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 This website is no longer updated and links to external websites and some internal pages may not work.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 »

Vehicle and Engine Certification

Compliance Activity Reports for Vehicles and Engines

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

EPA oversees a broad set of compliance activities to ensure that vehicle and engine manufacturers satisfy their regulatory obligations. These activities include issuing certificates of conformity before vehicles and engines enter commerce, monitoring and testing vehicles and engines that have been sold and are “in-use,” auditing manufacturers and their testing facilities, and monitoring required reporting.

EPA periodically issues progress reports on vehicle and engine compliance activities. The latest report covering the 2014-2017 model years was issued in April of 2019 and updates and builds upon the data and information presented in the first four reports, which cover compliance activities for the 2007 – 2013 model years.