This section describes exhaust emission standards for CO2, CH4, and N2O for medium-duty vehicles. The standards of this section apply for model year 2014 and later vehicles that are chassis-certified with respect to criteria pollutants under this subpart S. Additional medium-duty and heavy-duty vehicles may be subject to the standards of this section as specified in paragraph (j) of this section. Any medium-duty or heavy-duty vehicles not subject to standards under this section are instead subject to greenhouse gas standards under 40 CFR part 1037, and engines installed in these vehicles are subject to standards under 40 CFR part 1036. If you are not the engine manufacturer, you must notify the engine manufacturer that its engines are subject to 40 CFR part 1036 if you intend to use their engines in vehicles that are not subject to standards under this section. Vehicles produced by small businesses may be exempted from the standards of this section as described in paragraph (k)(5) of this section.

(a) Fleet-average CO2 emission standards. Fleet-average CO2 emission standards apply for the full useful life for each manufacturer as follows:

(1) Calculate a work factor, WF, for each vehicle subconfiguration (or group of subconfigurations as allowed under paragraph (a)(4) of this section), rounded to the nearest pound, using the following equation:

WF = 0.75 × (GVWR − Curb Weight + xwd) + 0.25 × (GCWR − GVWR)

Where: xwd = 500 pounds if the vehicle has four-wheel drive or all-wheel drive; xwd = 0 pounds for all other vehicles.

(2) CO2 target values apply as described in this paragraph (a)(2) for model year 2032 and later. See paragraph (k)(4) of this section for model year 2031 and earlier:

(i) For vehicles with work factor at or below 5,500 pounds, use the appropriate work factor in the following equation to calculate a target value for each vehicle subconfiguration (or group of subconfigurations as allowed under paragraph (a)(4) of this section), rounding to the nearest whole g/mile:

CO2 Target = 0.0221 × WF + 170

(ii) For vehicles with work factor above 5,500 pounds, the CO2 target value is 292 g/mile.

(3) Calculate a production-weighted average of the target values and round it to the nearest whole g/mile. This is your fleet-average standard. All vehicles subject to the standards of this section form a single averaging set. Use the following equation to calculate your fleet-average standard from the target value for each vehicle subconfiguration (Targeti) and U.S.-directed production volume of each vehicle subconfiguration for the given model year (Volumei):

(4) You may group subconfigurations within a configuration together for purposes of calculating your fleet-average standard as follows:

(i) You may group together subconfigurations that have the same equivalent test weight (ETW), GVWR, and GCWR. Calculate your work factor and target value assuming a curb weight equal to two times ETW minus GVWR.

(ii) You may group together other subconfigurations if you use the lowest target value calculated for any of the subconfigurations.

(5) The standards specified in this section apply for testing at both low-altitude conditions and high-altitude conditions. However, manufacturers must submit an engineering evaluation indicating that common calibration approaches are utilized at high altitude instead of performing testing for certification, consistent with § 86.1829. Any deviation from low altitude emission control practices must be included in the auxiliary emission control device (AECD) descriptions submitted at certification. Any AECD specific to high altitude requires engineering emission data for EPA evaluation to quantify any emission impact and determine the validity of the AECD.

(b) Production and in-use CO2 standards. Each vehicle you produce that is subject to the standards of this section has an “in-use” CO2 standard that is calculated from your test result and that applies for selective enforcement audits and in-use testing. This in-use CO2 standard for each vehicle is equal to the applicable deteriorated emission level multiplied by 1.10 and rounded to the nearest whole g/mile.

