ANN ARBOR—Last week, University of Michigan researchers released a study that showed that since late 2007, average fuel economy of new vehicles purchased has increased by more than 5 percent?thanks in large part to unemployment and gas prices (full study and news release can be found at www.umtri.umich.edu/news.php?id=2348).

Now, in a companion report, Michael Sivak and Brandon Schoettle of the U-M Transportation Research Institute suggest that as a result of improved fuel economy (from 20.2 mpg in October 2007 to 21.3 in April 2009) and a decrease in distance driven by U.S. motorists (a 3 percent drop in April 2009 compared to October 2007), carbon dioxide emissions per driver from purchased new vehicles have declined.

Emissions were lower in each month from October 2007 to April 2009. The greatest reduction?12 percent?was achieved in July 2008. The reduction in April 2009 was 8 percent.

If interested, Sivak can be reached at (734) 936-1089 or (734) 764-4158 or sivak@umich.edu. For a copy of the report: http://deepblue.lib.umich.edu/bitstream/2027.42/63100/1/102303.pdf(.pdf)