(a) Engine and vehicle manufacturers, as well as owners and operators of vehicles subject to the requirements of this part, and all other persons, must observe the provisions of this part, the applicable provisions of 40 CFR part 1068, and the applicable provisions of the Clean Air Act. The provisions of 40 CFR part 1068 apply for heavy-duty vehicles as specified in that part, subject to the provisions:

(1) Except as specifically allowed by this part or 40 CFR part 1068, it is a violation of 40 CFR 1068.101(a)(1) to introduce into U.S. commerce either a tractor or vocational vehicle that is not certified to the applicable requirements of this part or a tractor or vocational vehicle containing an engine that is not certified to the applicable requirements of 40 CFR part 86 or 1036. Further, it is a violation to introduce into U.S. commerce a Phase 1 tractor containing an engine not certified for use in tractors; or to introduce into U.S. commerce a vocational vehicle containing a Light HDE or Medium HDE not certified for use in vocational vehicles. These prohibitions apply especially to the vehicle manufacturer. Note that this paragraph (a)(1) allows the use of Heavy heavy-duty tractor engines in vocational vehicles.

(2) The provisions of 40 CFR 1068.105(a) apply for vehicle manufacturers installing engines certified under 40 CFR part 1036 as further limited by this paragraph (a)(2). If new engine emission standards apply in a given model year, you may install normal inventories of engines from the preceding model year under the provisions of 40 CFR 1068.105(a) through March 31 of that year without our approval; you may not install such engines after March 31 of that year unless we approve it in advance. Installing such engines after March 31 without our prior approval is considered to be prohibited stockpiling of engines. In a written request for our approval, you must describe how your circumstances led you and your engine supplier to have normal inventories of engines that were not used up in the specified time frame. We will approve your request for up to three additional months to install engines under this paragraph (a)(2) if we determine that the excess inventory is a result of unforeseeable circumstances and should not be considered circumvention of emission standards. We will limit this approval to a certain number of engines consistent with your normal production and inventory practices. Note that 40 CFR 1068.105(a) allows vehicle manufacturers to use up only normal inventories of engines meeting less stringent standards; if, for example, a vehicle manufacturer's normal practice is to receive a shipment of engines every two weeks, it will deplete its potential to install previous-tier engines under this paragraph (a)(2) well before March 31 in the year that new standards apply.

(3) The exemption provisions of 40 CFR 1068.201 through 1068.230, 1068.240, and 1068.260 through 265 apply for heavy-duty motor vehicles. Other exemption provisions, which are specific to nonroad engines, do not apply for heavy-duty vehicles or heavy-duty engines.

(4) The tampering prohibition in 40 CFR 1068.101(b)(1) applies for alternative fuel conversions as specified in 40 CFR part 85, subpart F.

(5) The warranty-related prohibitions in section 203(a)(4) of the Act (42 U.S.C. 7522(a)(4)) apply to manufacturers of new heavy-duty highway vehicles in addition to the prohibitions described in 40 CFR 1068.101(b)(6). We may assess a civil penalty up to $44,539 for each engine or vehicle in violation. The civil monetary penalty amount listed in this section may not reflect recent inflation adjustments EPA is required to make. The current maximum and minimum statutory civil penalty amounts are located in § 19.4.

(6) A vehicle manufacturer that completes assembly of a vehicle at two or more facilities may ask to use as the date of manufacture for that vehicle the date on which manufacturing is completed at the place of main assembly, consistent with provisions of 49 CFR 567.4. Note that such staged assembly is subject to the corresponding provisions of 40 CFR 1068.260. Include your request in your application for certification, along with a summary of your staged-assembly process. You may ask to apply this allowance to some or all of the vehicles in your vehicle family. Our approval is effective when we grant your certificate. We will not approve your request if we determine that you intend to use this allowance to circumvent the intent of this part.

(7) The provisions for selective enforcement audits apply as described in 40 CFR part 1068, subpart E, and subpart D of this part.

(b) Vehicles exempted from the applicable standards of 40 CFR part 86 or 1036 other than glider vehicles are exempt from the standards of this part without request. Similarly, vehicles other than glider vehicles are exempt without request if the installed engine is exempted from the applicable standards in 40 CFR part 86 or 1036.

(c) The prohibitions of 40 CFR 1068.101 apply for vehicles subject to the requirements of this part. The following specific provisions apply:

(1) The actions prohibited under this provision include introducing into U.S. commerce a complete or incomplete vehicle subject to the standards of this part where the vehicle is not covered by a valid certificate of conformity or exemption.

(2) Applying a Clean Idle sticker to a vehicles with an installed engine that is not certified to the NOX standard of 40 CFR 1036.104(b) violates the prohibition in 40 CFR 1068.101(b)(7)(iii).

(d) The emergency vehicle field modification provisions of 40 CFR 85.1716 apply with respect to the standards of this part.

(e) Under § 1037.801, certain vehicles are considered to be new vehicles when they are imported into the United States, even if they have previously been used outside the country. Independent Commercial Importers may use the provisions of 40 CFR part 85, subpart P, and 40 CFR 85.1706(b) to receive a certificate of conformity for engines and vehicles meeting all the requirements of 40 CFR part 1036 and this part 1037.

(f) Standards apply to multi-fuel vehicles as described for engines in 40 CFR 1036.601(d).

(a) General provisions. This section allows vehicle manufacturers to introduce into U.S. commerce certain new motor vehicles using engines certified to alternate emission standards specified in 40 CFR 1036.605 for motor vehicle engines used in specialty vehicles. You may not install an engine certified to these alternate standards if there is an engine certified to the full set of requirements of 40 CFR part 1036 that has the appropriate physical and performance characteristics to power the vehicle. Note that, although these alternate emission standards are mostly equivalent to standards that apply for nonroad engines under 40 CFR part 1039 or 1048, they are specific to motor vehicle engines. The provisions of this section apply for the following types of specialty vehicles:

(1) All-terrain motor vehicles with portal axles (i.e., axles that are offset from the corresponding wheel centerline by a gear assembly) or any axle configuration involving gear reduction such that the wheels rotate more slowly than the axle.

(2) Amphibious vehicles.

(3) Vehicles with maximum speed at or below 45 miles per hour. If your vehicle is speed-limited to meet this specification by reducing maximum speed below what is otherwise possible, this speed limitation must be programmed into the engine or vehicle's electronic control module in a way that is tamper-proof. If your vehicles are not inherently limited to a maximum speed at or below 45 miles per hour, they may qualify under this paragraph (a)(3) only if we approve your design to limit maximum speed as being tamper-proof in advance.

(4) Through model year 2027, vehicles with a hybrid powertrain in which the engine provides energy only for the Rechargeable Energy Storage System.

(b) Notification and reporting requirements. Send the Designated Compliance Officer written notification describing your plans before using the provisions of this section. In addition, by February 28 of each calendar year (or less often if we tell you), send the Designated Compliance Officer a report with all the following information:

(1) Identify your full corporate name, address, and telephone number.

(2) List the vehicle models for which you used this exemption in the previous year and identify the engine manufacturer and engine model for each vehicle model. Also identify the total number of vehicles produced in the previous year.

(c) Production limits. You may produce up to 1,000 hybrid vehicles in a given model year through model year 2027, and up to 200 of each type of vehicle identified in paragraph (a)(1) through (3) of this section in a given model year. This includes vehicles produced by affiliated companies. If you exceed this limit, the number of vehicles that exceed the limit for the model year will not be covered by a valid certificate of conformity. For the purpose of this paragraph (c), we will count all vehicles labeled or otherwise identified as exempt under this section.

