CO2 reductions by the auto sector already approach the Paris goals for 2025.

Under the Paris Climate Accord, the Obama Administration agreed that by 2025 the U.S. would cut greenhouse emissions by 26-28% compared to 2005 levels. The auto sector has already made significant carbon reductions. Fleet-wide automobile CO2 reductions are already more than 21% lower than in 2005. And, this does not include carbon reductions made in our plants.
According to the 2017 EPA Trends Report, the real-world emissions of new cars and light trucks went from an average of 447 g/mi CO2 in 2005 to 352 g/mi in 2017 (preliminary).

More Facts on Auto CO2 Reductions