The Trump administration could try to dramatically weaken the vehicle fuel economy standards adopted during the final days of the Obama administration.
One of the options being considered by the National Highway Traffic Safety Administration would reduce the average fuel economy standard for 2025 from 46 miles per gallon to 36 miles per gallon.
The agency says that would mean only about 10% of new cars and light trucks would have to be hybrid or plug-in electric, compared to 61% under the previous standard.
Automakers have been pushing hard for a reduction in the standard. They say Americans are buying larger vehicles because of low gas prices and the standard will be too difficult to meet.
But they also want one national standard, and it seems unlikely California, which has a federal waiver to set its own standards, would agree to the new proposal.
The waiver is included as part of the Clean Air Act, so a move by the Trump administration to revoke the waiver would set up a fight in the courts.