The US Environmental Protection Agency (EPA) is challenging the greenhouse gas and energy efficiency standards for passenger cars and light trucks (collectively, light-duty vehicles) for model years 2022-2025 adopted under the Obama administration.
The former standards, called the CAFE -Corporate Average Fuel Economy, introduced by the Obama administration, provided for gradual increases in vehicle autonomy to reach a goal of 54.5 miles per gallon of gas in 2025.
The new rules, jointly proposed by the EPA and the National Highway Traffic Safety Administration (NHTSA), limit the target to 37 miles per gallon after 2021.
This ruling would halt requirements on the production of hybrid and electric cars.

Following its Midterm Evaluation (MTE) for greenhouse gas emissions dating April 2018, the EPA has taken a new step in its process of relaxing environmental standards, including reconsidering the Clean Air Act (CAA) waiver granted to California. Indeed, under the Obama administration, California had an exemption allowing it to impose stricter standards for vehicle emissions of certain pollutants than federal requirements. More and more states are following California, and 12 states accounting for more than 40 percent of the market are forcing automakers to do better than EPA’s standards. To the extent that designing specific vehicles would be a problem for builders, it is de facto, the California standard becomes the federal standard.
On August 2, 2018, the Trump administration (EPA and DoT) issued a proposed ruling that, if enacted, would rollback some of the goals set in 2012 under President Obama.
The Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule would amend existing Corporate Average Fuel Economy (CAFE) and tailpipe carbon dioxide emissions standards for passenger cars and light trucks and establish new standards covering model years 2021 through 2026.
It would also abolish the legal waiver that allows states like California to impose stricter standards, which could lead to a long legal and political battle with California.

This decision is part of Donald Trump's intention to dismantle to a considerable extent the « Climate Plan » established by his predecessor Barack Obama, as the United States withdraws from the Paris Climate Agreement that is considered harmful to the US economic interests.
This decision already has international consequences, especially on the free trade agreement between the United States and South Korea which is being renegotiated for possible amendments, the new treaty should to be ratified before the beginning of the year 2019. One of the important topics of this agreement known as « Korus », signed in 2007 and entered into force in 2012, is the automobile market which constitutes a large part of the trade between the two countries - Korea South exporting many vehicles to the United States.

The EPA guidelines under the Trump administration go against the international movement to promote carbon-free transport, and do not allow a stimulation of American investments towards « cleaner » vehicles, which will have, besides the consequences on the fight against climate change and on human health because of air pollution, an impact on the US car industry in the long run.

Following official publication in the Federal Register, NHTSA and EPA hold a comment hearing period for 60 days on this proposal.