The average fuel economy of new cars and light trucks sold in the U.S. this August was 24.3mpg, down 0.1 mpg from July. Average fuel economy is up 5.2 mpg since October 2007, the first month researchers Michael Sivak and Brandon Schoettle monitored the market, but down 0.2 mpg from the peak of 25.5 mpg reached in August 2014. Year-over-year U.S. light-vehicle sales slid 1.8 percent in August, with car deliveries descending 9.5 percent. Across the light-truck segment, pickup and crossover sales rose last month, 3.7 percent and 4.8 percent. Total light-truck sales gained 2.9 percent. The rise in average fuel economy occurred alongside an uptick in the price of gasoline. The average price of a gallon of regular gasoline Wednesday was $2.661, up from $2.199 a year ago.