The average sales-weighted fuel economy of new vehicles sold continues to drop.
According to University of Michigan researchers Michael Sivak and Brandon Schoettle, the average fuel economy of new vehicles sold in the U.S. in September was 25.2 mpg, marking a 0.1-mpg decrease compared to August. The decline is likely due to the increased proportion of light trucks among the vehicles sold, said the researchers. Overall, average fuel economy is down 0.6 mpg from the peak reached in August 2014, but is still up 5.1 mpg from October 2007, when Sivak and Schoettle first started monitoring the data.
The sales-weighted fuel economy is calculated from the monthly sales of individual models of light-duty vehicles, which includes cars, SUVs, vans and pickup trucks, and the combined city/highway fuel economy ratings published in the EPA Fuel Economy Guide. For 2016, average fuel economy was highest in May when it reached 25.5 mpg. It has been declining since.