Clean Truck Check (HD I/M) & Periodic Smoke Inspection Programs
CARB’s diesel engine regulations and programs cover a wide range of equipment operating in California and are designed to reduce air pollution caused by diesel-powered and other non-gas fossil-fuel powered equipment. Mobile sources including cars, trucks, ships, and off-road equipment continue to contribute a majority of smog-forming NOx and the largest portion of GHG emissions in California. They are also a significant source of toxic air contaminants such as diesel particulate matter (PM) and formaldehyde that directly impact community health. Enforcement of these regulations helps move California closer to our clean-air goals, promotes a level-playing field for compliant businesses and individuals, and supports the health of communities, especially disadvantaged communities most impacted by pollution.
More about this program
Notice to Submit to Testing (NST) Letter
Responding to a Notice to Submit to Testing letter issued by CARB Enforcement under HD I/M.