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A Comparison of Private Garage and Centralized I&M Programs
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1979 by SAE International in United States
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A fundamental decision to be made in developing a motor vehicle Inspection and Maintenance (I&M) program is whether a “centralized” or “private garage” program will be used. Under the centralized approach, the state or a state contractor operates a network of single purpose “Inspection Centers” to inspect motor vehicles before the completion of the annual registration renewal process. After any repairs necessary to correct vehicles with excessive emissions are made at a facility of the owner's choosing, the vehicle must pass a reinspection at the Inspection Center. Under the private garage (decentralized) approach, both inspections and repairs are conducted by private repair facilities licensed by the state.
A comparison of a centralized I&M program and a private garage I&M program currently operating in California indicates that the centralized program is providing over ten times greater emissions reductions. The superior performance of the centralized program appears to be due in large part to the fact that emissions related defects are more efficiently and reliably identified with the use of highly automated Inspection Centers. The fact that vehicles with excessive emissions are independently reinspected to check the quality of the repairs performed also appears to be a factor contributing to the superior performance of centralized I&M programs.
An analysis of the potential for upgrading both programs indicates that the private garage approach is unlikely to ever be competitive with a centralized I&M program.
CitationAustin, T. and Rubenstein, G., "A Comparison of Private Garage and Centralized I&M Programs," SAE Technical Paper 790785, 1979, https://doi.org/10.4271/790785.
- “Forward to the State of California's 1979 State Implementation Plan Amendments in Response to the Clean Air Act Amendments of 1977” California Air Resources Board July 1979
- “Public Hearing on Proposed Changes to Regulations for Exhaust and Evaporative Emission Standards and Test Procedures for 1979 and Subsequent Passenger Cars, Light Duty Trucks, and Medium Duty Vehicles,” California Air Resources Board staff report #76-22-2 October 1976
- “Continuation of Public Hearing on Proposed Changes to Regulations Regarding Allowable Maintenance During New Vehicle Certification of Light-Duty and Medium-Duty Vehicles,” California Air Resources Board staff report #77-12-1 April 1977
- Gunderson J. A. et al “Inspection/Maintenance (I&M) Program as a Viable Cost-Effective Emissions Reduction Option,” SAE Paper 790649 Passenger Car Meeting Dearborn, Michigan June 1979
- “Exhaust Standards for the Mandatory Vehicle Inspection Program,” California Air Resources Board staff report September 29 1978
- Rubenstein G. et al “Vehicle Inspection and Maintenance - The California Program,” SAE Paper 760557 Fuels and Lubricants Meeting St. Louis, Missouri June 1976