Vehicle Emissions Inspection and Maintenance (I/M): Regulations

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Vehicle inspection and maintenance (I/M) programs help improve air quality by identifying cars and truck with high emissions and that may need repairs. Owners or operators of vehicles with high emissions are notified to make any repairs so that emissions are within legal limits. The 1990 Amendments to the Clean Air Act (CAA) made I/M mandatory for several areas across the country. This page contains regulations promulgated by EPA to facilitate the states implementation of this CAA mandate.

Amendments to Vehicle Inspection Maintenance Program Requirements to Address the 8-Hour National Ambient Air Quality Standard for Ozone

Fact Sheet (PDF) (3 pp, 27 K, EPA420-F-04-059, December 2004)
Proposed Rule (PDF) (11 pp, 212 K, published January 6, 2005)
Fact Sheet (PDF) (2 pp, 149 K, EPA420-F-06-028, March 2006)
Final Rule (PDF) (8 pp, 178 K, published April 7, 2006)
Press release: To Help Meet More Protective Ozone Standard, EPA Will Update Vehicle Inspection and Maintenance Program Requirements (December 22, 2004)

Amendments to Vehicle Inspection Maintenance Program Requirements Incorporating the On-Board Diagnostic Check

Proposed Rule (PDF) (13 pp, 294 K, published September 20, 2000)
Final Rule (PDF) (24 pp, 267 K, published April 5, 2001)

Additional Flexibility Amendments to Vehicle Inspection Maintenance Program Requirements.

Fact Sheet (PDF) (3 pp, 12 K, EPA420-F-99-030, August 1999)
Proposed Rule (PDF) (10 pp, 251 K, published August 20, 1999)
Final Rule (PDF) (10 pp, 297 K, published July 24, 2000)

I/M Program Requirement - On-Board Diagnostic Checks Amendment to the Final Rule

Proposed Rule Fact Sheet (PDF) (3 pp, 11 K, EPA420-F-98-002, January 1998)
Proposed Rule (PDF) (3 pp, 116 K, published December 22, 1997)
Final Rule Fact Sheet (PDF) (3 pp, 13 K, EPA420-F-98-017, April 1998)
Final Rule (PDF) (6 pp, 172 K, published May 4, 1998)

Minor Amendments to Inspection Maintenance Program Evaluation Requirements; Amendment to the Final Rule

Fact Sheet (PDF) (3 pp, 10 K, EPA420-F-97-052, August 1997)
Proposed Rule (PDF) (5 pp, 128 K, published September 19, 1997)
Final Rule (PDF) (7 pp, 177 K, published January 9, 1998)

I/M Program Requirements Minor Amendments

Direct Final Rule (PDF) (3 pp, 117 K, published September 23, 1996)

I/M Requirement for On-Board Diagnostic Checks

Proposed Rule (PDF) (8 pp, 186 K, published August 18, 1995)
Final Rule (PDF) (9 pp, 155 K, published August 6, 1996)
Correction of Final Rule (PDF) (1 pg, 93 K, published August 27, 1996) On page 40946, first column, Sec. 51.372(b)(3), the last line, "August 6, 1996" should read "August 6, 1998".

Inspection/Maintenance Ozone Transport Region (OTR) Flexibility Amendments.