All new cars sold in the U.S. saw fuel economy down 0.2 mpg, for the second month, reflecting a slight decrease in gas prices.
According to researchers at the University of Michigan Transportation Research Institute, average fuel economy for the minivans, SUVs and light trucks sold in May was 23.7 mpg, down from 23.9 in April and 24.1 in March, but up 18% from 3.6 mpg in October 2007, the first month of monitoring by UMTRI researchers Michael Sivak and Brandon Schoettle.
Sivak and Schoettle also issued, besides the average fuel economy, the monthly update of their national Eco-Driving Index. This estimates the average level of emissions generated monthly by an U.S. driver. The Eco-Driving Index relies on both the distance driven and the vehicle fuel economy. EDI stood at 0.83 in March, the same as in January, but worse than 0.81 in February. Since October 2007 emissions of greenhouse gases per driver of newly purchased vehicles decreased by 17%.
The unadjusted Corporate Average Fuel Economy performance, which is based on a different set of EPA rating from the window-sticker values, issued values of 29.1 mpg in May, down from 29.3 in April and 29.6 mpg, but up 18% from October 2007.