Bush obstructed efforts to increase fuel efficiency

In December 2007, the day after Bush signed Democratic legislation which modestly increases fuel efficiency standards, the administration blocked laws enacted in 18 states that would improve auto efficiency rules for a majority of Americans.

Source
BRODER, JOHN M. and BARRINGER, FELICITY. E.P.A. Says 17 States Can’t Set Emission Rules. New York Times. [Online] December 20, 2007. [Cited: July 17, 2008.] http://www.nytimes.com/2007/12/20/washington/20epa.html?_r=2&oref=slogin%3C&oref=login