The main purpose of this legislation is to amend the Clean Air Act in order to protect the sale of vehicles that use internal combustion engines. The bill aims to ensure that states cannot impose regulations that would limit or eliminate the availability of these types of vehicles in the market. Key provisions of the bill include changes to how state standards are applied under the Clean Air Act. Specifically, it prohibits states from creating standards that would restrict the sale or use of new motor vehicles with internal combustion engines.