The Department of Transportation said it would put off a final rule on Corporate Fuel Economy Standards, in a process begun last year.

"The recent financial difficulties of the automobile industry will require the next administration to conduct a thorough review of matters affecting the industry," the department said in a statement.

The statement said the agency "has done significant work that will position the next transportation secretary to finalize a rule before the April 1, 2009 deadline."

The new administration of president-elect Barack Obama takes over on January 20. Obama has selected Republican representative Ray LaHood to head the agency.

Last year, the agency proposed improved fuel efficiency for both passenger vehicles and light trucks by 4.5 percent per year over the five-year period ending in 2015 in an effort to save fuel and reduce emissions.

A bill signed in 2007 by President George W. Bush requires improved standards by 2020.