Vehicle inspection in the United States

In the United States, vehicle safety inspection and emissions inspection are governed by each state individually. 17 states have a periodic (annual or biennial) safety inspection program, while Maryland and Alabama require a safety inspection on sale or transfer of vehicles which were previously registered in another state. New Jersey discontinued its passenger vehicle safety inspection program on August 1, 2010.

In 1977, the federal Clean Air Act was amended by Congress to require states to implement vehicle emissions inspection programs, known as I/M programs (for Inspection and Maintenance), in all major metropolitan areas whose air quality failed to meet certain federal standards. New York's program started in 1982, California's program ("Smog Check") started in 1984, and Illinois' program started in 1986. The Clean Air Act of 1990 required some states to enact vehicle emissions inspection programs. State impacted were those in metropolitan areas where air quality did not meet federal standards. Some states, including Kentucky and Minnesota, have discontinued their testing programs in recent years with approval from the federal government.

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