On April 12, 2023, the EPA and Biden Administration proposed new rules governing emissions from new vehicles manufactured in the United States between 2027 and 2032. The EPA bases its authority to enact the regulations on section 202(a) of the Clean Air Act. The Biden administration previously laid the groundwork for more stringent vehicle emissions standards by order titled, Executive Order on Strengthening American Leadership in Clean Cars and Trucks, signed on August 5, 2021. That Order set a non-binding target of making 50% of new passenger cars, SUVs, and light trucks net zero emissions vehicles by 2030. The proposed rule goes beyond that.

In December 2021, the EPA finalized rules regarding emissions standards for new light duty vehicles, passenger cars and light trucks sold in the years 2023-2026. That rule seeks to raise the market share of electric vehicles from 7% in 2023 to 17% in 2026. The rules proposed in April would build on the 2026 parameters, requiring a 56% increase in fuel efficiency fleetwide from 2027 through 2032. This would require the share of new cars with net zero emissions to increase to 60% by 2030 and 67% by 2032. The share of medium duty vehicles with net zero emissions would increase to 46%. And 35-57% of new sales of heavy-duty commercial vehicles would be net zero emission by 2032.  

The EPA held a virtual hearing regarding the rule governing heavy-duty commercial vehicles on May 2-3, 2023. The public comment period for the rule closed on June 16, 2023. The EPA held a virtual hearing on the rule to govern small and medium vehicles from May 9-11, 2023. The public comment period closed on July 5, 2023.

The EPA will now finalize the rules, incorporating public comments and other new information. Political actors on both sides have sought to change the rules. Many Democratic lawmakers and environmental groups argue that the proposed rule does not go far enough. Some suggest standards should be put in place that would have 69% of light duty vehicles net zero emissions vehicles by 2032. Many Republican lawmakers have argued the emissions standards are too strict.

American auto manufacturers have invested a great deal in incorporating net zero emissions technologies into their products in recent years. However, many car companies do not believe the requirements set by the proposed rules are feasible given supply chain woes, specifically problems in rare elements necessary for high-capacity batteries used in electric vehicles. The EPA has said it took supply problems into account when developing the rules.