The Biden administration sets a fuel economy standard of 50 miles per gallon for 2031

The final version of the standards is weaker than the agency's initial proposal, which automakers said would be impossible to meet.

The fuel economy standards published Friday are designed to complement emissions rules set by the EPA in March, and take into account efforts led by California regulators to stimulate electric vehicle adoption. Private cars and trucks are a major source of carbon emissions, and a key part of the Biden administration's environmental agenda includes pushing for a significant increase in the number of battery-powered vehicles on the road.

Automakers can comply with the new standards by improving the fuel efficiency of their gas-burning vehicles, and by increasing the number of electric-powered models they produce.

“Not only will these new standards save Americans money at the stations every time the stations are full, they will also reduce harmful pollution and make America less dependent on foreign oil,” Transportation Secretary Pete Buttigieg said in a statement.

Environmentalists have had mixed reactions to the new rules, with some saying they go no further and others hailing them as an important step forward.

“Today’s final rule is another important step toward reducing carbon pollution and curbing climate change,” said Harold Weimer, president and CEO of the American Lung Association. “New fuel efficiency requirements for new cars, SUVs and pickup trucks are good for consumers and for health. More efficient vehicles will save lives and money.

In addition to challenging the stringency of the proposals, the auto industry has raised concerns that by following different sets of overlapping rules, the administration risks creating legal risks for automakers. But officials said the various agencies have worked to collaborate on standards. John Bozzella, CEO of the Alliance for Automotive Innovation, said the National Highway Traffic Safety Administration appears to have issued “a rule that works with other federal rules related to automobile exhaust.”

The Biden administration has taken several steps to attract more drivers to electric vehicles, supporting tax credits for purchases and investing in a network of public chargers. But sales growth has slowed in recent months, as the size of the electric fleet outpaces the number of places to be connected.

This campaign also faced opposition from Republicans. Donald Trump, the party's presumptive presidential nominee, said he would abandon Biden's climate rules.