Subpart C - Procedures for Calculating Fuel Economy and Carbon-Related Exhaust Emission Values

§600.206-12 Calculation and use of FTP-based and HFET-based fuel economy, CO 2 emissions, and carbon-related exhaust emission values for vehicle configurations.

(a) Fuel economy, CO ₂ emissions, and carbon-related exhaust emissions values determined for each vehicle under §600.113-08(a) and (b) and as approved in §600.008(c), are used to determine FTP-based city, HFET-based highway, and combined FTP/Highway-based fuel economy, CO ₂ emissions, and carbon-related exhaust emission values for each vehicle configuration for which data are available. Note that fuel economy for some alternative fuel vehicles may mean miles per gasoline gallon equivalent and/or miles per unit of fuel consumed. For example, electric vehicles will determine miles per kilowatt-hour in addition to miles per gasoline gallon equivalent, and fuel cell vehicles will determine miles per kilogram of hydrogen.

§600.207-12 Calculation and use of vehicle-specific 5-cycle-based fuel economy and CO emission values for vehicle configurations.

(a) Fuel economy and CO ₂ emission values determined for each vehicle under §600.114 and as approved in §600.008(c), are used to determine vehicle-specific 5-cycle city and highway fuel economy and CO ₂ emission values for each vehicle configuration for which data are available.

(1) If only one set of 5-cycle city and highway fuel economy and CO ₂ emission values is accepted for a vehicle configuration, these values, where fuel economy is rounded to the nearest 0.0001 of a mile per gallon and the CO ₂ emission value in grams per mile is rounded to the nearest tenth of a gram per mile, comprise the city and highway fuel economy and CO ₂ emission values for that configuration. Note that the appropriate vehicle-specific CO ₂ values for fuel economy labels based on 5-cycle testing with E10 test fuel are adjusted as described in §600.114-12.

(2) If more than one set of 5-cycle city and highway fuel economy and CO ₂ emission values are accepted for a vehicle configuration:

(i) All data shall be grouped according to the subconfiguration for which the data were generated using sales projections supplied in accordance with §600.209-12(a)(3).

(ii) Within each subconfiguration of data, all fuel economy values are harmonically averaged and rounded to the nearest 0.0001 of a mile per gallon in order to determine 5-cycle city and highway fuel economy values for each subconfiguration at which the vehicle configuration was tested, and all CO ₂ emissions values are arithmetically averaged and rounded to the nearest tenth of gram per mile to determine 5-cycle city and highway CO ₂ emission values for each subconfiguration at which the vehicle configuration was tested. Note that the appropriate vehicle-specific CO ₂ values for fuel economy labels based on 5-cycle testing with E10 test fuel are adjusted as described in §600.114-12.

(iii) All 5-cycle city fuel economy values and all 5-cycle highway fuel economy values calculated in paragraph (a)(2)(ii) of this section are (separately for city and highway) averaged in proportion to the sales fraction (rounded to the nearest 0.0001) within the vehicle configuration (as provided to the Administrator by the manufacturer) of vehicles of each tested subconfiguration. The resultant values, rounded to the nearest 0.0001 mile per gallon, are the 5-cycle city and 5-cycle highway fuel economy values for the vehicle configuration.

(iv) All 5-cycle city CO ₂ emission values and all 5-cycle highway CO ₂ emission values calculated in paragraph (a)(2)(ii) of this section are (separately for city and highway) averaged in proportion to the sales fraction (rounded to the nearest 0.0001) within the vehicle configuration (as provided to the Administrator by the manufacturer) of vehicles of each tested subconfiguration. The resultant values, rounded to the nearest 0.1 grams per mile, are the 5-cycle city and 5-cycle highway CO ₂ emission values for the vehicle configuration.

(3) [Reserved]

(4) For alcohol dual fuel automobiles and natural gas dual fuel automobiles, the procedures of paragraphs (a)(1) and (2) of this section shall be used to calculate two separate sets of 5-cycle city and highway fuel economy and CO ₂ emission values for each configuration.

(i) Calculate the 5-cycle city and highway fuel economy and CO ₂ emission values from the tests performed using gasoline or diesel test fuel.

(ii) Calculate the 5-cycle city and highway fuel economy and CO ₂ emission values from the tests performed using alcohol or natural gas test fuel, if 5-cycle testing has been performed. Otherwise, the procedure in §600.210-12(a)(3) or (b)(3) applies.

(b) If only one equivalent petroleum-based fuel economy value exists for an electric configuration, that value, rounded to the nearest tenth of a mile per gallon, will comprise the petroleum-based 5-cycle fuel economy for that configuration.

(c) If more than one equivalent petroleum-based 5-cycle fuel economy value exists for an electric vehicle configuration, all values for that vehicle configuration are harmonically averaged and rounded to the nearest 0.0001 mile per gallon for that configuration.

[76 FR 39551, July 6, 2011; 89 FR 28208, Apr. 18, 2024]

§600.208-12 Calculation of FTP-based and HFET-based fuel economy, CO 2 emissions, and carbon-related exhaust emissions for a model type.

