Amends federal transportation law to direct the Secretary of Transportation by regulation to prescribe (corporate) average fuel economy (CAFE) standards for automobiles manufactured after 2008 that ensure that the CAFE achieved by automobiles manufactured after 2016 is at least 33 miles per gallon, and meets other specified criteria. Authorizes the Secretary to establish separate standards for different classes of automobiles according to size.
Requires the Secretary to establish a CAFE credit trading program to allow a manufacturer that exceeds fuel economy standards to sell credits to another manufacturer.