(d) Vehicle standards. The vehicle standards of this part apply as follows for these vehicles:

(1) Vehicles qualifying under paragraphs (a)(1) through (3) of this section are subject to evaporative emission standards of § 1037.103, but are exempt from the other requirements of this part, except as specified in this section and in § 1037.601. These vehicles must include a label as specified in § 1037.135(a) with the information from § 1037.135(c)(1) and (2) and the following statement: “THIS VEHICLE IS EXEMPT FROM GREENHOUSE GAS STANDARDS UNDER 40 CFR 1037.605.”

(2) Hybrid vehicles using the provisions of this section remain subject to the vehicle standards and all other requirements of this part 1037. For example, you may need to use GEM in conjunction with powertrain testing to demonstrate compliance with emission standards under subpart B of this part.

(a) You may ask us to apply the provisions of this section for CO2 emission reductions resulting from vehicle technologies that were not in common use with heavy-duty vehicles before model year 2010 that are not reflected in GEM. 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 that they do not qualify. These may be described as off-cycle or innovative technologies. You may apply these provisions for CO2 emission reductions reflected in the specified test procedures if they are not reflected in GEM, except as allowed under paragraph (g) of this section. We will apply these provisions only for technologies that will result in measurable, demonstrable, and verifiable real-world CO2 emission reductions.

(b) The provisions of this section may be applied as either an improvement factor or as a separate credit, consistent with good engineering judgment. Note that the term “credit” in this section describes an additive adjustment to emission rates and is not equivalent to an emission credit in the ABT program of subpart H of this part. We recommend that you base your credit/adjustment on A to B testing of pairs of vehicles differing only with respect to the technology in question.

(1) Calculate improvement factors as the ratio of in-use emissions with the technology divided by the in-use emissions without the technology. Use the improvement-factor approach where good engineering judgment indicates that the actual benefit will be proportional to emissions measured over the test procedures specified in this part.

(2) Calculate separate credits (g/ton-mile) based on the difference between the in-use emission rate with the technology and the in-use emission rate without the technology. Subtract this value from your GEM result and use this adjusted value to determine your FEL. Use the separate-credit approach where good engineering judgment indicates that the actual benefit will not be proportional to emissions measured over the test procedures specified in this part.

(3) We may require you to discount or otherwise adjust your improvement factor or credit to account for uncertainty or other relevant factors.

(c) You may perform A to B testing by measuring emissions from the vehicles during chassis testing or from in-use on-road testing. You may also ask to use modified powertrain testing. If you use on-road testing, we recommend that you test according to SAE J1321, Fuel Consumption Test Procedure—Type II, revised February 2012, or SAE J1526, SAE Fuel Consumption Test Procedure (Engineering Method), Revised September 2015 (see § 1037.810 for information on availability of SAE standards), subject to the following provisions:

(1) The minimum route distance is 100 miles.

(2) The route selected must be representative in terms of grade. We will take into account published and relevant research in determining whether the grade is representative.

(3) Control vehicle speed over the route to be representative of the drive-cycle weighting adopted for each regulatory subcategory, as specified in § 1037.510(c), or apply a correction to account for the appropriate weighting. For example, if the route selected for an evaluation of a combination tractor with a sleeper cab contains only interstate driving at 65 mi/hr, the improvement factor would apply only to 86 percent of the weighted result.

(4) The ambient air temperature must be between (5 and 35) °C, unless the technology requires other temperatures for demonstration.

(5) We may allow you to use a Portable Emissions Measurement System (PEMS) device for measuring CO2 emissions during the on-road testing.

(d) Send your request to the Designated Compliance Officer. We recommend that you do not begin collecting test data (for submission to EPA) before contacting us. For technologies for which the engine manufacturer could also claim credits (such as transmissions in certain circumstances), we may require you to include a letter from the engine manufacturer stating that it will not seek credits for the same technology. Your request must contain the following items:

(1) A detailed description of the off-cycle technology and how it functions to reduce CO2 emissions under conditions not represented on the duty cycles required for certification.

(2) A list of the vehicle configurations that will be equipped with the technology.

(3) A detailed description and justification of the selected test vehicles.

(4) All testing and simulation data required under this section, plus any other data you have considered in your analysis. You may ask for our preliminary approval of your test plan under § 1037.210.

(5) A complete description of the methodology used to estimate the off-cycle benefit of the technology and all supporting data, including vehicle testing and in-use activity data. Also include a statement regarding your recommendation for applying the provisions of this section for the given technology as an improvement factor or a credit.

(6) An estimate of the off-cycle benefit by vehicle model, and the fleetwide benefit based on projected sales of vehicle models equipped with the technology.

(7) A demonstration of the in-use durability of the off-cycle technology, based on any available engineering analysis or durability testing data (either by testing components or whole vehicles).

(8) A recommended method for auditing production vehicles consistent with the intent of 40 CFR part 1068, subpart E. We may approve your recommended method or specify a different method.

(e) We may seek public comment on your request, consistent with the provisions of 40 CFR 86.1866. However, we will generally not seek public comment on credits or adjustments based on A to B chassis testing performed according to the duty-cycle testing requirements of this part or in-use testing performed according to paragraph (c) of this section.

(f) We may approve an improvement factor or credit for any configuration that is properly represented by your testing.

(1) For model years before 2021, you may continue to use an approved improvement factor or credit for any appropriate vehicle families in future model years through 2020.

(2) For model years 2021 and later, you may not rely on an approval for model years before 2021. You must separately request our approval before applying an improvement factor or credit under this section for Phase 2 and later vehicles, even if we approved an improvement factor or credit for similar vehicle models before model year 2021. Note that Phase 2 and later approval may carry over for multiple years.

(g) You normally may not calculate off-cycle credits or improvement factors under this section for technologies represented by GEM, but we may allow you to do so by averaging multiple GEM runs for special technologies for which a single GEM run cannot accurately reflect in-use performance. For example, if you use an idle-reduction technology that is effective 80 percent of the time, we may allow you to run GEM with the technology active and with it inactive, and then apply an 80% weighting factor to calculate the off-cycle credit or improvement factor. You may need to perform testing to establish proper weighting factors or otherwise quantify the benefits of the special technologies.

(a) This section describes how to calculate emission credits for advanced technologies. You may calculate Phase 1 advanced technology credits through model year 2020 for hybrid vehicles with regenerative braking, vehicles equipped with Rankine-cycle engines, battery electric vehicles, and fuel cell electric vehicles. You may calculate Phase 2 advanced technology credits through model year 2026 for plug-in hybrid electric vehicles, battery electric vehicles, and fuel cell electric vehicles. You may calculate Phase 3 advanced technology credits for model year 2027 for plug-in hybrid electric vehicles, battery electric vehicles, and fuel cell electric vehicles. You may not generate credits for Phase 1 engine technologies for which the engines generate CO2 credits under 40 CFR part 1036.

(b) Generate Phase 1 advanced-technology credits for vehicles other than battery electric vehicles as follows:

(1) Measure the effectiveness of the advanced system by chassis-testing a vehicle equipped with the advanced system and an equivalent conventional vehicle, or by testing the hybrid systems and the equivalent non-hybrid systems as described in § 1037.555. Test the vehicles as specified in subpart F of this part. For purposes of this paragraph (b), a conventional vehicle is considered to be equivalent if it has the same footprint (as defined in 40 CFR 86.1803), vehicle service class, aerodynamic drag, and other relevant factors not directly related to the hybrid powertrain. If you use § 1037.540 to quantify the benefits of a hybrid system for PTO operation, the conventional vehicle must have the same number of PTO circuits and have equivalent PTO power. If you do not produce an equivalent vehicle, you may create and test a prototype equivalent vehicle. The conventional vehicle is considered Vehicle A and the advanced vehicle is considered Vehicle B. We may specify an alternate cycle if your vehicle includes a power take-off.