(c) N2O and CH4 standards. Except as allowed under this paragraph (c), all vehicles subject to the standards of this section must comply with an N2O standard of 0.05 g/mile and a CH4 standard of 0.05 g/mile when calculated according to the provisions of paragraph (d)(4) of this section. You may specify CH4 and/or N2O alternative standards using CO2 emission credits instead of these otherwise applicable emission standards for one or more test groups. To do this, calculate the CH4 and/or N2O emission credits needed (negative credits) using the equation in this paragraph (c) based on the FEL(s) you specify for your vehicles during certification. You must adjust the calculated emissions by the global warming potential (GWP): GWP equals 34 for CH4 from model year 2021 and later vehicles, 25 for CH4 from earlier vehicles, and 298 for N2O. This means, for example, that you must use 298 Mg of positive CO2 credits to offset 1 Mg of negative N2O credits. Note that § 86.1818-12(f) does not apply for vehicles subject to the standards of this section. Calculate credits using the following equation, rounded to the nearest whole number:

CO2 Credits Needed (Mg) = [(FEL − Std) × (U.S.-directed production volume) × (Useful Life)] × (GWP) ÷ 1,000,000

(d) Compliance provisions. The following compliance provisions apply instead of other provisions described in this subpart S:

(1) The CO2 standards of this section apply with respect to CO2 emissions, not with respect to carbon-related exhaust emissions (CREE).

(2) The following general credit provisions apply:

(i) Except as specified in paragraph (d)(2)(iv) of this section, credits you generate under this section may be used only to offset credit deficits under this section. You may bank credits for use in a future model year in which your average CO2 level exceeds the standard. You may trade credits to another manufacturer according to § 86.1865-12(k)(8). Before you bank or trade credits, you must apply any available credits to offset a deficit if the deadline to offset that credit deficit has not yet passed.

(ii) Vehicles subject to the standards of this section are included in a single greenhouse gas averaging set separate from any averaging set otherwise included in this subpart S.

(iii) Banked CO2 credits keep their full value for five model years after the year in which they were generated. Unused credits may not be used for more than five model years after the model year in which the credits are generated.

(iv) Credits generated under this section may be used to demonstrate to compliance with the CO2 emission standards for vehicles certified under 40 CFR part 1037 as described in 40 CFR 1037.150(z).

(3) Special credit and incentive provisions related to air conditioning in §§ 86.1867 and 86.1868 do not apply for vehicles subject to the standards of this section.

(4) Measure emissions using the procedures of subpart B of this part and 40 CFR part 1066. Determine separate emission results for the Federal Test Procedure (FTP) described in 40 CFR 1066.801(c)(1) and the Highway Fuel Economy Test (HFET) described in 40 CFR 1066.801(c)(3). Calculate composite emission results from these two test cycles for demonstrating compliance with the CO2, N2O, and CH4 standards based on a weighted average of the FTP (55%) and HFET (45%) emission results. Note that this differs from the way the criteria pollutant standards apply.

(5) Apply an additive deterioration factor of zero to measured CO2 emissions unless good engineering judgment indicates that emissions are likely to deteriorate in use. Use good engineering judgment to develop separate deterioration factors for N2O and CH4.

(6) Credits are calculated using the useful life value (in miles) in place of “vehicle lifetime miles” as specified in § 86.1865. Calculate a total credit or debit balance in a model year by adding credits and debits from § 86.1865-12(k)(4), subtracting any CO2-equivalent debits for N2O or CH4 calculated according to paragraph (c) of this section, and adding any of the following credits:

(i) Off-cycle technology credits according to paragraph (d)(13) of this section.

(ii) Early credits from vehicles certified under paragraph (k)(2) of this section.

(iii) Advanced-technology credits according to paragraph (k)(7) of this section.

(7) [Reserved]

(8) The provisions of § 86.1818 do not apply.

(9) Calculate your fleet-average emission rate consistent with good engineering judgment and the provisions of § 86.1865. The following additional provisions apply:

(i) Unless we approve a lower number, you must test at least ten subconfigurations. If you produce more than 100 subconfigurations in a given model year, you must test at least ten percent of your subconfigurations. For purposes of this paragraph (d)(9)(i), count carryover tests, but do not include analytically derived CO2 emission rates, data substitutions, or other untested allowances. We may approve a lower number of tests for manufacturers that have limited product offerings, or low sales volumes. Note that good engineering judgment and other provisions of this part may require you to test more subconfigurations than these minimum values.

(ii) The provisions of paragraph (g) of this section specify how you may use analytically derived CO2 emission rates.

