Overall U.S. vehicle fleet gas mileage rose only slightly over last 25 years

1991 BMW M5The average fuel economy of the new cars and light trucks sold in the U.S. is appreciably higher than it was 10 years ago. The University of Michigan Transportation Research Institute has demonstrated that in its regular reports calculating new-car average fuel economy since October 2007. But researchers Michael Sivak and Brandon Schoettle found...