(2) Calculate an improvement factor and g/ton-mile benefit using the following equations and parameters:

(i) Improvement Factor = [(Emission Rate A)−(Emission Rate B)]/(Emission Rate A).

(ii) g/ton-mile benefit = Improvement Factor × (GEM Result B).

(iii) Emission Rates A and B are the g/ton-mile CO2 emission rates of the conventional and advanced vehicles, respectively, as measured under the test procedures specified in this section. GEM Result B is the g/ton-mile CO2 emission rate resulting from emission modeling of the advanced vehicle as specified in § 1037.520.

(3) If you apply an improvement factor to multiple vehicle configurations using the same advanced technology, use the vehicle configuration with the smallest potential reduction in greenhouse gas emissions resulting from the hybrid capability.

(4) Use the equation in § 1037.705 to convert the g/ton-mile benefit to emission credits (in Mg). Use the g/ton-mile benefit in place of the (Std−FEL) term.

(c) See § 1037.540 for special testing provisions related to Phase 1 vehicles equipped with hybrid power take-off units.

(d) For Phase 2 and Phase 3 plug-in hybrid electric vehicles and for fuel cells powered by any fuel other than hydrogen, calculate CO2 credits using an FEL based on emission measurements from powertrain testing. Phase 2 and Phase 3 advanced technology credits do not apply for hybrid vehicles that have no plug-in capability.

(e) [Reserved]

(f) For battery electric vehicles and for fuel cell electric vehicles, calculate CO2 credits using an FEL of 0 g/ton-mile. Note that these vehicles are subject to compression-ignition standards for CO2.

(g) As specified in subpart H of this part, advanced-technology credits generated from Phase 1 vehicles under this section may be used under this part outside of the averaging set in which they were generated, or they may be used under 40 CFR part 86, subpart S, or 40 CFR part 1036. Advanced-technology credits generated from Phase 2 and later vehicles are subject to the averaging-set restrictions that apply to other emission credits.

(h) You may certify using both provisions of this section and the off-cycle technology provisions of § 1037.610, provided you do not double count emission benefits.

This section describes certain circumstances in which multiple manufacturers share responsibilities for vehicles they produce together. This section does not limit responsibilities that apply under the Act or these regulations for anyone meeting the definition of “manufacturer” in § 1037.801. Note that the definition of manufacturer is broad and can include persons not commercially considered to be manufacturers.

(a) The following provisions apply when there are multiple persons meeting the definition of manufacturer in § 1037.801:

(1) Each person meeting the definition of manufacturer must comply with the requirements of this part that apply to manufacturers. However, if one person complies with a specific requirement for a given vehicle, then all manufacturers are deemed to have complied with that specific requirement.

(2) We will apply the requirements of subparts C and D of this part to the manufacturer that obtains the certificate of conformity for the vehicle. Other manufacturers are required to comply with the requirements of subparts C and D of this part only when notified by us. In our notification, we will specify a reasonable time period in which you need to comply with the requirements identified in the notice. See § 1037.601 for the applicability of 40 CFR part 1068 to these other manufacturers and remanufacturers.

(b) The provisions of § 1037.621, including delegated assembly, apply for certifying manufacturers that rely on other manufacturers to finish assembly in a certified configuration. The provisions of § 1037.622 generally apply for manufacturers that ship vehicles subject to the requirements of this part to a certifying secondary vehicle manufacturer. The provisions of § 1037.622 also apply to the secondary vehicle manufacturer. If you hold the certificate of conformity for a vehicle only with respect to exhaust or evaporative emissions, and a different company holds the other certificate of conformity for that vehicle, the provisions of § 1037.621 apply with respect to the certified configuration as described in your application for certification, and the provisions of § 1037.622 apply with respect to the certified configuration as described in the other manufacturer's application for certification.

(c) Component manufacturers (such as tire manufacturers) providing test data to certifying vehicle manufacturers are responsible as follows for test components and emission test results provided to vehicle manufacturers for the purpose of certification under this part:

(1) Such test results are deemed under § 1037.825 to be submissions to EPA. This means that you may be subject to criminal penalties under 18 U.S.C. 1001 if you knowingly submit false test results to the certifying manufacturer.

(2) You may not cause a vehicle manufacturer to violate the regulations by rendering inaccurate emission test results you provide (or emission test results from testing of test components you provide) to the vehicle manufacturer (see 40 CFR 1068.101(c)).

(3) Your provision of test components and/or emission test results to vehicle manufacturers for the purpose of certifying under this part are deemed to be an agreement to provide components to EPA for confirmatory testing under § 1037.235.

(d) Component manufacturers may contractually agree to process emission warranty claims on behalf of the certifying manufacturer with respect to those components, as follows:

(1) Your fulfillment of the warranty requirements of this part is deemed to fulfill the vehicle manufacturer's warranty obligations under this part with respect to components covered by your warranty.

(2) You may not cause a vehicle manufacturer to violate the regulations by failing to fulfill the emission warranty requirements that you contractually agreed to fulfill (see 40 CFR 1068.101(c)).

(e) We may require component manufacturers to provide information or take other actions under 42 U.S.C. 7542. For example, we may require component manufacturers to test components they produce.

(a) This section describes provisions that allow certificate holders to sell or ship vehicles that are missing certain emission-related components if those components will be installed by a secondary vehicle manufacturer. Paragraph (g) of this section similarly describes how dealers and distributors may modify new vehicles with your advance approval. (Note: See § 1037.622 for provisions related to manufacturers introducing into U.S. commerce partially complete vehicles for which a secondary vehicle manufacturer holds the certificate of conformity.)

(b) You do not need an exemption to ship a vehicle that does not include installation or assembly of certain emission-related components if those components are shipped along with the vehicle. For example, you may generally ship fuel tanks and aerodynamic devices along with vehicles rather than installing them on the vehicle before shipment. We may require you to describe how you plan to use this provision.

(c) You may ask us at the time of certification for an exemption to allow you to ship your vehicles without emission-related components. If we allow this, you must provide emission-related installation instructions as specified in § 1037.130. You must follow delegated-assembly requirements in 40 CFR 1068.261 if you rely on secondary vehicle manufacturers to install certain technologies or components as specified in paragraph (d) of this section. For other technologies or components, we may specify conditions that we determine are needed to ensure that shipping the vehicle without such components will not result in the vehicle being operated outside of its certified configuration; this may include a requirement to comply with the delegated-assembly provisions in paragraph (d) of this section. We may consider your past performance when we specify the conditions that apply.

(d) Delegated-assembly provisions apply as specified in this paragraph (d) if the certifying vehicle manufacturer relies on a secondary vehicle manufacturer to procure and install auxiliary power units, aerodynamic devices, hybrid components (for powertrain or power take-off), or natural gas fuel tanks. These provisions do not apply for other systems or components, such as air conditioning lines and fittings, except as specified in paragraph (c) of this section. Apply the provisions of 40 CFR 1068.261, with the following exceptions and clarifications:

(1) Understand references to “engines” to refer to vehicles.

(2) Understand references to “aftertreatment components” to refer to any relevant emission-related components under this paragraph (d).