(iii) At least 90 percent of final production volume at the configuration level must be represented by test data (real, data substituted, or analytical).

(iv) Perform fleet-average CO2 calculations as described in § 86.1865 and 40 CFR part 600, with the following exceptions:

(A) Use CO2 emissions values for all test results, intermediate calculations, and fleet average calculations instead of the carbon-related exhaust emission (CREE) values specified in this subpart S and 40 CFR part 600.

(B) Perform intermediate CO2 calculations for subconfigurations within each configuration using the subconfiguration and configuration definitions in paragraph (d)(12) of this section.

(C) Perform intermediate CO2 calculations for configurations within each test group and transmission type (instead of configurations within each base level and base levels within each model type). Use the configuration definition in paragraph (d)(12)(i) of this section.

(D) Do not perform intermediate CO2 calculations for each base level or for each model type. Base level and model type CO2 calculations are not applicable to heavy-duty vehicles subject to standards in this section.

(E) Determine fleet average CO2 emissions for heavy-duty vehicles subject to standards in this section as described in 40 CFR 600.510-12(j), except that the calculations must be performed on the basis of test group and transmission type (instead of the model-type basis specified in the light-duty vehicle regulations), and the calculations for dual-fuel, multi-fuel, and flexible-fuel vehicles must be consistent with the provisions of paragraph (d)(10)(i) of this section.

(10) For dual-fuel, multi-fuel, and flexible-fuel vehicles, perform exhaust testing on each fuel type (for example, gasoline and E85).

(i) Use either the conventional-fueled CO2 emission rate or a weighted average of your emission results as specified in 40 CFR 600.510-12(k) for light-duty trucks.

(ii) If you certify to an alternate standard for N2O or CH4 emissions, you may not exceed the alternate standard when tested on either fuel.

(11) Test your vehicles with an equivalent test weight based on its Adjusted Loaded Vehicle Weight (ALVW). Determine equivalent test weight from the ALVW as specified in 40 CFR 1066.805; round ALVW values above 14,000 pounds to the nearest 500 pound increment.

(12) The following definitions apply for the purposes of this section:

(i) Configuration means a subclassification within a test group based on engine code, transmission type and gear ratios, final drive ratio, and other parameters we designate. Engine code means the combination of both “engine code” and “basic engine” as defined for light-duty vehicles in 40 CFR 600.002.

(ii) Subconfiguration means a unique combination within a vehicle configuration (as defined in this paragraph (d)(12)) of equivalent test weight, road-load horsepower, and any other operational characteristics or parameters that we determine may significantly affect CO2 emissions within a vehicle configuration. Note that for vehicles subject to standards of this section, equivalent test weight (ETW) is based on the ALVW of the vehicle as outlined in paragraph (d)(11) of this section.

(13) This paragraph (d)(13) applies for CO2 reductions resulting from technologies that were not in common use before 2010 that are not reflected in the specified test procedures. While you are not required to prove that such technologies were not in common use with heavy-duty vehicles before model year 2010, we will not approve your request if we determine they do not qualify. These may be described as off-cycle or innovative technologies. We may allow you to generate emission credits consistent with the provisions of § 86.1869-12(c) and (d), but only through model year 2026. The 5-cycle methodology is not presumed to be preferred over alternative methodologies described in § 86.1869-12(d).

(14) You must submit pre-model year reports before you submit your applications for certification for a given model year. Unless we specify otherwise, include the information specified for pre-model year reports in 49 CFR 535.8.

(15) You must submit a final report within 90 days after the end of the model year. Unless we specify otherwise, include applicable information identified in § 86.1865-12(l), 40 CFR 600.512, and 49 CFR 535.8(e). The final report must include at least the following information:

(i) Model year.

(ii) Applicable fleet average CO2 standard.

(iii) Calculated fleet average CO2 value and all the values required to calculate the CO2 value.

(iv) Number of credits or debits incurred and all values required to calculate those values.

(v) Resulting balance of credits or debits.

(vi) N2O emissions.

(vii) CH4 emissions.

