§535.6. Measurement and calculation procedures. — Inbound Citations

(b) Manufacturers are required to conduct testing to demonstrate compliance with CO2 exhaust emissions standards in accordance with EPA's provisions in 40 CFR part 600, subpart B, 40 CFR 1036, subpart F, 40 CFR part 1037, subpart R, and 40 CFR part 1066. Manufacturers determine equivalent fuel consumption performance values for CO2 results as specified in § 535.6 and demonstrate compliance by comparing equivalent results to the applicable fuel consumption standards in § 535.5.

The terms manufacture, manufacturer, commercial medium-duty on highway vehicle, commercial heavy-duty on highway vehicle, fuel, and work truck are used as defined in 49 U.S.C. 32901. See 49 CFR 523.2 for general definitions related to NHTSA's fuel efficiency programs.

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

(1) Heavy-duty vocational vehicle subfamilies produced for Phase 1 must comply with the fuel consumption standards in paragraph (b)(3) of this section. For Phase 2, each vehicle manufacturer of heavy-duty vocational vehicle subfamilies must comply with the fuel consumption standards in paragraph (b)(4) of this section.

(i) For model years 2016 to 2020, the heavy-duty vocational vehicle category is subdivided by GVWR into three regulatory subcategories as defined in § 535.4, each with its own assigned standard.

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

(iii) For purposes of certifying vehicles to fuel consumption standards, manufacturers must divide their product lines in each regulatory subcategory into vehicle families that have similar emissions and fuel consumption features, as specified by EPA in 40 CFR 1037.230. These families will be subject to the applicable standards. Each vehicle family is limited to a single model year.

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

(B) [Reserved]

(i) For model years 2013 through 2015, a manufacturer may choose voluntarily to comply early with the fuel consumption standards provided in paragraph (b)(3) of this section. For example, a manufacturer may choose to comply early in order to begin accumulating credits through over-compliance with the applicable standards. A manufacturer choosing early compliance must comply with all the vehicles and engines it manufacturers in each regulatory category for a given model year.

(ii) A manufacturer must declare its intent to voluntarily comply with fuel consumption standards and identify its plans to comply before it submits its first application for a certificate of conformity for the respective model year as specified in § 535.8; and, once selected, the decision cannot be reversed and the manufacturer must continue to comply for each subsequent model year for all the vehicles and engines it manufacturers in each regulatory category for a given model year.

(3) The mandatory and voluntary fuel consumption standards for heavy-duty vocational vehicles are given in the following table:

(4) The mandatory fuel consumption standards for heavy-duty vocational vehicles are given in the following table:

(5) Manufacturers may specify a family emission limit (FEL) in terms of fuel consumption for each vehicle subfamily. The FEL may not be less than the result of fuel consumption modeling from 40 CFR 1037.520. The FELs is the fuel consumption standards for the vehicle subfamily instead of the standards specified in paragraph (b)(3) and (4) of this section and can be used for calculating fuel consumption credits in accordance with § 535.7.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

(10) The following useful life values apply for the standards of this section:

(i) 110,000 miles or 10 years, whichever comes first, for vocational LHD vehicles certified to Phase 1 standards.

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

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

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

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

(11) Recreational vehicles manufactured after model year 2020 must comply with the fuel consumption standards of this section. Manufacturers producing these vehicles may also certify to fuel consumption standards from 2014 through model year 2020. Manufacturers may earn credits retroactively for early compliance with fuel consumption standards. Once selected, a manufacturer cannot reverse the decision and the manufacturer must continue to comply for each subsequent model year for all the vehicles it manufacturers in each regulatory subcategory for a given model year.

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

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

(vi) Manufacturers may certify a vehicle or engine family using an FEL (as described in § 535.6) below the fuel consumption standard (as described in § 535.5) and choose not to generate conventional fuel consumption credits for that family. Manufacturers do not need to calculate fuel consumption credits for those families and do not need to submit or keep the associated records described in § 535.8 for these families. Manufacturers participating in NHTSA's FCC program must provide reports as specified in § 535.8.

