From the story here:
Mr. Trump on Wednesday announced plans to re-examine the fuel mandates, taking a step back from Obama-era environmental regulations. ... The standard for passenger cars stayed at 27.5 mpg from 1990 until 2007. In 2009, the government set a fuel economy standard of 34.1 mpg for cars and light trucks by 2016. In 2012, it set a new target of 54.5 mpg by 2025. The number can change depending on the mix of vehicles customers buy. Right now, it stands at 51.4 mpg because people are buying more SUVs and trucks.