(a) Fuel economy, CO₂ emissions, and carbon-related exhaust emissions for a base level are calculated from vehicle configuration fuel economy, CO₂ emissions, and carbon-related exhaust emissions as determined in §600.206-12(a), (b), or (c) as applicable, for low-altitude tests.

(1) If the Administrator determines that automobiles intended for sale in the State of California and in section 177 states are likely to exhibit significant differences in fuel economy, CO₂ emissions, and carbon-related exhaust emissions from those intended for sale in other states, she will calculate fuel economy, CO₂ emissions, and carbon-related exhaust emissions for each base level for vehicles intended for sale in California and in section 177 states and for each base level for vehicles intended for sale in the rest of the states.

(2) In order to highlight the fuel efficiency, CO₂ emissions, and carbon-related exhaust emissions of certain designs otherwise included within a model type, a manufacturer may wish to subdivide a model type into one or more additional model types. This is accomplished by separating subconfigurations from an existing base level and placing them into a new base level. The new base level is identical to the existing base level except that it shall be considered, for the purposes of this paragraph, as containing a new basic engine. The manufacturer will be permitted to designate such new basic engines and base level(s) if:

(i) Each additional model type resulting from division of another model type has a unique car line name and that name appears on the label and on the vehicle bearing that label;

(ii) The subconfigurations included in the new base levels are not included in any other base level which differs only by basic engine (i.e., they are not included in the calculation of the original base level fuel economy values); and

(iii) All subconfigurations within the new base level are represented by test data in accordance with §600.010(c)(1)(iii).

(3) The manufacturer shall supply total model year sales projections for each car line/vehicle subconfiguration combination.

(i) Sales projections must be supplied separately for each car line-vehicle subconfiguration intended for sale in California and each car line/vehicle subconfiguration intended for sale in the rest of the states if required by the Administrator under paragraph (a)(1) of this section.

(ii) Manufacturers shall update sales projections at the time any model type value is calculated for a label value.

(iii) The provisions of paragraph (a)(3) of this section may be satisfied by providing an amended application for certification, as described in §86.1844 of this chapter.

(4) Vehicle configuration fuel economy, CO ₂ emissions, and carbon-related exhaust emissions, as determined in §600.206-12(a), (b) or (c), as applicable, are grouped according to base level.

(i) If only one vehicle configuration within a base level has been tested, the fuel economy, CO ₂ emissions, and carbon-related exhaust emissions from that vehicle configuration will constitute the fuel economy, CO ₂ emissions, and carbon-related exhaust emissions for that base level. Note that the appropriate vehicle subconfiguration CO ₂ values for fuel economy labels based on testing with E10 test fuel are adjusted as referenced in §600.206-12(a)(2)(iii); those values are used to calculate the base level CO ₂ values in this paragraph (a)(4)(i).

(ii) If more than one vehicle configuration within a base level has been tested, the vehicle configuration fuel economy values are harmonically averaged in proportion to the respective sales fraction (rounded to the nearest 0.0001) of each vehicle configuration and the resultant fuel economy value rounded to the nearest 0.0001 mile per gallon; and the vehicle configuration CO ₂ emissions and carbon-related exhaust emissions are arithmetically averaged in proportion to the respective sales fraction (rounded to the nearest 0.0001) of each vehicle configuration and the resultant carbon-related exhaust emission value rounded to the nearest tenth of a gram per mile. Note that the appropriate vehicle subconfiguration CO ₂ values for fuel economy labels based on testing with E10 test fuel are adjusted as referenced in §600.206-12(a)(2)(iii); those values are used to calculate the base level CO ₂ values in this paragraph (a)(4)(ii).

(5) The procedure specified in paragraph (a)(1) through (4) of this section will be repeated for each base level, thus establishing city, highway, and combined fuel economy, CO₂ emissions, and carbon-related exhaust emissions for each base level.

(6) [Reserved]

(7) For alcohol dual fuel automobiles and natural gas dual fuel automobiles, the procedures of paragraphs (a)(1) through (6) of this section shall be used to calculate two separate sets of city, highway, and combined fuel economy, CO₂ emissions, and carbon-related exhaust emissions for each base level.

(i) Calculate the city, highway, and combined fuel economy, CO₂ emissions, and carbon-related exhaust emissions from the tests performed using gasoline or diesel test fuel.

(ii) Calculate the city, highway, and combined fuel economy, CO₂ emissions, and carbon-related exhaust emissions from the tests performed using alcohol or natural gas test fuel.

(b) For each model type, as determined by the Administrator, a city, highway, and combined fuel economy value, CO₂ emission value, and a carbon-related exhaust emission value will be calculated by using the projected sales and values for fuel economy, CO₂ emissions, and carbon-related exhaust emissions for each base level within the model type. Separate model type calculations will be done based on the vehicle configuration fuel economy, CO₂ emissions, and carbon-related exhaust emissions as determined in §600.206-12(a), (b) or (c), as applicable.

(1) If the Administrator determines that automobiles intended for sale in the State of California and in section 177 states are likely to exhibit significant differences in fuel economy, CO₂ emissions, and carbon-related exhaust emissions from those intended for sale in other states, he or she will calculate values for fuel economy, CO₂ emissions, and carbon-related exhaust emissions for each model type for vehicles intended for sale in California and in section 177 states and for each model type for vehicles intended for sale in the rest of the states.