(viii) Total and percent leakage rates under paragraph (h) of this section (through model year 2026 only).

(16) You may apply the provisions for delegated assembly as described in 40 CFR 1037.621.

(17) You may calculate emission rates for weight increments less than the 500-pound increment specified for test weight. This does not change the applicable test weights.

(i) Use the ADC equation in paragraph (g) of this section to adjust your emission rates for vehicles in increments of 50, 100, or 250 pounds instead of the 500 pound test-weight increments. Adjust emissions to the midpoint of each increment. This is the equivalent emission weight. For example, vehicles with a test weight basis of 11,751 to 12,250 pounds (which have an equivalent test weight of 12,000 pounds) could be regrouped into 100-pound increments as follows:

(ii) You must use the same increment for all equivalent test weight classes across your whole product line in a given model year. You must also specify curb weight for calculating the work factor in a way that is consistent with your approach for determining test weight for calculating ADCs under this paragraph (d)(17).

(e) Useful life. The exhaust emission standards of this section apply for the full useful life, as described in § 86.1805.

(f) [Reserved]

(g) Analytically derived CO2 emission rates (ADCs). This paragraph (g) describes an allowance to use estimated (i.e., analytically derived) CO2 emission rates based on baseline test data instead of measured emission rates for calculating fleet-average emissions. Note that these ADCs are similar to ADFEs used for light-duty vehicles. Note also that F terms used in this paragraph (g) represent coefficients from the following road load equation:

Force = F0 + F1 · (velocity) + F2 · (velocity) 2

(1) Except as specified in paragraph (g)(2) of this section, use the following equation to calculate the ADC of a new vehicle from road load force coefficients (F0, F1, F2), axle ratio, and test weight:

ADC = CO2base + 2.18 · ΔF0 + 37.4 · ΔF1 + 2257 · ΔF2 + 189 · ΔAR + 0.0222· ΔETW Where: ADC = Analytically derived combined city/highway CO2 emission rate (g/mile) for a new vehicle. CO2base = Combined city/highway CO2 emission rate (g/mile) of a baseline vehicle. ΔF0 = F0 of the new vehicle−F0 of the baseline vehicle. ΔF1 = F1 of the new vehicle−F1 of the baseline vehicle. ΔF2 = F2 of the new vehicle−F2 of the baseline vehicle. ΔAR = Axle ratio of the new vehicle−axle ratio of the baseline vehicle. ΔETW = ETW of the new vehicle−ETW of the baseline vehicle.

(2) The purpose of this section is to accurately estimate CO2 emission rates.

(i) You must apply the provisions of this section consistent with good engineering judgment. For example, do not use the equation in paragraph (g)(1) of this section where good engineering judgment indicates that it will not accurately estimate emissions. You may ask us to approve alternate equations that allow you to estimate emissions more accurately.

(ii) The analytically derived CO2 equation in paragraph (g)(1) of this section may be periodically updated through publication of an EPA guidance document to more accurately characterize CO2 emission levels for example, changes may be appropriate based on new test data, future technology changes, or to changes in future CO2 emission levels. Any EPA guidance document will determine the model year that the updated equation takes effect. We will issue guidance no later than eight months before the effective model year. For example, model year 2014 may start January 2, 2013, so guidance for model year 2014 would be issued by May 1, 2012.

(3) You may select baseline test data without our advance approval if they meet all the following criteria:

(i) Vehicles considered for the baseline test must comply with all applicable emission standards in the model year associated with the ADC.

(ii) You must include in the pool of tests considered for baseline selection all official tests of the same or equivalent basic engine, transmission class, engine code, transmission code, engine horsepower, dynamometer drive wheels, and compression ratio as the ADC subconfiguration. Do not include tests in which emissions exceed any applicable standard.

(iii) Where necessary to minimize the CO2 adjustment, you may supplement the pool with tests associated with worst-case engine or transmission codes and carryover or carry-across test groups. If you do, all the data that qualify for inclusion using the elected worst-case substitution (or carryover or carry-across) must be included in the pool as supplemental data (i.e., individual test vehicles may not be selected for inclusion). You must also include the supplemental data in all subsequent pools, where applicable.

