(a) The standards of this section apply for the following vehicles:

(1) Heavy-duty vehicles at or below 14,000 pounds GVWR that are not subject to the greenhouse gas standards in 40 CFR part 86, subpart S, or that use engines certified under § 1037.150(m).

(2) Vehicles above 14,000 pounds GVWR and at or below 26,000 pounds GVWR, but not certified to the vehicle greenhouse gas standards in 40 CFR part 86, subpart S.

(3) Vehicles above 26,000 pounds GVWR that are not tractors.

(4) Vocational tractors.

(b) CO2 standards in this paragraph (b) apply based on modeling and testing as specified in subpart F of this part. The provisions of § 1037.241 specify how to comply with the standards in this paragraph (b). Standards differ based on engine cycle, vehicle size, and intended vehicle duty cycle. See § 1037.510(c) to determine which duty cycle applies. Note that § 1037.230 describes how to divide vehicles into subcategories.

(1) Except as specified in paragraph (b)(2) of this section, model year 2027 and later vehicles are subject to Phase 3 CO2 standards corresponding to the selected subcategories as shown in the following table:

(2) Qualifying small manufacturers of model year 2027 and later vehicles may continue to meet Phase 2 CO2 standards in this paragraph (b)(2) instead of the standards specified in paragraph (b)(1) of this section. If you certify to these Phase 2 CO2 standards, you may use the averaging provisions of subpart H of this part to demonstrate compliance. You may use other credit provisions of this part only by certifying all vehicle families within a given averaging set to the Phase 3 standards that apply in that model year.

(3) Model year 2024 through 2026 vehicles are subject to Phase 2 CO2 standards corresponding to the selected subcategories as shown in the following table:

(4) Model year 2021 through 2023 vehicles are subject to Phase 2 CO2 standards corresponding to the selected subcategories as shown in the following table:

(5) Model year 2014 through 2020 vehicles are subject to Phase 1 CO2 standards as shown in the following table:

(c) [Reserved]

(d) You may generate or use emission credits for averaging, banking, and trading to demonstrate compliance with the standards in paragraph (b) of this section as described in subpart H of this part. This requires that you specify a Family Emission Limit (FEL) for CO2 for each vehicle subfamily. The FEL may not be less than the result of emission modeling from § 1037.520. These FELs serve as the emission standards for the vehicle subfamily instead of the standards specified in paragraph (b) of this section.

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

(1) 150,000 miles or 15 years, whichever comes first, for Light HDV.

(2) 185,000 miles or 10 years, whichever comes first, for Medium HDV.

(3) 435,000 miles or 10 years, whichever comes first, for Heavy HDV.

(f) See § 1037.631 for provisions that exempt certain vehicles used in off-road operation from the standards of this section.

(g) You may optionally certify a vocational vehicle to the standards and useful life applicable to a heavier vehicle service class (such as Medium HDV instead of Light HDV). Provisions related to generating emission credits apply as follows:

(1) If you certify all your 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, you may generate credits as appropriate for the heavier service class.

(2) Class 8 hybrid vehicles with Light HDE or Medium HDE may be certified to compression-ignition standards for the Heavy HDV service class. You may generate and use credits as allowed for the Heavy HDV service class.

(3) Except as specified in paragraphs (g)(1) and (2) of this section, you 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 you include lighter vehicles in a subfamily with an FEL above the standard, you must include the production volume of lighter vehicles in the credit calculation.

(h) You may optionally certify certain vocational vehicles to alternative standards as specified in this paragraph (h) instead of the standards specified in paragraph (b) of this section. You may apply the provisions in this paragraph (h) to any qualifying vehicles 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 specified in § 1037.140(g)(7); however, standards apply for the vehicle's useful life based on its actual characteristics as specified in paragraph (e) of this section. Vehicles certified to the standards in this paragraph (h) must include the following statement on the emission control label: “THIS VEHICLE WAS CERTIFIED AS A [identify vehicle type as identified in this section] UNDER 40 CFR 1037.105(h)].” These custom-chassis provisions apply as follows:

(1) The following alternative emission standards apply by vehicle type and model year as follows:

(i) Except as specified in paragraph (h)(1)(ii) of this section, CO2 standards apply for model year 2021 and later custom-chassis vehicles as shown in the following tables:

(ii) For qualifying small manufacturers, Phase 2 CO2 standards apply for model year 2027 and later custom-chassis vehicles instead of the standards specified in paragraph (h)(1)(i) of this section.

(iii) Vehicle types identified in this paragraph (h)(1) are generally defined in § 1037.801. “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 § 1037.631(a)(1) or (2).

(2) You may generate or use emission credits for averaging to demonstrate compliance with the alternative standards as described in subpart H of this part. This requires that you specify a Family Emission Limit (FEL) for CO2 for each vehicle subfamily. The FEL may not be less than the result of emission modeling as described in § 1037.520. These FELs serve as the emission standards for the vehicle subfamily instead of the standards specified in this paragraph (h). Calculate credits using the equation in § 1037.705(b) with the standard payload for the assigned vehicle service class and the useful life identified in paragraph (e) of this section. Each separate vehicle type identified in paragraph (h)(1) of this section (or group of vehicle types identified in a single row) represents a separate averaging set. You may not use averaging for vehicles meeting standards under paragraphs (h)(5) through (7) of this section, and you may not bank or trade emission credits from any vehicles certified under this paragraph (h).

(3) [Reserved]

(4) For purposes of emission modeling under § 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.

(5) Emergency vehicles are deemed to comply with the standards of this paragraph (h) if they use tires with TRRL at or below 8.4 N/kN (8.7 N/kN for model years 2021 through 2026).

(6) Concrete mixers and mixed-use vehicles are deemed to comply with the standards of this paragraph (h) if they use tires with TRRL at or below 7.1 N/kN (7.6 N/kN for model years 2021 through 2026).

(7) Motor homes are deemed to comply with the standards of this paragraph (h) if they have tires with TRRL at or below 6.0 N/kN (6.7 N/kN for model years 2021 through 2026) and automatic tire inflation systems or tire pressure monitoring systems with wheels on all axles.

(8) Vehicles certified to standards under this paragraph (h) must use engines certified under 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 § 1037.150(m). This paragraph (h)(8) also applies for vehicles meeting standards under paragraphs (h)(5) through (7) of this section.