(2) The sales fraction for each base level is calculated by dividing the projected sales of the base level within the model type by the projected sales of the model type and rounding the quotient to the nearest 0.0001.

(3)(i) The FTP-based city fuel economy values of the model type (calculated to the nearest 0.0001 mpg) are determined by dividing one by a sum of terms, each of which corresponds to a base level and which is a fraction determined by dividing:

(A) The sales fraction of a base level; by

(B) The FTP-based city fuel economy value for the respective base level.

(ii) The FTP-based city carbon-related exhaust emission value of the model type (calculated to the nearest gram per mile) are determined by a sum of terms, each of which corresponds to a base level and which is a product determined by multiplying:

(A) The sales fraction of a base level; by

(B) The FTP-based city carbon-related exhaust emission value for the respective base level.

(iii) The FTP-based city CO₂ emissions of the model type (calculated to the nearest gram per mile) are determined by a sum of terms, each of which corresponds to a base level and which is a product determined by multiplying:

(A) The sales fraction of a base level; by

(B) The FTP-based city CO₂ emissions for the respective base level.

(C) Note that the appropriate base level CO ₂ values for fuel economy labels based on testing with E10 test fuel are adjusted as referenced in paragraph (a)(4)(i) and (ii) of this section; those values are used to calculate the model type FTP-based city CO ₂ values in this paragraph (b)(3)(iii).

(4) The procedure specified in paragraph (b)(3) of this section is repeated in an analogous manner to determine the highway and combined fuel economy, CO₂ emissions, and carbon-related exhaust emissions for the model type.

(5) For alcohol dual fuel automobiles and natural gas dual fuel automobiles, the procedures of paragraphs (b)(1) through (4) of this section shall be used to calculate two separate sets of city, highway, and combined fuel economy values and two separate sets of city, highway, and combined CO₂ and carbon-related exhaust emission values for each model type.

(i) Calculate the city, highway, and combined fuel economy, CO₂ emissions, and carbon-related exhaust emission values from the tests performed using gasoline or diesel test fuel.

(ii) Calculate the city, highway, and combined fuel economy, CO₂ emissions, and carbon-related exhaust emission values from the tests performed using alcohol or natural gas test fuel.

[76 FR 39552, July 6, 2011, as amended at 81 FR 74002, Oct. 25, 2016; 89 FR 28207, Apr. 18, 2024]

§600.209-12 Calculation of vehicle-specific 5-cycle fuel economy and CO 2 emission values for a model type.

(a) Base level. 5-cycle fuel economy and CO ₂ emission values for a base level are calculated from vehicle configuration 5-cycle fuel economy and CO ₂ emission values as determined in §600.207 for low-altitude tests. Note that the appropriate vehicle-specific CO ₂ values for fuel economy labels based on 5-cycle testing with E10 test fuel are adjusted as described in §600.114-12.

(1) If the Administrator determines that automobiles intended for sale in the State of California are likely to exhibit significant differences in fuel economy and CO₂ emissions from those intended for sale in other states, he will calculate fuel economy and CO₂ emission values for each base level for vehicles intended for sale in California and for each base level for vehicles intended for sale in the rest of the states.

(2) In order to highlight the fuel efficiency and CO₂ emissions of certain designs otherwise included within a model type, a manufacturer may wish to subdivide a model type into one or more additional model types. This is accomplished by separating subconfigurations from an existing base level and placing them into a new base level. The new base level is identical to the existing base level except that it shall be considered, for the purposes of this paragraph, as containing a new basic engine. The manufacturer will be permitted to designate such new basic engines and base level(s) if:

(i) Each additional model type resulting from division of another model type has a unique car line name and that name appears on the label and on the vehicle bearing that label;

(ii) The subconfigurations included in the new base levels are not included in any other base level which differs only by basic engine (i.e., they are not included in the calculation of the original base level fuel economy values); and

(iii) All subconfigurations within the new base level are represented by test data in accordance with §600.010(c)(i)(ii).

(3) The manufacturer shall supply total model year sales projections for each car line/vehicle subconfiguration combination.

(i) Sales projections must be supplied separately for each car line-vehicle subconfiguration intended for sale in California and each car line/vehicle subconfiguration intended for sale in the rest of the states if required by the Administrator under paragraph (a)(1) of this section.

(ii) Manufacturers shall update sales projections at the time any model type value is calculated for a label value.

(iii) The provisions of this paragraph (a)(3) may be satisfied by providing an amended application for certification, as described in §86.1844 of this chapter.

(4) 5-cycle vehicle configuration fuel economy and CO₂ emission values, as determined in §600.207-12(a), (b), or (c), as applicable, are grouped according to base level.

(i) If only one vehicle configuration within a base level has been tested, the fuel economy and CO₂ emission values from that vehicle configuration constitute the fuel economy and CO₂ emission values for that base level.

