§ 600.311-12 Determination of values for fuel economy labels.

(a) Fuel economy. Determine city and highway fuel economy values as described in § 600.210-12(a) and (b). Determine combined fuel economy values as described in § 600.210-12(c). Note that the label for plug-in hybrid electric vehicles requires separate values for combined fuel economy for vehicle operation before and after the vehicle's battery is fully discharged; we generally refer to these modes as “Blended Electric + Gas” (or “Electric Only”, as applicable) and “Gas only”.

(b) CO2emission rate. Determine the engine-related CO₂ emission rate as described in § 600.210-12(d).

(c) Fuel consumption rate. Calculate the fuel consumption rate as follows:

(1) For vehicles with engines that are not plug-in hybrid electric vehicles, calculate the fuel consumption rate in gallons per 100 miles (or gasoline gallon equivalent per 100 miles for fuels other than gasoline or diesel fuel) with the following formula, rounded to the first decimal place:

(2) For plug-in hybrid electric vehicles, calculate two separate fuel consumption rates as follows:

(i) Calculate the fuel consumption rate based on engine operation after the battery is fully discharged as described in paragraph (c)(1) of this section.

(ii) Calculate the fuel consumption rate during operation before the battery is fully discharged in kW-hours per 100 miles as described in SAE J1711 (incorporated by reference in § 600.011), as described in § 600.116.

(3) For electric vehicles, calculate the fuel consumption rate in kW-hours per 100 miles with the following formula, rounded to the nearest whole number:

Fuel Consumption Rate = 100/MPG

(4) For hydrogen fuel cell vehicles, calculate the fuel consumption rate in kilograms of hydrogen per 100 miles with the following formula, rounded to the nearest whole number:

Fuel Consumption Rate = 100/MPG

(d) Fuel economy and greenhouse gas ratings. Determine a vehicle's fuel economy and greenhouse gas ratings as follows:

(1) For gasoline-fueled vehicles that are not plug-in hybrid electric vehicles (including flexible fuel vehicles that operate on gasoline), establish a single rating based only on the vehicle's combined fuel economy from paragraph (a) of this section. For all other vehicles, establish a fuel economy rating based on the vehicle's combined fuel economy and establish a separate greenhouse gas rating based on combined CO₂ emission rates from paragraph (b) of this section.

(2) We will establish the fuel economy rating based on fuel consumption values specified in paragraph (c) of this section. We will establish the value dividing the 5 and 6 ratings based on the fuel consumption corresponding to the projected achieved Corporate Average Fuel Economy level for the applicable model year. This is intended to prevent below-average vehicles from getting an above-average fuel economy rating for the label. We will establish the remaining cutpoints based on a statistical evaluation of available information from the certification database for all model types. Specifically, the mean value plus two standard deviations will define the point between the 1 and 2 ratings. The mean value minus two standard deviations will define the point between the 9 and 10 ratings. The 1 rating will apply for any vehicle with higher fuel consumption rates than the 2 rating; similarly, the 10 rating will apply for any vehicle with lower fuel consumption rates than the 9 rating. We will calculate range values for the remaining intermediate ratings by dividing the range into equal intervals. We will convert the resulting range intervals to equivalent miles-per-gallon values. We will define the greenhouse gas ratings by converting the values from the fuel economy rating intervals to equivalent CO₂ emission rates using the conventional conversion factor for gasoline (8887 g CO₂ per gallon of consumed fuel).