Average fuel economy ratings for new light-duty vehicles sold in the US continued to drop in September according to the University of Michigan’s Transportation Research Institute (UMTRI).
The average dropped by 0.1 miles per gallon in September compared to August to sit at 25.2 mpg according to the research by Michael Sivak and Brandon Schoettle. That is down 0.6 mpg compared to the fuel economy peak hit in August 2014 of 25.8 mpg.
This marks the third straight month of declines in average fuel economy, likely caused by the low price of fuel that has sparked strong SUV and truck sales. Green car sales also fell by roughly four percent in September, partly because some of the U.S.’s best selling green cars have been or will be redesigned in the near future, including the Chevy Volt and Nissan Leaf.
Volkswagen’s diesel scandal may also have contributed, with the German automaker seeing a plunge in sales of its fuel efficient diesel models.