(ii) If more than one vehicle configuration within a base level has been tested, the vehicle configuration fuel economy values are harmonically averaged in proportion to the respective sales fraction (rounded to the nearest 0.0001) of each vehicle configuration and the resultant fuel economy value rounded to the nearest 0.0001 mile per gallon.

(iii) If more than one vehicle configuration within a base level has been tested, the vehicle configuration CO₂ emission values are arithmetically averaged in proportion to the respective sales fraction (rounded to the nearest 0.0001) of each vehicle configuration and the resultant CO₂ emission value rounded to the nearest 0.1 gram per mile.

(5) The procedure specified in §600.209-12(a) will be repeated for each base level, thus establishing city and highway fuel economy and CO₂ emission values for each base level.

(6) [Reserved]

(7) For alcohol dual fuel automobiles and natural gas dual fuel automobiles, the procedures of paragraphs (a)(1) through (6) of this section shall be used to calculate two separate sets of city, highway, and combined fuel economy and CO₂ emission values for each base level.

(i) Calculate the city and highway fuel economy and CO₂ emission values from the tests performed using gasoline or diesel test fuel.

(ii) If 5-cycle testing was performed on the alcohol or natural gas test fuel, calculate the city and highway fuel economy and CO₂ emission values from the tests performed using alcohol or natural gas test fuel.

(b) Model type. For each model type, as determined by the Administrator, city and highway fuel economy and CO ₂ emissions values will be calculated by using the projected sales and fuel economy and CO ₂ emission values for each base level within the model type. Separate model type calculations will be done based on the vehicle configuration fuel economy and CO ₂ emission values as determined in §600.207-12, as applicable. Note that the appropriate vehicle-specific CO ₂ values for fuel economy labels based on 5-cycle testing with E10 test fuel are adjusted as described in §600.114-12.

(1) If the Administrator determines that automobiles intended for sale in the State of California are likely to exhibit significant differences in fuel economy and CO₂ emissions from those intended for sale in other states, he will calculate fuel economy and CO₂ emission values for each model type for vehicles intended for sale in California and for each model type for vehicles intended for sale in the rest of the states.

(2) The sales fraction for each base level is calculated by dividing the projected sales of the base level within the model type by the projected sales of the model type and rounding the quotient to the nearest 0.0001.

(3)(i) The 5-cycle city fuel economy values of the model type (calculated to the nearest 0.0001 mpg) are determined by dividing one by a sum of terms, each of which corresponds to a base level and which is a fraction determined by dividing:

(A) The sales fraction of a base level; by

(B) The 5-cycle city fuel economy value for the respective base level.

(ii) The 5-cycle city CO₂ emissions of the model type (calculated to the nearest tenth of a gram per mile) are determined by a sum of terms, each of which corresponds to a base level and which is a product determined by multiplying:

(A) The sales fraction of a base level; by

(B) The 5-cycle city CO₂ emissions for the respective base level.

(4) The procedure specified in paragraph (b)(3) of this section is repeated in an analogous manner to determine the highway and combined fuel economy and CO₂ emission values for the model type.

(5) For alcohol dual fuel automobiles and natural gas dual fuel automobiles the procedures of paragraphs (b)(1) through (4) of this section shall be used to calculate two separate sets of city and highway fuel economy and CO₂ emission values for each model type.

(i) Calculate the city and highway fuel economy and CO₂ emission values from the tests performed using gasoline or diesel test fuel.

(ii) Calculate the city, highway, and combined fuel economy and CO₂ emission values from the tests performed using alcohol or natural gas test fuel, if 5-cycle testing was performed on the alcohol or natural gas test fuel. Otherwise, the procedure in §600.210-12(a)(3) or (b)(3) applies.

[76 FR 39553, July 6, 2011; 89 FR 28209, Apr. 18, 2024]

§600.210-12 Calculation of fuel economy and CO 2 emission values for labeling.

(a) General labels. Except as specified in paragraphs (d) and (e) of this section, fuel economy and CO ₂ emissions for general labels may be determined by one of two methods. The first is based on vehicle-specific model-type 5-cycle data as determined in §600.209-12(b). This method is available for all vehicles and is required for vehicles that do not qualify for the second method as described in §600.115 (other than electric vehicles). The second method, the derived 5-cycle method, determines fuel economy and CO ₂ emissions values from the FTP and HFET tests using equations that are derived from vehicle-specific 5-cycle model type data, as determined in paragraph (a)(2) of this section. Manufacturers may voluntarily lower fuel economy (MPG) values and raise CO ₂ values if they determine that the label values from any method are not representative of the in-use fuel economy and CO ₂ emissions for that model type, but only if the manufacturer changes both the MPG values and the CO ₂ value and revises any other affected label value accordingly for a model type (including but not limited to the fuel economy 1-10 rating, greenhouse gas 1-10 rating, annual fuel cost, 5-year fuel cost information). Similarly, for any electric vehicles and plug-in hybrid electric vehicles, manufacturers may voluntarily lower the fuel economy (MPGe) and raise the energy consumption (kW-hr/100 mile) values if they determine that the label values are not representative of the in-use fuel economy, energy consumption, and CO ₂ emissions for that model type, but only if the manufacturer changes both the MPGe and the energy consumption value and revises any other affected label value accordingly for a model type. Manufacturers may voluntarily lower the value for electric driving range if they determine that the label values are not representative of the in-use electric driving range.

