CAFE

The Corporate Average Fuel Economy (CAFE) standards are regulations in the United States, first enacted by the United States Congress in 1975,[1] after the 1973–74 Arab Oil Embargo, to improve the average fuel economy of cars and light trucks (trucks, vans and sport utility vehicles) produced for sale in the United States... The original CAFE standards sought to drive automotive innovation to curtail fuel consumption, and now the aim is to create domestic jobs and cut global warming.[3][4] Stringent CAFE standards together with government incentives for fuel efficient vehicles in the United States should accelerate the demand for electric vehicles. https://en.wikipedia.org/wiki/Corporate_average_fuel_economy

In early August 2018, the EPA and Department of Transportation, then operating under the Presidency of Donald Trump, issued a proposed ruling that, if enacted, would rollback some of the goals set in 2012 under President Obama. It proposed freezing the fuel economy goals to the 2021 target of 37 mpg, would halt requirements on the production of hybrid and electric cars, and would eliminate the legal waiver that allows states like California to set more stringent standards... New CAFE targets went into effect in June 2020 beginning with the 2021 model year, increasing at a rate of 1.5 percent per year, far lower than the nearly 5 percent increase they replace. Additionally, the minimum standard for domestic passenger cars was lowered from the 2020 model year level until the 2023 MY.

CAFE Standards set average Fuel Economy for US AutoMobile-s. The standards are

• 2020: 42.4 mgp for cars, 31.0 light trucks (SUVs)
• 2010: 27.5 mpg for cars (which hasn't changed since 1986), and 20.7 for light trucks (including SUV-s).

http://www.ita.doc.gov/td/auto/cafe.html

http://www.policyalmanac.org/environment/archive/crs_cafe_standards.shtml