The average fuel efficiency of light-duty cars, trucks, and SUVs reached 24.9 miles per gallon for the 2017 model year, which is a record high, even as the industry may have trouble meeting future standards, the U.S. Environmental Protection Agency said in a new report.

The findings came in the EPA's annual Automotive Trends Report, which credited manufacturers for continuing to increase fuel economy and reduce pollution through innovative engineering choices. However, there are "legitimate concerns" about their ability to meet rising annual requirements that were put in place during Obama's administration. President Trump began an effort to roll back those standards with the Safe Affordable Fuel Efficient Vehicles rule, which he introduced in August 2018.

"EPA and DOT will have those concerns in mind as we move forward with our Safe Affordable Fuel Efficient Vehicles rule, which would allow the industry to meet aggressive yet attainable standards, reduce the price of new vehicles, and help more Americans purchase cleaner, safer, and more efficient vehicles," said Andrew Wheeler, EPA administrator.

The 2017-MY fuel economy was slightly higher than the 2016 model year. Since the 2004 model year, fuel economy has improved in 11 out of 13 years.

Vehicles also had a record low amount of greenhouse gas emissions, especially as sport utility vehicles reached a record level of market penetration. The average real-world carbon-dioxide emission rate for all new vehicles fell by 3 grams per mile to 357 grams per mile, which is the lowest level on record.