(3) Understand “equipment manufacturers” to be secondary vehicle manufacturers.

(4) The provisions of 40 CFR 1068.261(b), (c)(7), (d), and (e) do not apply. Accordingly, the provisions of 40 CFR 1068.261(c) apply regardless of pricing arrangements.

(e) Secondary vehicle manufacturers must follow the engine manufacturer's emission-related installation instructions. Not meeting the manufacturer's emission-related installation instructions is a violation of one or more of the prohibitions of § 1068.101. We may also require secondary vehicle manufacturers to recall defective vehicles under 40 CFR 1068.505 if we determine that their manufacturing practices caused vehicles to not conform to the regulations. Secondary vehicle manufacturers may be required to meet additional requirements if the certifying vehicle manufacturer delegates final assembly of emission controls as described in paragraph (d) of this section.

(f) Except as allowed by § 1037.622, the provisions of this section apply to manufacturers for glider kits they produce. Note that under § 1037.620, glider kit manufacturers are generally presumed to be responsible (in whole or in part) for compliance with respect to vehicles produced from their glider kits, even if a secondary vehicle manufacturer holds the certificate under § 1037.622.

(g) We may allow certifying vehicle manufacturers to authorize dealers or distributors to reconfigure/recalibrate vehicles after the vehicles have been introduced into commerce if they have not yet been delivered to the ultimate purchaser as follows:

(1) This allowance is limited to changes from one certified configuration to another, as noted in the following examples:

(i) If your vehicle family includes certified configurations with different axle ratios, you may authorize changing from one certified axle ratio to another.

(ii) You may authorize adding a certified APU to a tractor.

(2) Your final ABT report must accurately describe the vehicle's certified configuration as delivered to the ultimate purchaser. This means that the allowance no longer applies after you submit the final ABT report.

(3) The vehicle label must accurately reflect the final vehicle configuration.

(4) You must keep records to document modifications under this paragraph (g).

(5) Dealers and distributors must keep a record of your authorizing instructions. Dealers and distributors that fail to follow your instructions or otherwise make unauthorized changes may be committing a tampering violation as described in 40 CFR 1068.105(b).

This section specifies how manufacturers may introduce partially complete vehicles into U.S. commerce (or in the case of certain custom vehicles, introduce complete vehicles into U.S. commerce for modification by a small manufacturer). The provisions of this section are intended to accommodate normal business practices without compromising the effectiveness of certified emission controls. You may not use the provisions of this section to circumvent the intent of this part. For vehicles subject to both exhaust greenhouse gas and evaporative standards, the provisions of this part apply separately for each certificate.

(a) The provisions of this section allow manufacturers to ship partially complete vehicles to secondary vehicle manufacturers or otherwise introduce them into U.S. commerce in the following circumstances:

(1) Certified vehicles. Manufacturers may introduce partially complete tractors into U.S. commerce if they are covered by certificates of conformity and are in certified configurations. See § 1037.621 for vehicles not yet in a certified configuration when introduced into U.S. commerce.

(2) Uncertified vehicles that will be certified by secondary vehicle manufacturers. Manufacturers may introduce into U.S. commerce partially complete vehicles for which they do not hold the required certificate of conformity only as allowed by paragraph (b) of this section; however, the requirements of this section do not apply for tractors or vocational vehicles with a date of manufacture before January 1, 2022, that are produced by a secondary vehicle manufacturer if they are excluded from the standards of this part under § 1037.150(c).

(3) Exempted vehicles. Manufacturers may introduce into U.S. commerce partially complete vehicles without a certificate of conformity if the vehicles are exempt under this part or under 40 CFR part 1068. This may involve the secondary vehicle manufacturer qualifying for the exemption.

(4) Small manufacturers modifying certified tractors. Small manufacturers that build custom sleeper cabs or natural gas-fueled tractors may modify complete or incomplete vehicles certified as tractors, as specified by paragraph (d) of this section.

(b) The provisions of this paragraph (b) generally apply where the secondary vehicle manufacturer has substantial control over the design and assembly of emission controls. They also apply where a secondary vehicle manufacturer qualifies for a permanent exemption. In unusual circumstances we may allow other secondary vehicle manufacturers to use these provisions. In determining whether a manufacturer has substantial control over the design and assembly of emission controls, we would consider the degree to which the secondary vehicle manufacturer would be able to ensure that the engine and vehicle will conform to the regulations in their final configurations.

(1) A secondary vehicle manufacturer may finish assembly of partially complete vehicles in the following cases:

(i) It obtains a vehicle that is not fully assembled with the intent to manufacture a complete vehicle in a certified or exempted configuration. For example, this would apply where a glider vehicle assembler holds a certificate that allows the assembler to produce certified glider vehicles from glider kits.

(ii) It obtains a vehicle with the intent to modify it to a certified configuration before it reaches the ultimate purchaser. For example, this may apply for converting a gasoline-fueled vehicle to operate on natural gas under the terms of a valid certificate.

(2) Manufacturers may introduce partially complete vehicles into U.S. commerce as described in this paragraph (b) if they have a written request for such vehicles from a secondary vehicle manufacturer that will finish the vehicle assembly and has certified the vehicle (or the vehicle has been exempted or excluded from the requirements of this part). The written request must include a statement that the secondary vehicle manufacturer has a certificate of conformity (or exemption/exclusion) for the vehicle and identify a valid vehicle family name associated with each vehicle model ordered (or the basis for an exemption/exclusion). The original vehicle manufacturer must apply a removable label meeting the requirements of 40 CFR 1068.45(b) that identifies the corporate name of the original manufacturer and states that the vehicle is exempt under the provisions of § 1037.622. The name of the certifying manufacturer must also be on the label or, alternatively, on the bill of lading that accompanies the vehicles during shipment. The original manufacturer may not apply a permanent emission control information label identifying the vehicle's eventual status as a certified vehicle. Note that an exemption allowing a glider assembler to install an exempt engine does not necessarily exempt the vehicle from the requirements of this part.

(3) If you are the secondary vehicle manufacturer and you will hold the certificate, you must include the following information in your application for certification:

(i) Identify the original manufacturer of the partially complete vehicle or of the complete vehicle you will modify.

(ii) Describe briefly how and where final assembly will be completed. Specify how you have the ability to ensure that the vehicles will conform to the regulations in their final configuration. (Note: This section prohibits using the provisions of this paragraph (b) unless you have substantial control over the design and assembly of emission controls.)

(iii) State unconditionally that you will not distribute the vehicles without conforming to all applicable regulations.

(4) If you are a secondary vehicle manufacturer and you are already a certificate holder for other families, you may receive shipment of partially complete vehicles after you apply for a certificate of conformity but before the certificate's effective date. This exemption allows the original manufacturer to ship vehicles after you have applied for a certificate of conformity. Manufacturers may introduce partially complete vehicles into U.S. commerce as described in this paragraph (b)(4) if they have a written request for such vehicles from a secondary vehicle manufacturer stating that the application for certification has been submitted (instead of the information we specify in paragraph (b)(2) of this section). We may set additional conditions under this paragraph (b)(4) to prevent circumvention of regulatory requirements.

(5) The provisions of this section also apply for shipping partially complete vehicles if the vehicle is covered by a valid exemption and there is no valid family name that could be used to represent the vehicle model. Unless we approve otherwise in advance, you may do this only when shipping engines to secondary vehicle manufacturers that are certificate holders. In this case, the secondary vehicle manufacturer must identify the regulatory cite identifying the applicable exemption instead of a valid family name when ordering engines from the original vehicle manufacturer.

