FILE - This Dec. 12, 2018, file photo shows traffic on the Hollywood Freeway in Los Angeles. New vehicles sold in the U.S. will have to travel an average of at least 40 miles per gallon of gasoline in 2026 under new rules unveiled by the government. The National Highway Traffic Safety Administration said Friday its fuel economy requirements will undo a rollback enacted under President Donald Trump. (AP Photo/Damian Dovarganes, File)