California Air Resources Board

This class covers the Heavy Duty Inspection and Maintenance (HD I/M) program, effective as of 1/1/2023, which requires all non-gasoline heavy-duty vehicles with a gross vehicle weight rating (GVWR) more than 14,000 pounds to pass emissions compliance inspections to operate in California. The HD I/M program is analogous to California’s Smog Check program for light-duty passenger vehicles and requires periodic inspections to ensure emissions control systems are maintained and function properly.