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Regulations/Standards
On this page
- EPA Emission Standards for Heavy-Duty Vehicles
- Federal School Bus Regulations
- EPA Emission Standards for Nonroad Engines, Equipment and Vehicles
Other resources
You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.
EPA Emission Standards for Heavy-Duty Vehicles
- EPA is working aggressively to reduce pollution from new heavy-duty diesel trucks and buses, by requiring them to meet tougher and tougher emission standards in the future.
- In the ongoing effort to reduce diesel emissions, EPA has set stringent standards which have taken effect over the years and now significantly reduce diesel emissions by up to 95 percent.
- 2004 Heavy-duty standards (PDF, 4 pages, 16K) (EPA420-F-00-026, July 2000)
- 2007 Heavy-duty standards (PDF, 4 pages, 124K) (EPA420-F-00-057, December 2000)
- Because these standards only apply to newly manufactured diesel engines, and diesel engines are durable and long-lasting, it will take a long time for new vehicles to replace the heavy-duty trucks and buses currently on the road. Clean School Bus USA is designed to jump-start the process of upgrading the fleet so that today's generation of school children can reap the benefits of technologies that are available now to reduce emissions.
- Learn more about the history of EPA emission standards (PDF, 3 pages, 64K)(EPA400-F-92-014, August 1994)
- View a timeline of the milestones in emissions controls
Federal School Bus Regulations
Although EPA sets emissions standards for diesel and natural gas engines,
EPA does not regulate school bus safety or use. The National Highway
Traffic Safety Administration (NHTSA) promulgates federal regulation of school bus safety 
including the use of safety belts on school buses.
EPA Emission Standards for Nonroad Engines, Equipment and Vehicles
EPA also sets emission standards for a range of gasoline- and diesel- powered engines, equipment, and vehicles that typically are not used on roads, streets and highways. These vehicles include construction, farm, and mining equipment, lawn equipment, chainsaws, snowmobiles, all-terrain vehicles, personal water craft, marine vessels, aircraft, and locomotives. These emission control programs significantly reduce the impact that nonroad engines and equipment have on the nation's air quality.
- Nonroad Diesel Equipment information
- Emission Standards Reference Guide for Heavy-duty and Nonroad Engines(PDF, 16 pages, 145K) (EPA420-F-97-014, September 1997)This document provides a detailed listing of current and proposed Federal and California standards for model years 1990 and later.