(iv) Tests previously used during the subject model year as baseline tests in ten other ADC subconfigurations must be eliminated from the pool.

(v) Select the tested subconfiguration with the smallest absolute difference between the ADC and the test CO2 emission rate for combined emissions. Use this as the baseline test for the target ADC subconfiguration.

(4) You may ask us to allow you to use baseline test data not fully meeting the provisions of paragraph (g)(3) of this section.

(5) Calculate the ADC rounded to the nearest whole g/mile. Except with our advance approval, the downward adjustment of ADC from the baseline is limited to ADC values 20 percent below the baseline emission rate. The upward adjustment is not limited.

(6) You may not submit an ADC if an actual test has been run on the target subconfiguration during the certification process or on a development vehicle that is eligible to be declared as an emission-data vehicle.

(7) No more than 40 percent of the subconfigurations tested in your final CO2 submission may be represented by ADCs.

(8) Keep the following records for at least five years, and show them to us if we ask to see them:

(i) The pool of tests.

(ii) The vehicle description and tests chosen as the baseline and the basis for the selection.

(iii) The target ADC subconfiguration.

(iv) The calculated emission rates.

(9) We may perform or order a confirmatory test of any subconfiguration covered by an ADC.

(10) Where we determine that you did not fully comply with the provisions of this paragraph (g), we may require that you comply based on actual test data and that you recalculate your fleet-average emission rate.

(h) Air conditioning leakage. Loss of refrigerant from your air conditioning systems may not exceed a total leakage rate of 11.0 grams per year or a percent leakage rate of 1.50 percent per year, whichever is greater. This applies for all refrigerants. Calculate the annual rate of refrigerant leakage according to the procedures specified in SAE J2727 SEP2023 (incorporated by reference, see § 86.1) or as specified in § 86.1867-12(a). Calculate the percent leakage rate as: [total leakage rate (g/yr)] ÷ [total refrigerant capacity (g)] × 100. Round your percent leakage rate to the nearest one-hundredth of a percent. For purpose of this requirement, “refrigerant capacity” is the total mass of refrigerant recommended by the vehicle manufacturer as representing a full charge. Where full charge is specified as a pressure, use good engineering judgment to convert the pressure and system volume to a mass.

(i) [Reserved]

(j) GHG certification of additional vehicles under this subpart. You may certify certain complete or cab-complete vehicles to the GHG standards of this section. Certain high-GCWR vehicles may also be subject to the GHG standards of this section. All vehicles optionally certified under this paragraph (j) are deemed to be subject to the GHG standards of this section. Note that for vehicles above 14,000 pounds GVWR and at or below 26,000 pounds GVWR, GHG certification under this paragraph (j) does not affect how you may or may not certify with respect to criteria pollutants.

(1) For GHG compliance, you 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 GHG standards of this section even though this section otherwise specifies that you may certify vehicles to the GHG standards of this section only if they are chassis-certified for criteria pollutants. This paragraph (j)(1) also applies for vehicles at or below 14,000 pounds GVWR with GCWR above 22,000 pounds with installed engines that have been certified under 40 CFR part 1036 as described in 40 CFR 1036.635.

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

(i) Except as specified in paragraph (j)(3) 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. You may not apply the provisions of this paragraph (j) to any vehicle configuration that has a four-wheel rear axle if the complete sister vehicle has a two-wheel rear axle.

(ii) Calculate the target value for fleet average CO2 emissions under paragraph (a) or (k)(4) of this section based on the work factor value that applies for the complete sister vehicle.

(iii) 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 GHG certification, you may submit the test data from that complete sister vehicle instead of performing the test on the cab-complete vehicle.

(iv) You are not required to produce the complete sister vehicle for sale to use the provisions of this paragraph (j)(2). 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.

(3) For GHG 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, you may use the road-load coefficients from the complete sister vehicle for certification testing of the cab-complete vehicle, but you may not use emission data from the complete sister vehicle for certifying the cab-complete vehicle.

