For the second straight
month, fuel economy of all new vehicles sold in the United States fell by 0.2
mpg—likely reflecting a slight drop in gas prices, say researchers at the
University of Michigan Transportation Research Institute (UMTRI).

Average fuel economy
(window-sticker values) of cars, light trucks, minivans, and SUVs purchased in
May was 23.7 mpg—down from 23.9 in April and 24.1 in March—but still the
fourth-best month on record and up 3.6 mpg (18%) 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 that are published with a two-month lag.

During March, the EDI stood
at 0.83, worse than the 0.81 mark in February, but the same as in January (the
lower the value, the better). The index currently shows that emissions of
greenhouse gases per driver of newly purchased vehicles are down 17%, overall,
since October 2007.

Finally, 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
values.

For May, unadjusted CAFE
performance was 29.1 mpg, down from 29.3 in April and 29.6 mpg in March, but an
increase of 18% (4.4 mpg) since October 2007.

Source: University of Michigan