Operational Aspects of the California Smog Check Program

California's vehicle inspection and maintenance program (Smog Check) began operation in March 1984. The program has achieved an 11 percent reduction in tailpipe emissions in tested vehicles. Public and industry acceptance is high. This paper describes operational aspects of the program, including what equipment is used, how results are measured, how quality is assured, how the law is enforced, and what changes are being made to increase program benefits.