ANN ARBOR—Gas mileage of new vehicles sold in the U.S. slipped last month, say researchers at the University of Michigan Transportation Research Institute.
The average fuel economy (window-sticker value) in August was 25.3 mpg—down 0.1 mpg from July but just 0.2 mpg less than the peak of 25.5 mpg three years ago.
Overall, fuel economy is up by 5.2 mpg since October 2007—the first full month of monitoring by Michael Sivak and Brandon Schoettle.
In addition to average fuel economy, Sivak and Schoettle issued a monthly update of their national Eco-Driving Index, which estimates the average monthly emissions generated by an individual U.S. driver. The EDI takes into account both the fuel used per distance driven and the amount of driving—the latter relying on data that are published with a two-month lag.
During June, the EDI worsened slightly to 0.83 (the lower the value, the better)—up from 0.82 the month before. The index currently shows emissions of greenhouse gases per driver of newly purchased vehicles are down 17 percent, overall, since October 2007—but 5 percentage points higher than the record low reached in November 2013.