An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Regulations for Emissions from Vehicles and Engines

Final Rule for Control of Emissions of Air Pollution From New Motor Vehicles: In-Use Testing for Heavy-Duty Diesel Engines and Vehicles

On this page:

Rule Summary

The U.S. Environmental Protection Agency (EPA) is establishing a manufacturer-run, in-use emissions testing program for heavy-duty diesel trucks. Under this program, manufacturers will measure gaseous and particulate exhaust emissions from diesel engines using portable onboard emission measurement systems. This cooperative effort represents a significant advance in helping to ensure that the benefits of more stringent emission standards are realized under real-world driving conditions.

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.

Rule History

Additional Resources

Fact Sheet

Regulations for Emissions from Vehicles and Engines Home