(5) For Phase 2 vehicles, the GEM inputs described in paragraphs (b)(4)(i) through (v) of this section continue to apply. Note that the provisions related to vehicle speed limiters and automatic engine shutdown systems are available for vocational vehicles in Phase 2. The additional GEM inputs that apply for vocational vehicles and other tractor regulatory subcategories for demonstrating compliance with Phase 2 standards are as follows:

(i) Enter information from the engine manufacturer to describe the installed engine and its operating parameters as described in 40 CFR 1036.503 and 1037.520(f).

(ii) Enter information in accordance with 40 CFR 1037.520(g) for the vehicle and its operating parameters including:

(A) Transmission make, model and type;

(B) Drive axle configuration;

(C) Drive axle ratio, ka;

(D) GEM inputs associated with powertrain testing include powertrain family, transmission calibration identifier, test data from 40 CFR 1037.550, and the powertrain test configuration (dynamometer connected to transmission output or wheel hub).

(iii) Identify whether the manufacturer's vehicle has qualifying idle-reduction technologies, subject to the qualifying criteria in 40 and 1037.660 and enter values for stop start and neutral idle technologies as specified in 40 CFR 1037.520(h).

(iv) Manufacturers may use axle efficiency maps as described in 40 CFR 1037.560 and transmission efficiency maps as described in 40 CFR 1037.565 to replace the default values in GEM.

(v) Enter input values in GEM as follows to characterize the percentage CO2 emission reduction corresponding to certain technologies and vehicle configurations, or enter 0 as specified in 40 CFR 1037.520(j):

(A) Intelligent controls

(B) Accessory load

(C) Tire-pressure systems

(D) Extended-idle reduction

(E) Additional GEM inputs may apply as follows:

(1) Enter 1.7 and 0.9, respectively, for school buses and coach buses that have at least seven available forward gears.

(2) If the agencies approve an off-cycle technology under § 535.7(f) and 40 CFR 1037.610 in the form of an improvement factor, enter the improvement factor expressed as a percentage reduction in CO2 emissions. (Note: In the case of approved off-cycle technologies whose benefit is quantified as a g/ton-mile credit, apply the credit to the GEM result, not as a GEM input value.)

(3) Manufacturers may use values to characterize torque converters as inputs to GEM as specified in the procedure defined in 40 CFR 1037.570.

(4) Vocational vehicle manufacturers may optionally use values for neutral coasting in GEM as specified in 40 CFR 1037.520.

(vi) For vocational vehicles, determine the delta PTO emission result of the manufacturer's engine and hybrid power take-off system as described in 40 CFR 1037.540.

(vii) For vocational vehicles certified using the Regional duty cycle, enter ΔCdA values to account for using rear fairings and a reduced minimum frontal area as specified in 40 CFR 1037.520(m) and 1037.527.

(viii) For fuels other than those identified in GEM, perform the simulation by identifying the vehicle as being diesel-fueled if the engine is subject to the compression-ignition standard, or as being gasoline-fueled if the engine is subject to the spark-ignition standards. Correct the engine or powertrain fuel map for mass-specific net energy content as described in 40 CFR 1036.535(b).

(ix) A simplified versions of GEM applies for custom chassis vehicle subject § 535.5(b)(6) in accordance with 40 CFR 1037.520(a)(2)(ii).

(5) For Phase 2 vehicles, the GEM inputs described in paragraphs (b)(4)(i) through (v) of this section continue to apply. Note that the provisions related to vehicle speed limiters and automatic engine shutdown systems are available for vocational vehicles in Phase 2. The additional GEM inputs that apply for vocational vehicles and other tractor regulatory subcategories for demonstrating compliance with Phase 2 standards are as follows:

(i) Enter information from the engine manufacturer to describe the installed engine and its operating parameters as described in 40 CFR 1036.503 and 1037.520(f).

(ii) Enter information in accordance with 40 CFR 1037.520(g) for the vehicle and its operating parameters including:

(A) Transmission make, model and type;

(B) Drive axle configuration;

(C) Drive axle ratio, ka;

(D) GEM inputs associated with powertrain testing include powertrain family, transmission calibration identifier, test data from 40 CFR 1037.550, and the powertrain test configuration (dynamometer connected to transmission output or wheel hub).

