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Under the Clean Air Act, state-run vehicle inspection and maintenance (I/M) programs aim at preventing both manufacturers and consumers from circumventing or tampering with emissions control technology. Recent manufacturer cheating scandals, however, were detected by means other than I/M programs, and much I/M enforcement has been targeted at relatively low-level offenses. This Article traces the evolution of the I/M program and examines whether it currently provides benefits greater than its costs to vehicle owners, using Utah’s Wasatch Front (which includes Salt Lake City) to illustrate how the program operates in practice. It concludes that there is little current information to support or reject the efficacy of the I/M program, and that a fresh look is warranted to improve its effectiveness.