(1) Vehicle-specific 5-cycle labels. The city and highway model type fuel economy determined in §600.209-12(b), rounded to the nearest mpg, and the city and highway model type CO₂ emissions determined in §600.209-12(b), rounded to the nearest gram per mile, comprise the fuel economy and CO₂ emission values for general fuel economy labels, or, alternatively;

(2) Derived 5-cycle labels. Derived 5-cycle city and highway label values are determined according to the following method:

(i)(A) For each model type, determine the derived five-cycle city fuel economy using the following equation and coefficients determined by the Administrator:

Where:

City Intercept = Intercept determined by the Administrator based on historic vehicle-specific 5-cycle city fuel economy data.

City Slope = Slope determined by the Administrator based on historic vehicle-specific 5-cycle city fuel economy data.

MT FTP FE = the model type FTP-based city fuel economy determined under §600.208-12(b), rounded to the nearest 0.0001 mpg.

(B) For each model type, determine the derived five-cycle city CO ₂ emissions using the following equation and coefficients determined by the Administrator:

Derived 5-cycle City CO ₂ = City Intercept · A + City Slope · MT FTP CO ₂

Where:

City Intercept = Intercept determined by the Administrator based on historic vehicle-specific 5-cycle city fuel economy data.

A = 8,887 for gasoline-fueled vehicles, 10,180 for diesel-fueled vehicles, or an appropriate value specified by the Administrator for other fuels.

City Slope = Slope determined by the Administrator based on historic vehicle-specific 5-cycle city fuel economy data.

MT FTP CO ₂ = the model type FTP-based city CO ₂ emissions determined under §600.208-12(b), rounded to the nearest 0.1 grams per mile. Note that the appropriate MT FTP CO ₂ input values for fuel economy labels based on testing with E10 test fuel are adjusted as referenced in §600.208-12(b)(3)(iii).

(ii)(A) For each model type, determine the derived five-cycle highway fuel economy using the equation below and coefficients determined by the Administrator:

Where:

Highway Intercept = Intercept determined by the Administrator based on historic vehicle-specific 5-cycle highway fuel economy data.

Highway Slope = Slope determined by the Administrator based on historic vehicle-specific 5-cycle highway fuel economy data.

MT HFET FE = the model type highway fuel economy determined under §600.208-12(b), rounded to the nearest 0.0001 mpg.

(B) For each model type, determine the derived five-cycle highway CO ₂ emissions using the equation below and coefficients determined by the Administrator:

Derived 5-cycle Highway CO = Highway Intercept · A + Highway Slope · MT HFET CO

Where:

Highway Intercept = Intercept determined by the Administrator based on historic vehicle-specific 5-cycle highway fuel economy data.

A = 8,887 for gasoline-fueled vehicles, 10,180 for diesel-fueled vehicles, or an appropriate value specified by the Administrator for other fuels.

Highway Slope = Slope determined by the Administrator based on historic vehicle-specific 5-cycle highway fuel economy data.

MT HFET CO = the model type highway CO ₂ emissions determined under §600.208-12(b), rounded to the nearest 0.1 grams per mile. Note that the appropriate the MT HFET CO ₂ input values for fuel economy labels based on testing with E10 test fuel are adjusted as referenced in §600.208-12(b)(3)(iii) and (b)(4).

(iii) Unless and until superseded by written guidance from the Administrator, the following intercepts and slopes shall be used in the equations in paragraphs (a)(2)(i) and (ii) of this section:

City Intercept = 0.004091.

City Slope = 1.1601.

Highway Intercept = 0.003191.

Highway Slope = 1.2945.

(iv) The Administrator will periodically update the slopes and intercepts through guidance and will determine the model year that the new coefficients must take effect. The Administrator will issue guidance no later than six months prior to the earliest starting date of the effective model year (e.g., for 2011 models, the earliest start of the model year is January 2, 2010, so guidance would be issued by July 1, 2009.) Until otherwise instructed by written guidance from the Administrator, manufacturers must use the coefficients that are currently in effect.

(3) General alternate fuel economy and CO₂emissions label values for dual fuel vehicles. (i)(A) City and Highway fuel economy label values for dual fuel alcohol-based and natural gas vehicles when using the alternate fuel are separately determined by the following calculation:

Where:

FE_alt = The unrounded FTP-based model-type city or HFET-based model-type highway fuel economy from the alternate fuel, as determined in §600.208-12(b)(5)(ii).

5cycle FE_gas = The unrounded vehicle-specific or derived 5-cycle model-type city or highway fuel economy, as determined in paragraph (a)(1) or (2) of this section.

FE_gas = The unrounded FTP-based city or HFET-based model type highway fuel economy from gasoline (or diesel), as determined in §600.208-12(b)(5)(i).

The result, rounded to the nearest whole number, is the alternate fuel label value for dual fuel vehicles.