(iii) Identify whether the manufacturer's vehicle has qualifying idle-reduction technologies, subject to the qualifying criteria in 40 and 1037.660 and enter values for stop start and neutral idle technologies as specified in 40 CFR 1037.520(h).

(iv) Manufacturers may use axle efficiency maps as described in 40 CFR 1037.560 and transmission efficiency maps as described in 40 CFR 1037.565 to replace the default values in GEM.

(v) Enter input values in GEM as follows to characterize the percentage CO2 emission reduction corresponding to certain technologies and vehicle configurations, or enter 0 as specified in 40 CFR 1037.520(j):

(A) Intelligent controls

(B) Accessory load

(C) Tire-pressure systems

(D) Extended-idle reduction

(E) Additional GEM inputs may apply as follows:

(1) Enter 1.7 and 0.9, respectively, for school buses and coach buses that have at least seven available forward gears.

(2) If the agencies approve an off-cycle technology under § 535.7(f) and 40 CFR 1037.610 in the form of an improvement factor, enter the improvement factor expressed as a percentage reduction in CO2 emissions. (Note: In the case of approved off-cycle technologies whose benefit is quantified as a g/ton-mile credit, apply the credit to the GEM result, not as a GEM input value.)

(3) Manufacturers may use values to characterize torque converters as inputs to GEM as specified in the procedure defined in 40 CFR 1037.570.

(4) Vocational vehicle manufacturers may optionally use values for neutral coasting in GEM as specified in 40 CFR 1037.520.

(vi) For vocational vehicles, determine the delta PTO emission result of the manufacturer's engine and hybrid power take-off system as described in 40 CFR 1037.540.

(vii) For vocational vehicles certified using the Regional duty cycle, enter ΔCdA values to account for using rear fairings and a reduced minimum frontal area as specified in 40 CFR 1037.520(m) and 1037.527.

(viii) For fuels other than those identified in GEM, perform the simulation by identifying the vehicle as being diesel-fueled if the engine is subject to the compression-ignition standard, or as being gasoline-fueled if the engine is subject to the spark-ignition standards. Correct the engine or powertrain fuel map for mass-specific net energy content as described in 40 CFR 1036.535(b).

(ix) A simplified versions of GEM applies for custom chassis vehicle subject § 535.5(b)(6) in accordance with 40 CFR 1037.520(a)(2)(ii).

(5) For Phase 2 vehicles, the GEM inputs described in paragraphs (b)(4)(i) through (v) of this section continue to apply. Note that the provisions related to vehicle speed limiters and automatic engine shutdown systems are available for vocational vehicles in Phase 2. The additional GEM inputs that apply for vocational vehicles and other tractor regulatory subcategories for demonstrating compliance with Phase 2 standards are as follows:

(i) Enter information from the engine manufacturer to describe the installed engine and its operating parameters as described in 40 CFR 1036.503 and 1037.520(f).

(ii) Enter information in accordance with 40 CFR 1037.520(g) for the vehicle and its operating parameters including:

(A) Transmission make, model and type;

(B) Drive axle configuration;

(C) Drive axle ratio, ka;

(D) GEM inputs associated with powertrain testing include powertrain family, transmission calibration identifier, test data from 40 CFR 1037.550, and the powertrain test configuration (dynamometer connected to transmission output or wheel hub).

(iii) Identify whether the manufacturer's vehicle has qualifying idle-reduction technologies, subject to the qualifying criteria in 40 and 1037.660 and enter values for stop start and neutral idle technologies as specified in 40 CFR 1037.520(h).

(iv) Manufacturers may use axle efficiency maps as described in 40 CFR 1037.560 and transmission efficiency maps as described in 40 CFR 1037.565 to replace the default values in GEM.

(v) Enter input values in GEM as follows to characterize the percentage CO2 emission reduction corresponding to certain technologies and vehicle configurations, or enter 0 as specified in 40 CFR 1037.520(j):

(A) Intelligent controls

(B) Accessory load

(C) Tire-pressure systems

(D) Extended-idle reduction

(E) Additional GEM inputs may apply as follows:

(1) Enter 1.7 and 0.9, respectively, for school buses and coach buses that have at least seven available forward gears.