(4) The GHG standards of this section and related provisions apply for vehicles above 22,000 pounds GCWR as described in 40 CFR 1036.635.

(k) Interim provisions. The following provisions apply instead of other provisions in this subpart:

(1) Incentives for early introduction. Manufacturers may voluntarily certify in model year 2013 (or earlier model years for electric vehicles) to the greenhouse gas standards that apply starting in model year 2014 as specified in 40 CFR 1037.150(a).

(2) Early credits. To generate early credits under this paragraph (k)(2) for any vehicles other than electric vehicles, you must certify your entire U.S.-directed fleet to these standards. If you calculate a separate fleet average for advanced-technology vehicles under paragraph (k)(7) of this section, you must certify your entire U.S.-directed production volume of both advanced and conventional vehicles within the fleet. If some test groups are certified after the start of the model year, you may generate credits only for production that occurs after all test groups are certified. For example, if you produce three test groups in an averaging set and you receive your certificates for those test groups on January 4, 2013, March 15, 2013, and April 24, 2013, you may not generate credits for model year 2013 for vehicles from any of the test groups produced before April 24, 2013. Calculate credits relative to the standard that would apply in model year 2014 using the applicable equations in this subpart and your model year 2013 U.S.-directed production volumes. These credits may be used to show compliance with the standards of this subpart for 2014 and later model years. We recommend that you notify us of your intent to use this provision before submitting your applications.

(3) Compliance date. Compliance with the standards of this section was optional before January 1, 2014 as specified in 40 CFR 1037.150(g).

(4) Historical and interim standards. The following CO2 target values apply for model year 2031 and earlier vehicles:

(i) CO2 target values apply as follows for model years 2014 through 2027, except as specified in paragraph (k)(4)(ii) of this section:

(ii) The following optional alternative CO2 target values apply for model years 2014 through 2020:

(iii) CO2 target values apply as follows for all engine types for model years 2028 through 2031:

(5) Provisions for small manufacturers. Standards apply on a delayed schedule for manufacturers meeting the small business criteria specified in 13 CFR 121.201 (NAICS code 336111); the employee and revenue limits apply to the total number employees and total revenue together for affiliated companies. Qualifying small manufacturers are not subject to the greenhouse gas standards of this section for vehicles with a date of manufacture before January 1, 2022, as specified in 40 CFR 1037.150(c). In addition, small manufacturers producing vehicles that run on any fuel other than gasoline, E85, or diesel fuel may delay complying with every later standard under this part by one model year through model year 2026. The following provisions apply starting with model year 2027:

(i) Qualifying small manufacturers remain subject to the model year 2026 greenhouse gas standards; however, small manufacturers may trade emission credits generated in a given model year only by certifying to standards that apply for that model year.

(ii) Small manufacturers may produce no more than 500 exempt vehicles in any model year under paragraph (k)(5)(i) of this section. This limit applies for vehicles with engines, including plug-in hybrid electric vehicles; this limit does not apply for electric vehicles. Vehicles that are not exempt under this paragraph (k)(5) must meet emission standards as specified in this section.

(6) Alternate N2O standards. Manufacturers may show compliance with the N2O standards using an engineering analysis. This allowance also applies for model year 2015 and later test groups carried over from model 2014 consistent with the provisions of § 86.1839. You may not certify to an N2O FEL different than the standard without measuring N2O emissions.

(7) Advanced-technology credits. Provisions for advanced-technology credits apply as described in 40 CFR 1037.615. If you generate credits from Phase 1 vehicles certified with advanced technology (in model years 2014 through 2020), you may multiply these credits by 1.50. If you generate credits from model year 2021 through 2026 vehicles certified with advanced technology, you may multiply these credits by 3.5 for plug-in hybrid electric vehicles, 4.5 for battery electric vehicles, and 5.5 for fuel cell vehicles. Advanced-technology credits from Phase 1 vehicles may be used to show compliance with any standards of this part or 40 CFR part 1036 or part 1037, subject to the restrictions in 40 CFR 1037.740. Similarly, you may use up to 60,000 Mg per year of advanced-technology credits generated under 40 CFR 1036.615 or 1037.615 (from Phase 1 vehicles) to demonstrate compliance with the CO2 standards in this section. Include vehicles generating credits in separate fleet average calculations (and exclude them from your conventional fleet average calculation). You must first apply these advanced-technology vehicle credits to any deficits for other vehicles in the averaging set before applying them to other averaging sets. The provisions of this paragraph (k)(7) do not apply for credits generated from model year 2027 and later vehicles.

