Increased production and sales of pickup trucks and SUVs is lowering the average fuel economy for new vehicles, which fell 0.2 mpg to 25.1 mpg in June, according to the University of Michigan's Transportation Research Institute (UMTRI).
The decline also reflects lower fuel prices, according to Michael Sivak and Brandon Schoettle, UMTRI researchers who compiled the report.
The value for June is 5 mpg higher than October of 2007, when UMTRI began the monitoring. It's 0.4 mpg lower than the peak of 25.5 mpg reached in August of 2014.
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 — improved to 0.84 in April 2017, down from 0.85 in March 2017 (the lower the value, the better).
The EDI indicates that the average new-vehicle driver produced 16% lower emissions in April than in October of 2007, but 6% higher emissions than the record low reached in November of 2013.