(B) City and Highway CO₂ label values for dual fuel alcohol-based and natural gas vehicles when using the alternate fuel are separately determined by the following calculation:

Where:

CO2_alt = The unrounded FTP-based model-type city or HFET-based model-type CO₂ emissions value from the alternate fuel, as determined in §600.208-12(b)(5)(ii).

5cycle CO2_gas = The unrounded vehicle-specific or derived 5-cycle model-type city or highway CO₂ emissions value, as determined in paragraph (a)(1) or (2) of this section.

CO2_gas = The unrounded FTP-based city or HFET-based model type highway CO₂ emissions value from gasoline (or diesel), as determined in §600.208-12(b)(5)(i).

The result, rounded to the nearest whole number, is the alternate fuel CO₂ emissions label value for dual fuel vehicles.

(ii) Optionally, if complete 5-cycle testing has been performed using the alternate fuel, the manufacturer may choose to use the alternate fuel label city or highway fuel economy and CO₂ emission values determined in §600.209-12(b)(5)(ii), rounded to the nearest whole number.

(4) General alternate fuel economy and CO₂emissions label values for electric vehicles. Determine FTP-based city and HFET-based highway fuel economy label values for electric vehicles as described in §600.116. Convert W-hour/mile results to miles per kW-hr and miles per gasoline gallon equivalent. CO₂ label information is based on tailpipe emissions only, so CO₂ emissions from electric vehicles are assumed to be zero.

(5) General alternate fuel economy and CO₂emissions label values for fuel cell vehicles. Determine FTP-based city and HFET-based highway fuel economy label values for fuel cell vehicles using procedures specified by the Administrator. Convert kilograms of hydrogen/mile results to miles per kilogram of hydrogen and miles per gasoline gallon equivalent. CO₂ label information is based on tailpipe emissions only, so CO₂ emissions from fuel cell vehicles are assumed to be zero.

(b) Specific labels. Except as specified in paragraphs (d) and (e) of this section, fuel economy and CO₂ emissions for specific labels may be determined by one of two methods. The first is based on vehicle-specific configuration 5-cycle data as determined in §600.207. This method is available for all vehicles and is required for vehicles that do not qualify for the second method as described in §600.115 (other than electric vehicles). The second method, the derived 5-cycle method, determines fuel economy and CO₂ emissions values from the FTP and HFET tests using equations that are derived from vehicle-specific 5-cycle configuration data, as determined in paragraph (b)(2) of this section. Manufacturers may voluntarily lower fuel economy values and raise CO₂ values if they determine that the label values from either method are not representative of the fuel economy or CO₂ emissions for that model type.

(1) Vehicle-specific 5-cycle labels. The city and highway configuration fuel economy determined in §600.207, rounded to the nearest mpg, and the city and highway configuration CO₂ emissions determined in §600.207, rounded to the nearest gram per mile, comprise the fuel economy and CO₂ emission values for specific fuel economy labels, or, alternatively;

(2) Derived 5-cycle labels. Specific city and highway label values from derived 5-cycle are determined according to the following method:

(i)(A) Determine the derived five-cycle city fuel economy of the configuration using the equation below and coefficients determined by the Administrator:

Where:

City Intercept = Intercept determined by the Administrator based on historic vehicle-specific 5-cycle city fuel economy data.

City Slope = Slope determined by the Administrator based on historic vehicle-specific 5-cycle city fuel economy data.

Config FTP FE = the configuration FTP-based city fuel economy determined under §600.206, rounded to the nearest 0.0001 mpg.

(B) Determine the derived five-cycle city CO ₂ emissions of the configuration using the equation below and coefficients determined by the Administrator:

Derived 5-cycle City CO ₂ = City Intercept + City Slope ·Config FTP CO ₂

Where:

City Intercept = Intercept determined by the Administrator based on historic vehicle-specific 5-cycle city fuel economy data.

City Slope = Slope determined by the Administrator based on historic vehicle-specific 5-cycle city fuel economy data.

Config FTP CO ₂ = the configuration FTP-based city CO ₂ emissions determined under §600.206, rounded to the nearest 0.1 grams per mile. Note that the appropriate Config FTP CO ₂ input values for fuel economy labels based on testing with E10 test fuel are adjusted as referenced in §600.206-12(a)(2)(iii).

(ii)(A) Determine the derived five-cycle highway fuel economy of the configuration using the equation below and coefficients determined by the Administrator:

Where:

Highway Intercept = Intercept determined by the Administrator based on historic vehicle-specific 5-cycle highway fuel economy data.

Highway Slope = Slope determined by the Administrator based on historic vehicle-specific 5-cycle highway fuel economy data.

Config HFET FE = the configuration highway fuel economy determined under §600.206, rounded to the nearest tenth.

(B) Determine the derived five-cycle highway CO ₂ emissions of the configuration using the equation below and coefficients determined by the Administrator:

Derived 5-cycle city Highway CO = Highway Intercept + Highway Slope · Config HFET CO

Where:

Highway Intercept = Intercept determined by the Administrator based on historic vehicle-specific 5-cycle highway fuel economy data.

Highway Slope = Slope determined by the Administrator based on historic vehicle-specific 5-cycle highway fuel economy data.

