Troubles with California's Smog Check

1. Failure of the Smog Check Programme Reducing emissions of pollutants from cars requires that new vehicles be designed and built to pollute less, and also requires some ongoing inspection and maintenance programme to ensure that a vehicle's operation conforms to those design standards. This paper focuses on these programmes, commonly called Smog Check programmes. The most extensive and well-studied Smog Check programme in the United States is in California. Though that state is not typical in all respects, examining its experience is instructive. California implemented its first wide-ranging Smog Check programme in 1984. The programme required gasoline-powered passenger cars and light trucks to pass inspection every two years. Inspections were performed at private garages licensed by the state. Garages measured hydrocarbon (HC) and carbon monoxide (CO) emissions and in spected some emission control devices. The US Environmental Protection Agency had estimated that such a programme could reduce emissions of HC and CO by 25 per cent (Sommervilleei a/., 1993, p.33). The actual results were disappointing: in 1987 reviewers reported that the programme reduced HC emissions by only 12.3 per cent, and reduced CO emissions by only 9.8 per cent. The programme's effectiveness was, at best, half that predicted. The failure led to changes in 1990, including the use of new equipment designed to reduce the opportunity for faking test results. The report that recommended the changes predicted emission reductions of 28 per cent for HC, 27 per cent for CO, and 12 per cent