Vehicle inspection in the United States
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.
The Clean Air Act of 1990 required some states to enact vehicle emissions inspection programs.
States impacted were those in metropolitan areas where air quality did not meet federal standards.
[1] Some states, including Kentucky and Minnesota, have discontinued their testing programs in recent years with approval from the federal government.
[citation needed] Bexar County (San Antonio) emissions testing beginning on November 1, 2026 Car Inspection Requirements By State
Periodic safety inspection required
VIN inspection required upon sale or transfer
Safety inspection required when registering a vehicle from another jurisdiction
Emissions testing required in some areas
Emissions testing required in all areas
No inspection required
Striped: Both safety and emissions testing required