Config HFET CO = the configuration highway fuel economy determined under §600.206, rounded to the nearest tenth. Note that the appropriate Config HFET CO ₂ input values for fuel economy labels based on testing with E10 test fuel are adjusted as referenced in §600.206-12(a)(2)(iii).

(iii) The slopes and intercepts of paragraph (a)(2)(iii) of this section apply.

(3) Specific alternate fuel economy and CO₂emissions label values for dual fuel vehicles. (i)(A) Specific city and highway fuel economy label values for dual fuel alcohol-based and natural gas vehicles when using the alternate fuel are separately determined by the following calculation:

Where:

FE_alt = The unrounded FTP-based configuration city or HFET-based configuration highway fuel economy from the alternate fuel, as determined in §600.206.

5cycle FE_gas = The unrounded vehicle-specific or derived 5-cycle configuration city or highway fuel economy as determined in paragraph (b)(1) or (2) of this section.

FE_gas = The unrounded FTP-based city or HFET-based configuration highway fuel economy from gasoline, as determined in §600.206.

The result, rounded to the nearest whole number, is the alternate fuel label value for dual fuel vehicles.

(B) Specific city and highway CO₂ emission label values for dual fuel alcohol-based and natural gas vehicles when using the alternate fuel are separately determined by the following calculation:

Where:

CO2_alt = The unrounded FTP-based configuration city or HFET-based configuration highway CO₂ emissions value from the alternate fuel, as determined in §600.206.

5cycle CO2_gas = The unrounded vehicle-specific or derived 5-cycle configuration city or highway CO₂ emissions value as determined in paragraph (b)(1) or (b)(2) of this section.

CO2_gas = The unrounded FTP-based city or HFET-based configuration highway CO₂ emissions value from gasoline, as determined in §600.206.

The result, rounded to the nearest whole number, is the alternate fuel CO₂ emissions label value for dual fuel vehicles.

(ii) Optionally, if complete 5-cycle testing has been performed using the alternate fuel, the manufacturer may choose to use the alternate fuel label city or highway fuel economy and CO₂ emission values determined in §600.207-12(a)(4)(ii), rounded to the nearest whole number.

(4) Specific alternate fuel economy and CO₂emissions label values for electric vehicles. Determine FTP-based city and HFET-based highway fuel economy label values for electric vehicles as described in §600.116. Determine these values by running the appropriate repeat test cycles. Convert W-hour/mile results to miles per kW-hr and miles per gasoline gallon equivalent. CO₂ label information is based on tailpipe emissions only, so CO₂ emissions from electric vehicles are assumed to be zero.

(5) Specific alternate fuel economy and CO₂emissions label values for fuel cell vehicles. Determine FTP-based city and HFET-based highway fuel economy label values for fuel cell vehicles using procedures specified by the Administrator. Convert kilograms of hydrogen/mile results to miles per kilogram of hydrogen and miles per gasoline gallon equivalent. CO₂ label information is based on tailpipe emissions only, so CO₂ emissions from fuel cell vehicles are assumed to be zero.

(c) Calculating combined fuel economy. (1) For the purposes of calculating the combined fuel economy for a model type, to be used in displaying on the label and for determining annual fuel costs under subpart D of this part, the manufacturer shall use one of the following procedures:

(i) For gasoline-fueled, diesel-fueled, alcohol-fueled, and natural gas-fueled automobiles, and for dual fuel automobiles that can operate on gasoline or diesel fuel, harmonically average the unrounded city and highway fuel economy values, determined in paragraphs (a)(1) or (2) of this section and (b)(1) or (2) of this section, weighted 0.55 and 0.45 respectively. Round the result to the nearest whole mpg. (An example of this calculation procedure appears in Appendix II of this part).

(ii) For alcohol dual fuel and natural gas dual fuel automobiles operated on the alternate fuel, harmonically average the unrounded city and highway values from the tests performed using the alternative fuel as determined in paragraphs (a)(3) and (b)(3) of this section, weighted 0.55 and 0.45 respectively. Round the result to the nearest whole mpg.

(iii) For electric vehicles, calculate the combined fuel economy, in miles per kW-hr and miles per gasoline gallon equivalent, by harmonically averaging the unrounded city and highway values, weighted 0.55 and 0.45 respectively. Round miles per kW-hr to the nearest 0.001 and round miles per gasoline gallon equivalent to the nearest whole number.

(iv) For plug-in hybrid electric vehicles, calculate a combined fuel economy value, in miles per gasoline gallon equivalent as follows:

(A) Determine city and highway fuel economy values for vehicle operation after the battery has been fully discharged (“gas only operation” or “charge-sustaining mode”) as described in paragraphs (a) and (b) of this section.

(B) Determine city and highway fuel economy values for vehicle operation starting with a full battery charge (“all-electric operation” or “gas plus electric operation”, as appropriate, or “charge-depleting mode”) as described in §600.116. For battery energy, convert W-hour/mile results to miles per gasoline gallon equivalent or miles per diesel gallon equivalent, as applicable. Note that you must also express battery-based fuel economy values in miles per kW-hr for calculating annual fuel cost as described in §600.311.