(6) Both original and secondary vehicle manufacturers must keep the records described in this section for at least five years, including the written request for exempted vehicles and the bill of lading for each shipment (if applicable). The written request is deemed to be a submission to EPA.

(7) These provisions are intended only to allow secondary vehicle manufacturers to obtain or transport vehicles in the specific circumstances identified in this section so any exemption under this section expires when the vehicle reaches the point of final assembly identified in paragraph (b)(3)(ii) of this section.

(8) For purposes of this section, an allowance to introduce partially complete vehicles into U.S. commerce includes a conditional allowance to sell, introduce, or deliver such vehicles into commerce in the United States or import them into the United States. It does not include a general allowance to offer such vehicles for sale because this exemption is intended to apply only for cases in which the certificate holder already has an arrangement to purchase the vehicles from the original manufacturer. This exemption does not allow the original manufacturer to subsequently offer the vehicles for sale to a different manufacturer who will hold the certificate unless that second manufacturer has also complied with the requirements of this part. The exemption does not apply for any individual vehicles that are not labeled as specified in this section or which are shipped to someone who is not a certificate holder.

(9) We may suspend, revoke, or void an exemption under this section, as follows:

(i) We may suspend or revoke your exemption if you fail to meet the requirements of this section. We may suspend or revoke an exemption related to a specific secondary vehicle manufacturer if that manufacturer sells vehicles that are in not in a certified configuration in violation of the regulations. We may disallow this exemption for future shipments to the affected secondary vehicle manufacturer or set additional conditions to ensure that vehicles will be assembled in the certified configuration.

(ii) We may void an exemption for all the affected vehicles if you intentionally submit false or incomplete information or fail to keep and provide to EPA the records required by this section.

(iii) The exemption is void for a vehicle that is shipped to a company that is not a certificate holder or for a vehicle that is shipped to a secondary vehicle manufacturer that is not in compliance with the requirements of this section.

(iv) The secondary vehicle manufacturer may be liable for penalties for causing a prohibited act where the exemption is voided due to actions on the part of the secondary vehicle manufacturer.

(c) Provide instructions along with partially complete vehicles including all information necessary to ensure that an engine will be installed in its certified configuration.

(d) Small manufacturers that build custom sleeper cabs or natural gas-fueled tractors may modify complete or incomplete vehicles certified as tractors, subject to the provisions of this paragraph (d). Such businesses are secondary vehicle manufacturers.

(1) Secondary vehicle manufacturers may not modify the vehicle body in front of the b-pillar or increase the effective frontal area of the certified configuration including consideration of the frontal area of the standard trailer. For high-roof custom sleeper tractors, this would generally mean that no part of the added sleeper compartment may extend beyond 102 inches wide or 162 inches high (measured from the ground), which are the dimensions of the standard trailer for high-roof tractors under this part. Note that these dimensions have a tolerance of ±2 inches.

(2) The certifying manufacturer may have responsibilities for the vehicle under this section, as follows:

(i) If the vehicle being modified is a complete tractor in a certified configuration, the certifying manufacturer has no additional responsibilities for the vehicle under this section.

(ii) If the vehicle being modified is partially complete only because it lacks body components to the rear of the b-pillar (but is otherwise a complete tractor in a certified configuration), the certifying manufacturer has no additional responsibilities for the vehicle under this section.

(iii) If the vehicle being modified is an incomplete tractor not in a certified configuration, the certifying manufacturer must comply with the provisions of § 1037.621 for the vehicle.

(3) The secondary vehicle manufacturer must add a permanent supplemental label to the vehicle near the original manufacturer's emission control information label. On the label identify your corporate name and include the statement: “THIS TRACTOR WAS MODIFIED UNDER 40 CFR 1037.622.”

(4) See § 1037.150 for additional interim options that may apply.

(5) The provisions of this paragraph (d) may apply separately for vehicle greenhouse gas, evaporative, and refueling emission standards.

(6) Modifications under this paragraph (d) do not violate 40 CFR 1068.101(b)(1).

(a) General provisions. This section allows a vehicle manufacturer to reclassify certain tractors as vocational tractors. Vocational tractors are treated as vocational vehicles and are exempt from the standards of § 1037.106. Note that references to “tractors” outside of this section mean non-vocational tractors.

(1) This allowance is intended only for vehicles that do not typically operate at highway speeds, or would otherwise not benefit from efficiency improvements designed for line-haul tractors. This allowance is limited to the following vehicle and application types:

(i) Low-roof tractors intended for intra-city pickup and delivery, such as those that deliver bottled beverages to retail stores.

(ii) Tractors intended for off-road operation (including mixed service operation that does not qualify for an exemption under § 1037.631), such as those with reinforced frames and increased ground clearance. This includes drayage tractors.

(iii) Model year 2020 and earlier tractors with a gross combination weight rating (GCWR) at or above 120,000 pounds. Note that Phase 2 and later tractors meeting the definition of heavy-haul tractor in § 1037.801 must be certified to the heavy-haul standards in § 1037.106 or § 1037.670.

(2) Where we determine that a manufacturer is not applying this allowance in good faith, we may require the manufacturer to obtain preliminary approval before using this allowance.

(b) Requirements. The following requirements apply with respect to tractors reclassified under this section:

(1) The vehicle must fully conform to all requirements applicable to vocational vehicles under this part.

(2) Vehicles reclassified under this section must be certified as a separate vehicle family. However, they remain part of the vocational regulatory subcategory and averaging set that applies for their service class.

(3) You must include the following additional statement on the vehicle's emission control information label under § 1037.135: “THIS VEHICLE WAS CERTIFIED AS A VOCATIONAL TRACTOR UNDER 40 CFR 1037.630.”

(4) You must keep records for three years to document your basis for believing the vehicles will be used as described in paragraph (a)(1) of this section. Include in your application for certification a brief description of your basis.

(c) Production limit. No manufacturer may produce more than 21,000 Phase 1 vehicles under this section in any consecutive three model year period. This means you may not exceed 6,000 in a given model year if the combined total for the previous two years was 15,000. The production limit applies with respect to all Class 7 and Class 8 Phase 1 tractors certified or exempted as vocational tractors. No production limit applies for tractors subject to Phase 2 and later standards.

(d) Off-road exemption. All the provisions of this section apply for vocational tractors exempted under § 1037.631, except as follows:

(1) The vehicles are required to comply with the requirements of § 1037.631 instead of the requirements that would otherwise apply to vocational vehicles. Vehicles complying with the requirements of § 1037.631 and using an engine certified to the standards of 40 CFR part 1036 are deemed to fully conform to all requirements applicable to vocational vehicles under this part.

(2) The vehicles must be labeled as specified under § 1037.631 instead of as specified in paragraph (b)(3) of this section.

This section provides an exemption from the greenhouse gas standards of this part for certain vocational vehicles (including certain vocational tractors) that are intended to be used extensively in off-road environments such as forests, oil fields, and construction sites. This section does not exempt engines used in vocational vehicles from the standards of 40 CFR part 86 or part 1036. Note that you may not include these exempted vehicles in any credit calculations under this part.

(a) Qualifying criteria. 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 (a)(1) of this section and at least one of the criteria of paragraph (a)(2) of this section. See § 1037.105(h) for alternate Phase 2 and Phase 3 standards that apply for vehicles meeting only one of these sets of criteria.

(1) 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.

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

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

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

(iii) 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.

