a three-month drop, fuel economy of all new vehicles sold in the United
States remained unchanged in July, according researchers at the University
of Michigan Transportation Research Institute.
July, unadjusted CAFE performance was 29 mpg, the same as in June and
an increase of 17 percent, or 4.3 miles per gallon, since October 2007.
fuel economy or window-sticker values of cars, light trucks, minivans and sport utility vehicle purchased last month was 23.6 mpg, a 17 percent increase or 3.5 miles per gallon
from October 2007, the first month of monitoring
by UMTRI researchers Michael Sivak and Brandon Schoettle.
In addition to average fuel
economy, Sivak and Schoettle issued their 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 vehicle fuel economy and distance
driven—the latter relying on data, the lower the value the better, that are published with a two-month
During May, the EDI stood
at 0.82, up from 0.81 in April. Overall, the
index currently shows that emissions of greenhouse gases per driver of
newly purchased vehicles are down 18 percent,
overall, since October 2007.
Sivak and Schoettle report the unadjusted Corporate Average Fuel
Economy performance. This index is based on a different set of EPA
ratings than window-sticker
Fuel economy calculations, along with a graph and table of current and recent mpg:
www.umich.edu/~umtriswt/EDI_sales-weighted-mpg.html. By Joseph Szczesny