The Obama administration and auto industry are divided over whether future advancements in battery technology can support a proposal to roughly double fuel economy to 56 miles on a gallon of gasoline by 2025. Government officials estimate the costs of meeting the mileage and emissions target would add between $770 and $3,500 to the cost of a new car. The Alliance of Automobile Manufacturers says research shows such big gains in fuel economy could raise vehicle prices by $6,000 or more. The White House agreed to re-evaluate the fuel economy target in 2020.