The average fuel economy of new U.S. trucks, cars, SUVs and vans sold in September fell 0.3 mpg from August, to 24.6 mpg, according to a monthly report from the University of Michigan Transportation Research Institute.
The decline is “reflecting the recent reduction in the price of gasoline,” making fuel economy a lower priority among new-vehicle buyers, researcher Michael Sivak wrote in an e-mail.
The average fuel economy of 2013 model new vehicles sold in the United States from October 2012 through September 2013, was 24.7 mpg, up 1.2 mpg from 2012 model new vehicles, said the report from researchers Sivak and Brandon Schoettle.
Despite the drop in September, average fuel economy of new light vehicles sold in the United States is up 4.5 mpg since the researchers began collecting data in October 2007.
Average sales-weighted fuel economy was calculated from the monthly sales of individual models and the combined city-highway fuel economy ratings from the EPA Fuel Economy Guide for each model.
The institute's national Eco-Driving Index, which calculates the average monthly greenhouse gas emissions from a U.S. driver who bought a new vehicle during the month, held steady at 0.80 for the third consecutive month in July. A lower index score is better, and the scores are compared with a base score of 1 in October 2007, when the researchers began collecting data.
"This value indicates an improvement of 20 percent since October 2007," Sivak wrote. "The EDI takes into account both the fuel used per distance driven and the amount of driving."