Procedures to Evaluate the Effectiveness of PMVI

Twenty-eight states and the District of Columbia have some form of PMVI system. Of paramount concern is the question of how effective the state PMVI system is in suppressing vehicle defects.

A technique has been developed by which a state can evaluate the effectiveness of PMVI in reducing vehicle defect level below that which would exist without inspection. By sampling vehicle-in-use condition as a function of time since last state inspection, a data analysis-evaluation procedure can be used to determine both quantities of interest -- average safety status of cars with inspection and the same condition without inspection. Data collection procedures consistent with the evaluation objective are also presented.