This joint resolution nullifies the Environmental Protection Agency (EPA) rule titled Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles—Phase 3 and published on April 22, 2024. Heavy-duty vehicles generally include vocational vehicles (such as public utility trucks and school buses) and tractors (such as cabs on tractor-trailer trucks).

Among other requirements, the rule phases in standards to reduce greenhouse gas emissions from certain heavy-duty vehicles. The phased-in standards replace previous standards that were established under the EPA's Greenhouse Gas Emissions and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles—Phase 2 rule with more stringent standards.