The average fuel-economy rating for new vehicles sold in the United States in December 2017 was 25.0 miles per gallon, down from the revised November average of 25.2 mpg.
For all of 2017, the average fuel-economy rating for new vehicles sold was 25.2 mpg, unchanged compared with the 2016 average.
Compared with October 2007, fuel economy ratings on new cars sold has improved by 4.9 miles per gallon, or about 24%.
While the window sticker average is 4.9 mpg higher than when the data were first collected, the sales-weighted average is 0.5 mpg below its revised all-time high of 25.5 mpg set in August 2014 and the slightly below highest monthly average (25.4 mpg in July) for 2017.
The data are based on the average sales-weighted fuel-economy rating printed on a new car’s window sticker and is compiled by Michael Sivak and Brandon Schoettle of the University of Michigan’s Transportation Research Institute.
The sales-weighted unadjusted Corporate Average Fuel Economy (CAFE) performance rating averaged 31.1 miles per gallon in December, a decrease of 0.2 mpg month-over-month and an improvement of 6.4 mpg since October 2007. These values are not directly comparable to the window-sticker ratings because these are adjusted by the EPA and used to derive the window-sticker ratings.
Sales of pickup trucks from the Detroit Three automakers (GM, Ford, Fiat Chrysler) were strong again in December, totaling about 223,887 full-size pickups for the month. Because fuel economy is lower for light trucks, sport utility vehicles and crossovers — the most popular vehicles for U.S. buyers — the sales-weighted declines in fuel economy ratings are due in large part to higher sales of these vehicles.