(8) Loose engine sales. This paragraph (k)(8) applies 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 you sell such engines as loose engines or as engines installed in incomplete vehicles that are not cab-complete vehicles. You may include such engines in a test group certified to the standards of this section, subject to the following provisions:

(i) Engines certified under this paragraph (k)(8) are deemed to be certified to the standards of 40 CFR 1036.108 as specified in 40 CFR 1036.150(j).

(ii) For 2020 and earlier model years, the maximum allowable U.S.-directed production volume of engines you sell under this paragraph (k)(8) in any given model year is ten percent of the total U.S-directed production volume of engines of that design that you produce for heavy-duty applications for that model year, including engines you produce for complete vehicles, cab-complete vehicles, and other incomplete vehicles. The total number of engines you may certify under this paragraph (k)(8), 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, if you produce 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 you do not apply the provisions of this paragraph (k)(8) to any other engine designs, you may produce up to 10,000 engines of that design for sale as loose engines under this paragraph (k)(8). If you produced 11,000 engines of that design for sale as loose engines, the last 1,000 of them that you produced in that model year 2017 would be considered uncertified.

(iii) For model years 2021 through 2023, the U.S.-directed production volume of engines you sell under this paragraph (k)(8) in any given model year may not exceed 10,000 units.

(iv) This paragraph (k)(8) does not apply for engines certified to the standards of 40 CFR 1036.108.

(v) Label the engines as specified in 40 CFR 1036.135 including the following compliance statement: “THIS ENGINE WAS CERTIFIED TO THE ALTERNATE GREENHOUSE GAS EMISSION STANDARDS OF 40 CFR 1036.150(j).” List the test group name instead of an engine family name.

(vi) Vehicles using engines certified under this paragraph (k)(8) are subject to the emission standards of 40 CFR 1037.105.

(vii) For certification purposes, your engines are deemed to have a CO2 target value and test result equal to the CO2 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 (k)(8)(vii)(B) of this section. Use these values to calculate your target value, fleet average emission rate, and in-use emission standard. Where there are multiple complete vehicles with the same highest equivalent test weight, select the CO2 target value and test result as follows:

(A) If one or more of the CO2 test results exceed the applicable target value, use the CO2 target value and test result of the vehicle that exceeds its target value by the greatest amount.

(B) If none of the CO2 test results exceed the applicable target value, select the highest target value and set the test result equal to it. This means that you may not generate emission credits from vehicles certified under this paragraph (k)(8).

(viii) Production and in-use CO2 standards apply as described in paragraph (b) of this section.

(ix) N2O and CH4 standards apply as described in paragraph (c) of this section.

(x) State in your applications for certification that your test group and engine family will include engines certified under this paragraph (k)(8). This applies for your greenhouse gas vehicle test group and your criteria pollutant engine family. List in each application the name of the corresponding test group/engine family.

(9) Credit adjustment for useful life. For credits that you calculate based on a useful life of 120,000 miles, multiply any banked credits that you carry forward for use in model year 2021 and later by 1.25.

(10) CO2 rounding. For model year 2014 and earlier vehicles, you may round measured and calculated CO2 emission levels to the nearest 0.1 g/mile, instead of the nearest whole g/mile as specified in paragraphs (a), (b), and (g) of this section.

[81 FR 73895, Oct. 25, 2016, as amended at 88 FR 4479, Jan. 24, 2023; 89 FR 28172, Apr. 18, 2024; 89 FR 29738, Apr. 22, 2024]