DEEP: Vehicle Emission Testing

Vehicle Emissions



Connecticut's Inspection & Maintenance (I/M) Program:

Connecticut's Inspection and Maintenance (I/M) Program is an important part of the strategy to ensure that Connecticut is positioned to attain the National Ambient Air Quality Standard for Ozone  and provides a corollary benefit in particulate matter reduction.  Connecticut's I/M Program, dating back to 1983, has a long history of effectively minimizing vehicle emissions and results in more emission reductions than any other state implemented air pollution control strategy.  

Initially operated as a centralized I/M program from 1983 to 2002, Connecticut amended its statutory authority to develop and implement a decentralized I/M program, which commenced in October of 2003.  This change improved convenience for the public by vastly increasing the number of test stations, decreasing the waiting time for emissions testing, directly connecting emissions testing with the repair industry, and enhancing opportunities for small business development. {Green-Car}

Connecticut's Ozone Attainment Plan includes control programs expected to reduce ozone-causing pollutants.  The I/M program accounts for approximately 10% of these reductions.  These emission reductions are an integral part of our air quality attainment efforts and are important as part of a balanced strategy that includes reductions from stationary, area, and mobile source sectors.

{CT Emissions Logo} Connecticut's Emissions Program  (Link to DMV) - search for your test date, test center, and find answers to your emissions testing questions.


Periodic I/M Reports:
DEEP and the Department of Motor Vehicles coordinate to evaluate and provide periodic reports on the I/M program in accordance with U.S. Environmental Protection Agency requirements.

On-Board Diagnostic (OBD) Testing Systems:

PA 09-187, Section 55 directed CT DEEP to develop the following report, which was issued on December 11, 2009: "Evaluation of the Exclusive Utilization of On-board Diagnostic Testing for Connecticut's Motor Vehicle Inspection and Maintenance" (PDF), Report Appendices A,B,C,D (4.8mb PDF)

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Content last updated on August 26, 2019