Small drop in fuel economy, but still near all-time high

Despite a slight dip in June, fuel economy of new vehicles sold in the U.S. exceeded 25 mpg for the fifth straight month, say researchers at the University of Michigan Transportation Research Institute.

Average fuel economy (window-sticker values) of cars, light trucks, vans and SUVs purchased last month was 25.5 mpg, down from a record-high 25.6 mpg in May. Vehicle fuel economy is now up 5.4 mpg from October 2007, the first full month of monitoring by UMTRI researchers 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.

The EDI stood at 0.80 (the lower the value, the better) during April, up from 0.78 in both February and March. The index currently shows emissions of greenhouse gases per driver of newly purchased vehicles are now down 20 percent, overall, since October 2007.