A lobbying group for 10 major automakers said Tuesday the government is underestimating the cost of increasing fuel economy standards and wants those standards to go into effect too quickly.
In a 77-page response to a request for comments on the government's proposed new rules, the Alliance of Automobile Manufacturers said the National Highway Traffic Safety Administration's goal of increasing fuel economy by 4.5 percent per year between 2011 and 2015 "goes beyond what is technologically feasible and economically practicable."
"It would require manufacturers to expend resources at a pace that is excessive given the fact that the auto industry is already under economic stress," the alliance said.
NHTSA is aiming to implement a law passed last year by Congress that requires new cars and trucks to meet a collective fuel economy average of 35 miles per gallon by 2020. That law was supported by automakers.
NHTSA's proposal, released in April, would require new cars and trucks to meet a fleet average of 31.6 mpg by 2015.
The automaker alliance said NHTSA also is underestimating the costs of improving technology.
NHTSA estimates that its proposed rules would add $821 to the cost of new vehicles in 2015, but the alliance said its estimate is $2,063, in part because NHTSA underestimates the cost of the raw materials that go into hybrid batteries and other fuel-saving technologies. The alliance said the rules would end up costing consumers more than they could save on fuel, and could reduce overall U.S. sales.
NHTSA spokesman Rae Tyson said the agency would not discuss the comments Tuesday.
The alliance represents General Motors Corp., Ford Motor Co., Chrysler LLC, Toyota Motor Corp., BMW AG, Mazda Motor Corp., Mercedes-Benz USA, Mitsubishi Motors, Porsche AG and Volkswagen AG.
Tuesday was the deadline to submit comments to NHTSA on the fuel economy proposal. The agency had received more than 100 comments as of Tuesday morning.