After meeting with lawmakers in May to encourage ethanol use, heads of General Motors Corp., Ford Motor Co. and DaimlerChrysler AG's Chrysler said in a letter to Congress they would double production of vehicles that run on ethanol and other renewable fuels by 2010, to at least 2 million annually, according to Bloomberg.com. In a bid to cut reliance on imported oil and meet U.S. fuel-economy standards, GM now plans to "build and sell more than 800,000" flex- fuel vehicles for the U.S. by 2010, up from about 400,000 currently. Ford's output will double to about 500,000 and Chrysler's production will exceed 500,000, according to Bloomberg.com. With more than 5 million flex-fuel autos currently in the U.S., GM projects that ethanol may account for 10 percent of automobile fuel within five years, compared with about 3 percent now. If all 2 million of the new GM, Ford and Chrysler models in 2010 run on E85, they would save more than 3.5 billion gallons of gasoline a year, the companies said.