is for the purpose of building a custom sleeper tractor or conversion to a natural gas tractor as specified in 40 CFR 1037.150(r).

(11) *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 vehicles at or below 33,000 pounds GVWR.

(ii) 435,000 miles or 10 years, whichever comes first, for vehicles above 33,000 pounds GVWR.

(12) *Conversion to high-roof configurations.* Secondary vehicle manufacturers that qualify as small manufacturers may convert low- and mid-roof tractors to high-roof configurations without recertification for the purpose of building a custom sleeper tractor or converting it to run on natural gas, as follows:

(i) The original low- or mid-roof tractor must be covered by a valid certificate of conformity by EPA.

(ii) The modifications may not increase the frontal area of the tractor beyond the frontal area of the equivalent high-roof tractor with the corresponding standard trailer. If a manufacturer cannot use the original manufacturer's roof fairing for the high-roof tractor, use good engineering judgment to achieve similar or better aerodynamic performance.

(iii) The agencies may require that these manufacturers submit annual production reports as described in § 535.8 and 40 CFR 1037.250 indicating the original roof height for requalified vehicles.

(13) *Compliance with standards.* A manufacturer complies with the standards of this part as described in § 535.10.

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

(1) *Mandatory standards.* Manufacturers of heavy-duty engine families 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 engine families 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. Fuel consumption standards apply each model year to the same engine families used to comply with EPAstandards in 40 CFR 1036.108 and 40 CFR 1037.230. An engine family is designated under the EPA program based upon testing specified in 40 CFR part 1036, subpart F, and the engine family's primary intended service class. Each engine family 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.

(2) *Voluntary compliance.*

(i) For model years 2013 through 2016 for compression-ignition engine families, and for model year 2015 for spark-ignition engine families, a manufacturer may choose voluntarily to comply with the fuel consumption standards provided in paragraphs (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 § 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 engine families are given in the following table:

| Phase 1—Voluntary Standards |
| --- |
| Regulatory subcategory | CI LHD engines and all otherengines | CI MHD engines and all other engines | HHD CI engines and all other engines | SI engines |
| Application | Vocational | Vocational | Tractor | Vocational | Tractor | All |
| 2015 | | | | | | 7.0552 |
| 2013 through 2016 | 5.8939 | 5.8939 | 4.9312 | 5.5697 | 4.666 | |

Table 13 to Paragraph (d)(3)—Primary Heavy-Duty Engine Fuel Consumption Standards

[Gallons per 100 hp-hr]

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

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

(4) *Alternate subcategory standards.* The alternative fuel consumption standards for heavy-duty compression-ignition engine families 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 § 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 engine families 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 engine families certified to these standards are not eligible for early credits under § 535.7.

| Tractors | LHD engines | MHD engines | HHD engines |
| --- | --- | --- | --- |
| Model Years 2013 to 2015 | NA | 5.0295 | 4.7642 |
| Model Years 2016 to 2020 † | 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 † | 5.6582 | 5.6582 | 5.4519 |
| † **Note:** These alternate standards for 2016 and later are the same as the otherwise applicable standards for 2017 through 2020. |

Table 14—Phase 1 Alternative Phase-In CI Engine Fuel Consumption Standards

[Gallons per 100 hp-hr]

(6) *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.

(7) *Optional certification under this section.* Manufacturers certifying spark-ignition engines to the compression-ignition standards for EPA must treat those engines as compression-ignition engines for all the provisions of this part.

(8) *Advanced, innovative and off-cycle technologies.* For engines subject to Phase 1 standards, manufacturers must create separate engine families for engines that contain advanced or innovative technologies and group those engines together in an engine family if they use the same advanced or innovative technologies. Manufacturers may generate separate credit allowances for advanced and innovative technologies as specified in § 535.7(f)(1) and (2). For engines subject to Phase 2 standards, manufacturers may generate separate credits allowance for off-cycle technologies in accordance with § 535.7(f)(2). Credit incentives for advanced technology engines do not apply during the Phase 2 period.

(9) *Useful life.* The exhaust emission standards of this section apply for the full useful life, expressed in service miles, operating hours, or calendar years, whichever comes first. The following useful life values apply for the standards of this section:

(i) 120,000 miles or 11 years, whichever comes first, for CI and SI LHD engines certified to Phase 1 standards.

(ii) 150,000 miles or 15 years, whichever comes first, for CI and SI LHD and spark-ignition engines certified to Phase 2 standards.

(iii) 185,000 miles or 10 years, whichever comes first, for CI MHD engines certified to Phase 1 and for Phase 2.

(iv) 435,000 miles or 10 years, whichever comes first, for CI HHD engines certified to Phase 1 and for Phase 2.

(v) For Phase 1 credits that manufacturers calculate based on a useful life of 110,000 miles, multiply any banked credits that it carries forward for use into the Phase 2 program by 1.36. For Phase 1 credit deficits that manufacturers 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.

(10) *Loose engines.* This paragraph (10) describes alternate emission and fuel consumption standards for loose engines certified under. The standards of this paragraph (d) and 1036.108 do not apply for loose engines certified under paragraph (a) of this section and 40 CFR 86.1819-14(k)(8). The standards in 40 CFR 1036.150(j) apply for the emissions and equivalent fuel consumption measured with the engine installed in a complete vehicle consistent with the provisions of 40 CFR 86.1819-14(k)(8)(vi).

(11) *Alternate transition option for Phase 2 engine standards.*

(i) Manufacturers may optionally elect to comply with the model year 2021 primary (Phase 2) vocational vehicle and tractor engine standards in paragraph (d)(3) of this section beginning in model year 2020 (*e.g.* comply with the more stringent standards one year early). The model year 2021 standard would apply to these manufacturers for model years 2020 through 2023. Manufacturers that voluntarily certify their engines to model year 2021 standards early would then be eligible for less stringent engine tractor standards in model years 2024 through 2026, as follows:

(A) 5.3241 gallons per 100 hp-hr for MHD vocational vehicle engines.

(B) 4.5874 gallons per 100 hp-hr for MHD tractor engines.

(C) 5.0098 gallons per 100 hp-hr for HHD vocational vehicle engines.

(D) 4.3418 gallons per 100 hp-hr for HHD tractor engines.

(ii) The primary standard in paragraph (d)(3) applies for all manufacturers in model year 2027 and later years.

(iii) Manufacturers may apply these provisions separately for medium heavy-duty engines and heavy heavy-duty engines. This election applies to all engines in each segment. For example, if a manufacturer elects this alternate option for its medium heavy-duty engines, all of the manufacturer's medium heavy-duty vocational and tractor engines must comply. Engine fuel consumption credits generated under § 535.7(d) for manufacturers complying early with the model year 2021 standards follow the temporary extended credit life allowance in § 535.7(d)(9).

(12) *Compliance with Standards.* A manufacturer complies with the standards of this part as described in § 535.10.

[81 FR 74238, Oct. 25, 2016, as amended at 89 FR 18819, Mar. 15, 2024; 89 FR 52951, June 24, 2024]