(C) Calculate a composite city fuel economy value and a composite highway fuel economy value by combining the separate results for battery and engine operation using the procedures described in §600.116). Apply the derived 5-cycle adjustment to these composite values. Use these values to calculate the vehicle's combined fuel economy as described in paragraph (c)(1)(i) of this section.

(v) For fuel cell vehicles, calculate the combined fuel economy, in miles per kilogram and miles per gasoline gallon equivalent, by harmonically averaging the unrounded city and highway values, weighted 0.55 and 0.45 respectively. Round miles per kilogram to the nearest whole number and round miles per gasoline gallon equivalent to the nearest whole number.

(2) For the purposes of calculating the combined CO₂ emissions value for a model type, to be used in displaying on the label under subpart D of this part, the manufacturer shall:

(i) For gasoline-fueled, diesel-fueled, alcohol-fueled, and natural gas-fueled automobiles, and for dual fuel automobiles that can operate on gasoline or diesel fuel, arithmetically average the unrounded city and highway values, determined in paragraphs (a)(1) or (2) of this section and (b)(1) or (2) of this section, weighted 0.55 and 0.45 respectively, and round to the nearest whole gram per mile; or

(ii) For alcohol dual fuel and natural gas dual fuel automobiles operated on the alternate fuel, arithmetically average the unrounded city and highway CO₂ emission values from the tests performed using the alternative fuel as determined in paragraphs (a)(3) and (b)(3) of this section, weighted 0.55 and 0.45 respectively, and round to the nearest whole gram per mile.

(iii) CO₂ label information is based on tailpipe emissions only, so CO₂ emissions from electric vehicles and fuel cell vehicles are assumed to be zero.

(iv) For plug-in hybrid electric vehicles, calculate combined CO₂ emissions as follows:

(A) Determine city and highway CO₂ emission rates for vehicle operation after the battery has been fully discharged (“gas only operation” or “charge-sustaining mode”) as described in paragraphs (a) and (b) of this section.

(B) Determine city and highway CO₂ emission rates for vehicle operation starting with a full battery charge (“all-electric operation” or “gas plus electric operation”, as appropriate, or “charge-depleting mode”) as described in §600.116. Note that CO₂ label information is based on tailpipe emissions only, so CO₂ emissions from electricity are assumed to be zero.

(C) Calculate a composite city CO₂ emission rate and a composite highway CO₂ emission rate by combining the separate results for battery and engine operation using the procedures described in §600.116. Use these values to calculate the vehicle's combined CO₂ emissions as described in paragraph (c)(2)(i) of this section.

(d) Calculating combined fuel economy, CO₂emissions, and driving range. (1) If the criteria in §600.115-11(a) are met for a model type, both the city and highway fuel economy and CO ₂ emissions values must be determined using the vehicle-specific 5-cycle method. If the criteria in §600.115-11(b) are met for a model type, the city fuel economy and CO ₂ emissions values may be determined using either method, but the highway fuel economy and CO ₂ emissions values must be determined using the vehicle-specific 5-cycle method (or modified 5-cycle method as allowed under §600.114-12(b)(2)).

(2) If the criteria in §600.115 are not met for a model type, the city and highway fuel economy and CO ₂ emission label values must be determined by using the same method, either the derived 5-cycle or vehicle-specific 5-cycle.

(3) Manufacturers may use one of the following methods to determine 5-cycle values for fuel economy, CO ₂ emissions, and driving range for electric vehicles:

(i) Generate 5-cycle data as described in paragraph (a)(1) of this section using the procedures of SAE J1634 (incorporated by reference in §600.011) with amendments and revisions as described in §600.116-12(a).

(ii) Multiply 2-cycle fuel economy values and driving range by 0.7 and divide 2-cycle CO ₂ emission values by 0.7.

(iii) Manufacturers may ask the Administrator to approve adjustment factors for deriving 5-cycle fuel economy results from 2-cycle test data based on operating data from their in-use vehicles. Such data should be collected from multiple vehicles with different drivers over a range of representative driving routes and conditions. The Administrator may approve such an adjustment factor for any of the manufacturer's vehicle models that are properly represented by the collected data.

(e) Fuel economy values and other information for advanced technology vehicles. (1) The Administrator may prescribe an alternative method of determining the city and highway model type fuel economy and CO₂ emission values for general, unique or specific fuel economy labels other than those set forth in this subpart C for advanced technology vehicles including, but not limited to fuel cell vehicles, hybrid electric vehicles using hydraulic energy storage, and vehicles equipped with hydrogen internal combustion engines.

(2) For advanced technology vehicles, the Administrator may prescribe special methods for determining information other than fuel economy that is required to be displayed on fuel economy labels as specified in §600.302-12(e).

(f) Sample calculations. An example of the calculation required in this subpart is in Appendix III of this part.

[76 FR 39554, July 6, 2011, as amended at 76 FR 57380, Sept. 15, 2011; 77 FR 63183, Oct. 15, 2012; 81 FR 74002, Oct. 25, 2016; 88 FR 4483, Jan. 24, 2023; 89 FR 28209, Apr. 18, 2024]