The EPA has locked in regulations that establish stringent new fuel economy standards for cars and light trucks amid speculation that President-elect Trump plans to roll them back once he takes office. The Corporate Average Fuel Economy (CAFE) and greenhouse gas emissions standards were issued jointly by the EPA and the Department of Transportation in 2012. The emission standards take effect with the 2017 model year.

The phased-in fuel economy standard starts with a rise to an average 35 mpg for the 2017 models and increases to 36 mpg in 2018. The standard then increases to more than 37 mpg in 2019. By 2021, automakers will be required to hit a combined average of 41 mpg for cars and trucks. If the rules for model years are left in place, the emission standard will increase to about 43 mpg combined for cars and trucks in 2022, and finally to 54.5 mpg for cars and 40 mpg for trucks in 2025.

The 2012 rulemaking required the EPA to review the technical feasibility and cost of achieving the 54.5 and 40 mpg standards in 2018 and make adjustments if automakers were having difficulty attaining the incremental increases. Instead, the EPA completed the review last week, more than a year earlier than expected, and determined that automakers are able to meet the scheduled increases from both a technical and cost perspective. While there may be other regulatory or legislative avenues to roll back the standards, the EPA move removes the opportunity for an easy administrative fix by the Trump administration.