On March 29, 2024, the U.S. Environmental Protection Agency (EPA) announced a final rule, “Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles – Phase 3” 

The latest Phase 3 rule sets new carbon dioxide (CO2) emission standards for heavy-duty vehicles through model year 2032 “with more stringent CO2 standards phasing in as early as MY 2027 for certain vehicle categories.”

The latest Phase 3 rule continues to address heavy-duty vehicles which the EPA separates into five categories: light heavy-duty vocational; medium heavy-duty vocational; heavy heavy-duty vocational; short-haul (day cab) tractors; and long-haul (sleeper cab) tractors.

The standards are technology-neutral and performance-based, allowing each manufacturer to choose what set of emissions control technologies is best suited to meet the standards and the needs of their customers.

For heavy-duty vocational vehicles such as delivery trucks, refuse haulers, and public utility trucks, the Phase 3 standards vary according to vehicle type and range up to 60% stronger than the previous Phase 2 standards for MY 2032. For tractors such as day cabs and sleeper cabs on tractor-trailer trucks, the Phase 3 standards vary according to vehicle type and range up to 40% stronger than the previous Phase 2 standards for MY 2032.