The Past and Future Benefits of Automobile Inspection and Maintenance Programs

The historical and predicted benefits associated with existing and imminent inspection and maintenance programs are investigated. Air quality trends analyses involving three techniques: paired city comparisons, time series analyses, and population exposure modeling are presented which quantify the benefits of I/M programs on Carbon Monoxide (CO) air quality.

Except for the New Jersey program, the authors conclude that there is little air quality related evidence to support the contention that I/M programs are contributing to improving air quality CO levels. In addition, future ambient trend data are even more unlikely to show any significant CO reduction trends due to I/M programs currently being implemented.