Banners promoting General Motor trucks and SUV's are displayed at Community Chevrolet in Burbank, California June 3, 2008. General Motors Corp on Tuesday said it was closing four truck plants and could sell its Hummer brand to cut slow-selling trucks and SUVs from its lineup in response to higher gasoline prices the automaker now sees as a permanent threat to its business. REUTERS/Fred Prouser (UNITED STATES)