(iv) Have a maximum speed at or below 54 mi/hr. You 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. You may alternatively limit vehicle speed by programming the engine or vehicle's electronic control module in a way that is tamper-proof.

(b) Tractors. The provisions of this section may apply for tractors only if each tractor qualifies as a vocational tractor under § 1037.630.

(c) Recordkeeping and reporting. (1) You must keep records to document that your 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. We may review these records at any time.

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

(3) Within 90 days after the end of each model year, you must send to the Designated Compliance Officer a report with the following information:

(i) A description of each exempted vehicle configuration, including an explanation of why it qualifies for this exemption.

(ii) The number of vehicles exempted for each vehicle configuration.

(d) Labeling. You must include the following additional statement on the vehicle's emission control information label under § 1037.135: “THIS VEHICLE WAS EXEMPTED UNDER 40 CFR 1037.631.”

Except as specified in § 1037.150, the requirements of this section apply beginning January 1, 2017.

(a) Vehicles produced from glider kits and other glider vehicles are subject to the same standards as other new vehicles, including the applicable vehicle standards described in Subpart B of this part. Note that this requirement for the vehicle generally applies even if the engine meets the criteria of paragraph (c)(1) of this section. For engines originally produced before 2017, if you are unable to obtain a fuel map for an engine you may ask to use a default map, consistent with good engineering judgment.

(b) Section 1037.601(a)(1) disallows the introduction into U.S. commerce of a new tractor or vocational vehicle (including a vehicle assembled from a glider kit) unless it has an engine that is certified to the applicable standards in 40 CFR parts 86 and 1036. Except as specified otherwise in this part, the standards apply for engines used in glider vehicles as follows:

(1) The engine must meet the greenhouse gas standards of 40 CFR part 1036 that apply for the engine model year corresponding to the vehicle's date of manufacture. For example, for a vehicle with a 2024 date of manufacture, the engine must meet the greenhouse gas standards that apply for model year 2024.

(2) The engine must meet the criteria pollutant standards of 40 CFR part 86 or 40 CFR part 1036 that apply for the engine model year corresponding to the vehicle's date of manufacture.

(3) The engine may be from an earlier model year if the standards were identical to the currently applicable engine standards.

(4) Note that alternate standards or requirements may apply under § 1037.150.

(c) The engine standards identified in paragraph (b) of this section do not apply for certain engines when used in glider kits. These engines remain subject to the standards to which they were previously certified.

(1) The allowance in this paragraph (c) applies only for the following engines:

(i) Certified engines still within their original useful life in terms of both miles and years. Glider vehicles produced using engines meeting this criterion are exempt from the requirements of paragraph (a) of this section if the glider vehicle configuration is identical to a configuration previously certified to the requirements of this part 1037 for a model year the same as or later than the model year of the engine.

(ii) Certified engines of any age with less than 100,000 miles of engine operation. This is intended for specialty vehicles (such as fire trucks) that have very low usage rates. These vehicles are exempt from the requirements of paragraph (a) of this section, provided the completed vehicle is returned to the owner of the engine in a configuration equivalent to that of the donor vehicle.

(iii) Certified engines less than three years old with any number of accumulated miles of engine operation. Vehicles using these engines must comply with the requirements of paragraph (a) of this section.

(2) For remanufactured engines, these eligibility criteria apply based on the original date of manufacture rather than the date of remanufacture. For example, an engine originally manufactured in 2003 that is remanufactured in 2012 after 350,000 miles, then accumulates an additional 150,000 miles before being installed in a model year 2020 glider would be considered to be 17 years old and to have accumulated 500,000 miles.

(3) The provisions of this paragraph (c) apply only where you can show that one or more criteria have been met. For example, to apply the criterion of paragraph (c)(1)(i) or (ii), you must be able prove the number of miles the engine has accumulated.

(d) All engines used in glider vehicles (including remanufactured engines) must be in a certified configuration and properly labeled. This requirement applies equally to any engine covered by this section. Depending on the model year of the engine (and other applicable provisions of this section), it may be permissible for the engine to remain in its original certified configuration or another configuration of the same original model year. However, it may be necessary to modify the engine to a newer certified configuration.

(e) The following additional provisions apply:

(1) The Clean Air Act definition of “manufacturer” includes anyone who assembles motor vehicles, including entities that install engines in or otherwise complete assembly of glider kits.

(2) Vehicle manufacturers (including assemblers) producing glider vehicles must comply with the reporting and recordkeeping requirements in § 1037.250.

(3) Manufacturers of glider kits providing glider kits for the purpose of allowing another manufacturer to assemble vehicles under this section are subject to the provisions of §§ 1037.620 through 1037.622, as applicable. For example, introducing an uncertified glider kit into U.S. commerce may subject you to penalties under 40 CFR 1068.101 if the completed glider vehicle does not conform fully with the regulations of the part at any point before being placed into service.

This section specifies provisions that apply for vehicle speed limiters (VSLs) that you model under § 1037.520. This section is written to apply for tractors; however, you may use good engineering judgment to apply equivalent adjustments for Phase 2 and later vocational vehicles with vehicle speed limiters.

(a) General. The regulations of this part do not constrain how you may design VSLs for your vehicles. For example, you may design your VSL to have a single fixed speed limit or a soft-top speed limit. You may also design your VSL to expire after accumulation of a predetermined number of miles. However, designs with soft tops or expiration features are subject to proration provisions under this section that do not apply to fixed VSLs that do not expire.

(b) Definitions. The following definitions apply for purposes of this section:

(1) Default speed limit means the speed limit that normally applies for the vehicle, except as follows:

(i) The default speed limit for adjustable VSLs must represent the speed limit that applies when the VSL is adjusted to its highest setting under paragraph (c) of this section.

(ii) For VSLs with soft tops, the default speed does not include speeds possible only during soft-top operation.

(iii) For expiring VSLs, the default does not include speeds that are possible only after expiration.

(2) Soft-top speed limit means the highest speed limit that applies during soft-top operation.

(3) Maximum soft-top duration means the maximum amount of time that a vehicle could operate above the default speed limit.

(4) Certified VSL means a VSL configuration that applies when a vehicle is new and until it expires.

(5) Expiration point means the mileage at which a vehicle's certified VSL expires (or the point at which tamper protections expire).

(6) Effective speed limit has the meaning given in paragraph (d) of this section.

(c) Adjustments. You may design your VSL to be adjustable; however, this may affect the value you use in GEM.

(1) Except as specified in paragraph (c)(2) of this section, any adjustments that can be made to the engine, vehicle, or their controls that change the VSL's actual speed limit are considered to be adjustable operating parameters. Compliance is based on the vehicle being adjusted to the highest speed limit within this range.

(2) The following adjustments are not adjustable parameters:

(i) Adjustments made only to account for changing tire size or final drive ratio.

(ii) Adjustments protected by encrypted controls or passwords.

(iii) Adjustments possible only after the VSL's expiration point.

(d) Effective speed limit. (1) For VSLs without soft tops or expiration points that expire before 1,259,000 miles, the effective speed limit is the highest speed limit that results by adjusting the VSL or other vehicle parameters consistent with the provisions of paragraph (c) of this section.

