Corporate Average Fuel Economy: How Automakers Rank
Each year, the EPA calculates corporate average fuel economy based on gas mileage estimates for each car in an automaker's lineup, and the number of those cars produced that year. The lineups split into three groups: domestic passenger cars, which includes cars built using mostly domestically sourced parts, from either an American or foreign nameplate; imported passenger cars, built mostly with parts from abroad; and light trucks, which includes everything from pickup trucks and minivans to crossover SUVs, no matter where their parts come from.
Gas mileage figures come from automakers and go to the National Highway Traffic Safety Administration and then to the EPA for verification, so it can take until well into the following year for final CAFE numbers to be published. Based on NHTSA's data, here's where automakers stood for 2013 (based on the most recent data available, released in April 2013):
|Domestic Passenger Cars|
All manufacturers encompass their respective brands as of 2013 — i.e., Toyota includes Lexus and Scion.
|Imported Passenger Cars|
|14.||Jaguar Land Rover||27.9|
No pre-model year report; All manufacturers encompass their respective brands as of early 2012 — i.e., Toyota includes Lexus and Scion.
|14.||Jaguar Land Rover||21.4|
No pre-model year report; All manufacturers encompass their respective brands as of 2013 — i.e., Toyota includes Lexus and Scion.
Although CAFE ratings might look like an outright average of the gas mileage for all the vehicles in a carmaker's lineup, it's not that straightforward. The numbers on the window sticker and the ones reported to the government are "entirely separate," a NHTSA spokesman said. City and highway mileage figures come from the EPA's lab tests, with adjustments to replicate real-world conditions. CAFE figures, meanwhile, are derived using different testing procedures and have various incentives built in.
Mileage figures are averaged across a range of engines and transmissions per vehicle, too, so a particularly high- or low-mileage trim level could skew the numbers for an entire car line. Heavy-duty models are exempt from the calculations.