U.S. auto fleet hits record high fuel efficiency in '17 U.S. auto fleet hits record high fuel efficiency in '17 March 6, 2019 dzadmin Comments 0 Comment The EPA said the average fuel efficiency of cars and trucks hit a new record high in the 2017 model year at 24.9 miles per gallon, but said there are “legitimate concerns” about the industry’s ability to meet rising annual requirements.