(2) For VSLs with soft tops and/or expiration points, the effective speed limit is calculated as specified in this paragraph (d)(2), which is based on 10 hours of operation per day (394 miles per day for day cabs and 551 miles per day for sleeper cabs). Note that this calculation assumes that a fraction of this operation is speed-limited (3.9 hours and 252 miles for day cabs, and 7.3 hours and 474 miles for sleeper cabs). Use the following equation to calculate the effective speed limit, rounded to the nearest 0.1 mi/hr:

Section 1037.225 describes how to change the FEL for a vehicle family during the model year. This section, which describes how you may ask us to increase a vehicle family's FEL after the end of the model year, is intended to address circumstances in which it is in the public interest to apply a higher in-use FEL based on forfeiting an appropriate number of emission credits. For example, this may be appropriate where we determine that recalling vehicles would not significantly reduce in-use emissions. We will generally not allow this option where we determine the credits being forfeited would likely have expired.

(a) You may ask us to increase a vehicle family's FEL after the end of the model year if you believe some of your in-use vehicles exceed the CO2 FEL that applied during the model year (or the CO2 emission standard if the family did not generate or use emission credits). We may consider any available information in making our decision to approve or deny your request.

(b) If we approve your request under this section, you must apply emission credits to cover the increased FEL for all affected vehicles. Apply the emission credits as part of your credit demonstration for the current production year. Include the appropriate calculations in your final report under § 1037.730.

(c) Submit your request to the Designated Compliance Officer. Include the following in your request:

(1) Identify the names of each vehicle family that is the subject of your request. Include separate family names for different model years

(2) Describe why your request does not apply for similar vehicle models or additional model years, as applicable.

(3) Identify the FEL that applied during the model year for each configuration and recommend replacement FELs for in-use vehicles; include a supporting rationale to describe how you determined the recommended replacement FELs.

(4) Describe whether the needed emission credits will come from averaging, banking, or trading.

(d) If we approve your request, we will identify one or more replacement FELs, as follows:

(1) Where your vehicle family includes more than one sub-family with different FELs, we may apply a higher FEL within the family than was applied to the vehicle's configuration in your final ABT report. For example, if your vehicle family included three sub-families, with FELs of 200 g/ton-mile, 210 g/ton-mile, and 220 g/ton-mile, we may apply a 220 g/ton-mile in-use FEL to vehicles that were originally designated as part of the 200 g/ton-mile or 210 g/ton-mile sub-families.

(2) Without regard to the number of sub-families in your certified vehicle family, we may specify one or more new sub-families with higher FELs than you included in your final ABT report. We may apply these higher FELs as in-use FELs for your vehicles. For example, if your vehicle family included three sub-families, with FELs of 200 g/ton-mile, 210 g/ton-mile, and 220 g/ton-mile, we may specify a new 230 g/ton-mile sub-family.

(3) Our selected values for the replacement FEL will reflect our best judgment to accurately reflect the actual in-use performance of your vehicles, consistent with the testing provisions specified in this part.

(4) We may apply the higher FELs to other vehicle families from the same or different model years to the extent they used equivalent emission controls. We may include any appropriate conditions with our approval.

(e) If we order a recall for a vehicle family under 40 CFR 1068.505, we will no longer approve a replacement FEL under this section for any of your vehicles from that vehicle family, or from any other vehicle family that relies on equivalent emission controls.

(a) General. Vehicle modifications during and after the useful life are presumed to violate 42 U.S.C. 7522(a)(3)(A) if they involve removing or rendering inoperative any emission control device installed to comply with the requirements of this part 1037. This section specifies vehicle modifications that may occur in certain circumstances after a vehicle reaches the end of its regulatory useful life. EPA may require a higher burden of proof with respect to modifications that occur within the useful life period, and the specific examples presented here do not necessarily apply within the useful life. This section also does not apply with respect to engine modifications or recalibrations.

(b) Allowable modifications. You may modify a vehicle for the purpose of reducing emissions, provided you have a reasonable technical basis for knowing that such modification will not increase emissions of any other pollutant. “Reasonable technical basis” has the meaning given in 40 CFR 1068.30. This generally requires you to have information that would lead an engineer or other person familiar with engine and vehicle design and function to reasonably believe that the modifications will not increase emissions of any regulated pollutant.

(c) Examples of allowable modifications. The following are examples of allowable modifications:

(1) It is generally allowable to remove tractor roof fairings after the end of the vehicle's useful life if the vehicle will no longer be used primarily to pull box vans.

(2) Other fairings may be removed after the end of the vehicle's useful life if the vehicle will no longer be used significantly on highways with a vehicle speed of 55 miles per hour or higher.

(d) Examples of prohibited modifications. The following are examples of modifications that are not allowable:

(1) No person may disable a vehicle speed limiter prior to its expiration point.

(2) No person may remove aerodynamic fairings from tractors that are used primarily to pull box vans on highways.

This section specifies requirements that apply for idle-reduction technologies modeled under § 1037.520. It does not apply for idle-reduction technologies you do not model under § 1037.520.

(a) Minimum requirements. Idle-reduction technologies must meet all the following requirements to be modeled under § 1037.520 except as specified in paragraphs (b) and (c) of this section:

(1) Automatic engine shutdown (AES) systems. The system must shut down the engine within a threshold inactivity period of 60 seconds or less for vocational vehicles and 300 seconds or less for tractors when all the following conditions are met:

(i) The transmission is set to park, or the transmission is in neutral with the parking brake engaged. This is “parked idle.”

(ii) The operator has not reset the system timer within the specified threshold inactivity period by changing the position of the accelerator, brake, or clutch pedal; or by resetting the system timer with some other mechanism we approve.

(iii) You may identify systems as “tamper-resistant” if you make no provision for vehicle owners, dealers, or other service outlets to adjust the threshold inactivity period.

(iv) For Phase 2 and later tractors, you may identify AES systems as “adjustable” if, before delivering to the ultimate purchaser, you enable authorized dealers to modify the vehicle in a way that disables the AES system or makes the threshold inactivity period longer than 300 seconds. However, the vehicle may not be delivered to the ultimate purchaser with the AES system disabled or the threshold inactivity period set longer than 300 seconds. You may allow dealers or repair facilities to make such modifications; this might involve password protection for electronic controls, or special tools that only you provide. Any dealers making any modifications before delivery to the ultimate purchaser must notify you, and you must account for such modifications in your production and ABT reports after the end of the model year. Dealers failing to provide prompt notification are in violation of the tampering prohibition of 40 CFR 1068.101(b)(1). Dealer notifications are deemed to be submissions to EPA. Note that these adjustments may not be made if the AES system was not “adjustable” when first delivered to the ultimate purchaser.

(v) For vocational vehicles, you may use the provisions of § 1037.610 to apply for an appropriate partial emission reduction for AES systems you identify as “adjustable.”

(2) Neutral idle. Phase 2 and later vehicles with hydrokinetic torque converters paired with automatic transmissions qualify for neutral-idle credit in GEM modeling if the transmission reduces torque equivalent to shifting into neutral throughout the interval during which the vehicle's brake pedal is depressed and the vehicle is at a zero-speed condition (beginning within five seconds of the vehicle reaching zero speed with the brake depressed). If a vehicle reduces torque partially but not enough to be equivalent to shifting to neutral, you may use the provisions of § 1037.610(g) to apply for an appropriate partial emission reduction; this may involve A to B testing with the powertrain test procedure in 40 CFR 1036.545 or the spin-loss portion of the transmission efficiency test in § 1037.565.

(3) Stop-start. Phase 2 and later vocational vehicles qualify for stop-start reduction in GEM modeling if the engine shuts down no more than 5 seconds after the vehicle's brake pedal is depressed when the vehicle is at a zero-speed condition.

