The average fuel economy of vehicles sold in August fell 0.1 mpg to 25.3 mpg from July, according to the University of Michigan's Transportation Research Institute (UMTRI).
The decline likely reflects lower gasoline prices and an increase in sales of light-duty trucks, according to UMTRI researchers Michael Sivak and Brandon Schoettle. Fuel economy is down 0.5 mpg from the peak reached in August of 2014, but still up 5.2 mpg since October 2007 when the institute began monitoring.
The University of Michigan Eco-Driving Index (EDI) — an index that estimates the average monthly emissions of greenhouse gases generated by an individual U.S. driver — was 0.83 in June, up 0.01 from the value for May (the lower the value, the better). This value indicates that the average new-vehicle driver produced 17% lower emissions in June than in October 2007, but 5% higher emissions than the record low reached in both August 2014 and August 2015.