(2) If the agencies approve an off-cycle technology under § 535.7(f) and 40 CFR 1037.610 in the form of an improvement factor, enter the improvement factor expressed as a percentage reduction in CO2 emissions. (Note: In the case of approved off-cycle technologies whose benefit is quantified as a g/ton-mile credit, apply the credit to the GEM result, not as a GEM input value.)

(3) Manufacturers may use values to characterize torque converters as inputs to GEM as specified in the procedure defined in 40 CFR 1037.570.

(4) Vocational vehicle manufacturers may optionally use values for neutral coasting in GEM as specified in 40 CFR 1037.520.

(vi) For vocational vehicles, determine the delta PTO emission result of the manufacturer's engine and hybrid power take-off system as described in 40 CFR 1037.540.

(vii) For vocational vehicles certified using the Regional duty cycle, enter ΔCdA values to account for using rear fairings and a reduced minimum frontal area as specified in 40 CFR 1037.520(m) and 1037.527.

(viii) For fuels other than those identified in GEM, perform the simulation by identifying the vehicle as being diesel-fueled if the engine is subject to the compression-ignition standard, or as being gasoline-fueled if the engine is subject to the spark-ignition standards. Correct the engine or powertrain fuel map for mass-specific net energy content as described in 40 CFR 1036.535(b).

(ix) A simplified versions of GEM applies for custom chassis vehicle subject § 535.5(b)(6) in accordance with 40 CFR 1037.520(a)(2)(ii).

(5) For Phase 2 vehicles, the GEM inputs described in paragraphs (b)(4)(i) through (v) of this section continue to apply. Note that the provisions related to vehicle speed limiters and automatic engine shutdown systems are available for vocational vehicles in Phase 2. The additional GEM inputs that apply for vocational vehicles and other tractor regulatory subcategories for demonstrating compliance with Phase 2 standards are as follows:

(i) Enter information from the engine manufacturer to describe the installed engine and its operating parameters as described in 40 CFR 1036.503 and 1037.520(f).

(ii) Enter information in accordance with 40 CFR 1037.520(g) for the vehicle and its operating parameters including:

(A) Transmission make, model and type;

(B) Drive axle configuration;

(C) Drive axle ratio, ka;

(D) GEM inputs associated with powertrain testing include powertrain family, transmission calibration identifier, test data from 40 CFR 1037.550, and the powertrain test configuration (dynamometer connected to transmission output or wheel hub).

(iii) Identify whether the manufacturer's vehicle has qualifying idle-reduction technologies, subject to the qualifying criteria in 40 and 1037.660 and enter values for stop start and neutral idle technologies as specified in 40 CFR 1037.520(h).

(iv) Manufacturers may use axle efficiency maps as described in 40 CFR 1037.560 and transmission efficiency maps as described in 40 CFR 1037.565 to replace the default values in GEM.

(v) Enter input values in GEM as follows to characterize the percentage CO2 emission reduction corresponding to certain technologies and vehicle configurations, or enter 0 as specified in 40 CFR 1037.520(j):

(A) Intelligent controls

(B) Accessory load

(C) Tire-pressure systems

(D) Extended-idle reduction

(E) Additional GEM inputs may apply as follows:

(1) Enter 1.7 and 0.9, respectively, for school buses and coach buses that have at least seven available forward gears.

(2) If the agencies approve an off-cycle technology under § 535.7(f) and 40 CFR 1037.610 in the form of an improvement factor, enter the improvement factor expressed as a percentage reduction in CO2 emissions. (Note: In the case of approved off-cycle technologies whose benefit is quantified as a g/ton-mile credit, apply the credit to the GEM result, not as a GEM input value.)

(3) Manufacturers may use values to characterize torque converters as inputs to GEM as specified in the procedure defined in 40 CFR 1037.570.

(4) Vocational vehicle manufacturers may optionally use values for neutral coasting in GEM as specified in 40 CFR 1037.520.