(b) Override conditions. The system may limit activation of the idle-reduction technology while any of the conditions of this paragraph (b) apply. These conditions allow the system to delay engine shutdown, adjust engine restarting, or delay disengaging transmissions, but do not allow for resetting timers. Engines may restart and transmissions may re-engage during override conditions if the vehicle is set up to do this automatically. We may approve additional override criteria as needed to protect the engine and vehicle from damage and to ensure safe vehicle operation.

(1) For AES systems on tractors, the system may delay shutdown—

(i) When an exhaust emission control device is regenerating. The period considered to be regeneration for purposes of this allowance must be consistent with good engineering judgment and may differ in length from the period considered to be regeneration for other purposes. For example, in some cases it may be appropriate to include a cool down period for this purpose but not for infrequent regeneration adjustment factors.

(ii) When the vehicle's main battery state-of-charge is not sufficient to allow the main engine to be restarted.

(iii) When the vehicle's transmission, fuel, oil, or engine coolant temperature is too low or too high according to the manufacturer's specifications for protecting against system damage. This allows the engine to continue operating until it is in a predefined temperature range, within which the shutdown sequence of paragraph (a) of this section would resume.

(iv) When the vehicle's main engine is operating in power take-off (PTO) mode. For purposes of this paragraph (b), an engine is considered to be in PTO mode when a switch or setting designating PTO mode is enabled.

(v) When external ambient conditions prevent managing cabin temperatures for the driver's safety.

(vi) When necessary while servicing the vehicle, provided the deactivation of the AES system is accomplished using a diagnostic scan tool. The system must be automatically reactivated when the engine is shut down for more than 60 minutes.

(2) For AES systems on vocational vehicles, the system may limit activation—

(i) When any condition specified in paragraphs (b)(1)(i) through (v) of this section applies.

(ii) When the engine compartment is open.

(3) For neutral idle, the system may delay shifting the transmission to neutral—

(i) When the system meets the PTO conditions specified in paragraph (b)(1)(iv) of this section.

(ii) When the transmission is in reverse gear.

(iii) When the vehicle is ascending or descending a road with grade at or above 6.0%.

(4) For stop-start, the system may limit activation—

(i) When any condition specified in paragraph (b)(2) or (b)(3)(ii) or (iii) of this section applies.

(ii) When air brake pressure is too low according to the manufacturer's specifications for maintaining vehicle-braking capability.

(iii) When an automatic transmission is in “park” or “neutral” and the parking brake is engaged.

(iv) When recent vehicle speeds indicate an abnormally high shutdown and restart frequency, such as with congested driving. For example, a vehicle not exceeding 10 mi/hr for the previous 300 seconds or since the most recent engine start would be a proper basis for overriding engine shutdown. You may also design this override to protect against system damage or malfunction of safety systems.

(v) When the vehicle detects that a system or component is worn or malfunctioning in a way that could reasonably prevent the engine from restarting, such as low battery voltage.

(vi) When the steering angle is at or near the limit of travel.

(vii) When flow of diesel exhaust fluid is limited due to freezing.

(viii) When a sensor failure could prevent the anti-lock braking system from properly detecting vehicle speed.

(ix) When a protection mode designed to prevent component failure is active.

(x) When a fault on a system component needed for starting the engine is active.

(c) Adjustments to AES systems for Phase 1. (1) The AES system may include an expiration point (in miles) after which the AES system may be disabled. If your vehicle is equipped with an AES system that expires before 1,259,000 miles, adjust the model input as follows, rounded to the nearest 0.1 g/ton-mile: AES Input = 5 g CO2/ton-mile × (miles at expiration/1,259,000 miles).

(2) For AES systems designed to limit idling to a specific number of hours less than 1,800 hours over any 12-month period, calculate an adjusted AES input using the following equation, rounded to the nearest 0.1 g/ton-mile: AES Input = 5 g CO2/ton-mile × (1—(maximum allowable number of idling hours per year/1,800 hours)). This is an annual allowance that starts when the vehicle is new and resets every 12 months after that. Manufacturers may propose an alternate method based on operating hours or miles instead of years.

(d) Adjustable parameters. Provisions that apply generally with respect to adjustable parameters also apply to the AES system operating parameters, except the following are not considered to be adjustable parameters:

(1) Accelerator, brake, and clutch pedals, with respect to resetting the idle timer. Parameters associated with other timer reset mechanisms we approve are also not adjustable parameters.

(2) Bypass parameters allowed for vehicle service under paragraph (b)(1)(ii) of this section.

(3) Parameters that are adjustable only after the expiration point.

(e) PM limit for diesel APU. For model year 2020 and earlier tractors with a date of manufacture on or after January 1, 2018, the GEM credit for AES systems with OEM-installed diesel APUs is valid only if the engine is certified under 40 CFR part 1039 with a deteriorated emission level for particulate matter at or below 0.15 g/kW-hr, or if the engine or APU is certified to the standards specified in § 1037.106(g).

We may require manufacturers with annual U.S.-directed production volumes of greater than 20,000 tractors to perform testing as described in this section. Tractors may be new or used.

(a) Test model year 2021 and later tractors as follows:

(1) Each calendar year, we may require you to select for testing three sleeper cabs and two day cabs certified to Phase 1 or Phase 2 standards. If we do not identify certain vehicle configurations for your testing, select models that you project to be among your 12 highest-selling vehicle configurations for the given year.

(2) Set up the tractors on a chassis dynamometer and operate them over all applicable duty cycles from § 1037.510(a)(3). You may use emission-measurement systems meeting the specifications of 40 CFR part 1065, subpart J. Calculate coefficients for the road-load force equation as described in Section 10 of SAE J1263 or Section 11 of SAE J2263 (both incorporated by reference, see § 1037.810). Use standard payload. Measure emissions of NOX, PM, CO, NMHC, CO2, CH4, and N2O. Determine emission levels in g/ton-mile.

(b) Send us an annual report with your test results for each duty cycle and the corresponding GEM results. Send the report by the next October 1 after the year we select the vehicles for testing, or a later date that we approve. We may make your test data publicly available.

(c) We may approve your request to perform alternative testing that will provide equivalent or better information compared to the specified testing. For example, we may allow you to provide CO2 data from in-use operation or from manufacturer-run on-road testing as long as it allows for reasonable year-to-year comparisons and includes testing from production vehicles. We may also direct you to do less testing than we specify in this section.

(d) Greenhouse gas standards do not apply with respect to testing under this section. Note however that NTE standards apply for any qualifying operation that occurs during the testing in the same way that it would during any other in-use testing.

(a) You may certify model year 2026 and earlier tractors at or above 120,000 pounds GCWR to the following CO2 standards instead of the Phase 2 CO2 standards of § 1037.106:

(b) Determine subcategories as described in § 1037.230 for tractors that are not heavy-haul tractors. For example, the subcategory for tractors that would otherwise be considered Class 8 low-roof day cabs would be Heavy Class 8 Low-Roof Day Cabs and would be identified as HC8__DC__LR for the GEM run.

(c) Except for the CO2 standards of § 1037.106, all provisions applicable to tractors under this part continue to apply to tractors certified to the standards of this section. Include the following compliance statement on your label instead of the statement specified in § 1037.135(c)(8): “THIS VEHICLE COMPLIES WITH U.S. EPA REGULATIONS FOR [MODEL YEAR] HEAVY-DUTY VEHICLES UNDER 40 CFR 1037.670.”

(d) The optional emission standards in this section are intended primarily for tractors that will be exported; however, you may include any tractors certified under this section in your emission credit calculation under § 1037.705 if they are part of your U.S.-directed production volume.