Mobile Sources - Auto Inspection and Maintenance (I/M) Programs

Control of pollutants from mobile sources

Figure: Current auto inspection and maintenance program

Under the 1990 Clean Air Act, auto manufacturers will build cleaner cars, and cars will use cleaner fuels. However, to get air pollution down and keep it down, a third program is needed; vehicle inspection and maintenance (I/M), which makes sure cars are being maintained adequately to keep pollution emissions (releases) low. The 1990 Clean Air Act includes very specific requirements for inspection and maintenance programs.

Auto inspection and maintenance programs are designed to make sure that the cars we buy and drive perform their best and live up to their pollution control promise. Auto inspection and maintenance programs require the testing of motor vehicles in parts of the country with unhealthy air and the repair of those that do not meet standards. I/M tests use special equipment to measure the pollution in car exhaust. These tests check that the car's key emission controls are installed as designed and then analyze the exhaust to check acceptable control of carbon monoxide and hydrocarbons. Advanced tests also check nitrogen oxide emissions.