The purpose of the Motor Vehicle Inspection Experiment was to provide meaningful data upon which the California Highway Patrol could base an evaluation of the effectiveness of its random Motor Vehicle Inspection program. The primary question under examination was, "What effect do various levels of Motor Vehicle Inspection have on the maintenance of vehicles?" Analysis and findings of the experiment were based upon an evaluation sample of 4,120 inspections performed during the three days immediately following the experiment. The findings of the Motor Vehicle Inspection Experiment can be summarized as follows: 1. Vehicle maintenance is directly related to intensity of inspection. 1. An attempt was made to determine if there was a "halo" or carry-over effect from higher levels of inspection. The results of that analysis were inconclusive due to a number of uncontrollable extraneous variables. 3. In half of the inspected counties, during the experiment, vehicle lighting equipment was not examined. This was designed to determine if all items of equipment needed to be inspected to ensure their maintenance. Data analysis showed that there was a significant carry-over effect. 4. Distributions of violations by type of defect noted were examined to determine if changing inspection levels would cause a shift in the type of defects occurring. Results of that examination showed no significant discernable shifts. 5. Significant increases in inspection effectiveness can be realized, without increases in manpower or costs, by selecting older vehicles for inspection. Since the older 50% of the vehicle population has about 75% of the safety-relted defects, random vehicle inspection will be more productive if it is concentrated on the older vehicles. The conclusion of the study is that a selective roadside inspection program, concentrated on older vehicles, would be the most efficient and cost-effective Motor Vehicle Inspection program for California. The recommendation of this report is that, if California is to continue a Motor Vehicle Inspection Program, it should retain a random roadside inspection format, but should concentrate on inspecting older vehicles.
Samenvatting