(vi) For vocational vehicles, determine the delta PTO emission result of the manufacturer's engine and hybrid power take-off system as described in 40 CFR 1037.540.

(vii) For vocational vehicles certified using the Regional duty cycle, enter ΔCdA values to account for using rear fairings and a reduced minimum frontal area as specified in 40 CFR 1037.520(m) and 1037.527.

(viii) For fuels other than those identified in GEM, perform the simulation by identifying the vehicle as being diesel-fueled if the engine is subject to the compression-ignition standard, or as being gasoline-fueled if the engine is subject to the spark-ignition standards. Correct the engine or powertrain fuel map for mass-specific net energy content as described in 40 CFR 1036.535(b).

(ix) A simplified versions of GEM applies for custom chassis vehicle subject § 535.5(b)(6) in accordance with 40 CFR 1037.520(a)(2)(ii).

(5) For Phase 2 vehicles, the GEM inputs described in paragraphs (b)(4)(i) through (v) of this section continue to apply. Note that the provisions related to vehicle speed limiters and automatic engine shutdown systems are available for vocational vehicles in Phase 2. The additional GEM inputs that apply for vocational vehicles and other tractor regulatory subcategories for demonstrating compliance with Phase 2 standards are as follows:

(i) Enter information from the engine manufacturer to describe the installed engine and its operating parameters as described in 40 CFR 1036.503 and 1037.520(f).

(ii) Enter information in accordance with 40 CFR 1037.520(g) for the vehicle and its operating parameters including:

(A) Transmission make, model and type;

(B) Drive axle configuration;

(C) Drive axle ratio, ka;

(D) GEM inputs associated with powertrain testing include powertrain family, transmission calibration identifier, test data from 40 CFR 1037.550, and the powertrain test configuration (dynamometer connected to transmission output or wheel hub).

(iii) Identify whether the manufacturer's vehicle has qualifying idle-reduction technologies, subject to the qualifying criteria in 40 and 1037.660 and enter values for stop start and neutral idle technologies as specified in 40 CFR 1037.520(h).

(iv) Manufacturers may use axle efficiency maps as described in 40 CFR 1037.560 and transmission efficiency maps as described in 40 CFR 1037.565 to replace the default values in GEM.

(v) Enter input values in GEM as follows to characterize the percentage CO2 emission reduction corresponding to certain technologies and vehicle configurations, or enter 0 as specified in 40 CFR 1037.520(j):

(A) Intelligent controls

(B) Accessory load

(C) Tire-pressure systems

(D) Extended-idle reduction

(E) Additional GEM inputs may apply as follows:

(1) Enter 1.7 and 0.9, respectively, for school buses and coach buses that have at least seven available forward gears.

(2) If the agencies approve an off-cycle technology under § 535.7(f) and 40 CFR 1037.610 in the form of an improvement factor, enter the improvement factor expressed as a percentage reduction in CO2 emissions. (Note: In the case of approved off-cycle technologies whose benefit is quantified as a g/ton-mile credit, apply the credit to the GEM result, not as a GEM input value.)

(3) Manufacturers may use values to characterize torque converters as inputs to GEM as specified in the procedure defined in 40 CFR 1037.570.

(4) Vocational vehicle manufacturers may optionally use values for neutral coasting in GEM as specified in 40 CFR 1037.520.

(vi) For vocational vehicles, determine the delta PTO emission result of the manufacturer's engine and hybrid power take-off system as described in 40 CFR 1037.540.

(vii) For vocational vehicles certified using the Regional duty cycle, enter ΔCdA values to account for using rear fairings and a reduced minimum frontal area as specified in 40 CFR 1037.520(m) and 1037.527.

(viii) For fuels other than those identified in GEM, perform the simulation by identifying the vehicle as being diesel-fueled if the engine is subject to the compression-ignition standard, or as being gasoline-fueled if the engine is subject to the spark-ignition standards. Correct the engine or powertrain fuel map for mass-specific net energy content as described in 40 CFR 1036.535(b).

(ix) A simplified versions of GEM applies for custom chassis vehicle subject § 535.5(b)(6) in accordance with 40 CFR 1037.520(a)(2)(ii).