The eventual 49 miles-per-gallon standard is based on lab testing. The Environmental Protection Agency, which shares responsibility for overseeing the standards and issued its own companion rule in December, estimates the tougher mileage rules would achieve roughly 40 miles per gallon in real -world conditions, up from about 32 miles per gallon under the Trump administration.
With gas prices soaring, oil markets beset by events in Ukraine, and Biden’s climate agency stalled in Congress, administration officials have emphasized the savings Americans will see at the pump in the coming years because of Friday’s rule. Americans buying new vehicles purchased through 2030 will spend about $192 billion less on gas because of the rule, according to the administration.
Mileage standards are an important tool for cutting greenhouse gases, with the transportation sector the biggest source of such emissions in the United States. On Friday, Transportation Secretary Pete Buttigieg called the rule “a big step, and just one part” of a broader strategy to climate address change by shifting toward cleaner energy and electric vehicles.
Whether the United States can dramatically reduce its on-road emissions will depend, in large part, on how widely electric vehicles are adopted.
Buttigieg on Friday called on Congress to pass a stalled measure that would provide tax credits to buyers of electric vehicles. That would drop the price of an electric pickup “from about 40,000 bucks down into the 20s. We could do that through policy that is available right now,” he said.
Some environmental advocates said the administration needed to go further to meet its climate goals, but oil-producing states, led by Texas, are seeking to overturn the EPA’s December rule.
The NHTSA rule will be accompanied by voluminous backup documentation, including cost-benefit and environmental-impact analyses that show the complexities of reducing emissions from gas-powered vehicles even as the auto industry pledges to sharply increase its sales of electric vehicles.
The 49 mile-per-gallon average required under NHTSA’s rule is slightly higher than what the agency proposed in August. That figure is based on laboratory testing and overstates performance in the real world, according to the EPA.
The two agency rules are largely in line with each other, although they are not identical.
EPA estimates for real-world results from emissions standards take into account colder temperatures, faster driving, and the use of air conditioning, which decrease mileage efficiency compared to what NHTSA officials calculate based on lab results.
Dan Becker, director of the Safe Climate Transport Campaign at the Center for Biological Diversity, said NHTSA’s rule fell short of what is needed in the way mileage standards are governed in the United States.
“The stringency level isn’t up to what the climate challenge presents, and there are too many loopholes that allow auto companies to make too many gas-guzzlers,” Becker said. He said mileage standards for SUVs, pickups, and vans are weaker than those for cars, which has contributed to automakers’ shift away from producing smaller passenger cars.
The mileage standards largely echo those established in an agreement between California, Ford, and several foreign carmakers in 2019 as the Trump administration sought to roll back Obama-era standards and revoke California’s longstanding ability to set stricter pollution limits.
Ford on Friday noted its history of standing with California on mileage standards during the Trump years. In a statement, chief policy officer and general counsel Steven Croley said the company “applauds NHTSA’s efforts to strengthen fuel economy standards and create consistent benchmarks to accelerate our national transition toward a zero-emissions transportation future.”