In a letter to Congress yesterday, the leaders of the big three U.S. automakers pledged to double production of flexible-fuel vehicles by 2010. They hope with this commitment to provide incentive to fuel providers to produce ethanol and other biofuels and install pumps to distribute them. They’ve produced 5 million flexible-fuel vehicles so far, which can run on gasoline or fuel blends of up to 85 percent ethanol. They project an additional 1 million vehicles this year and 2 million annually by 2010. (AP)