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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Truck and Bus Maintenance Requirements and Their Impact on Safety


The goals of this study are to: (1) understand the impact of maintenance on safety-based crashes; (2) develop an operational definition of systematic maintenance; (3) evaluate the effect of current regulations on preventative maintenance intervals, preventative inspections by trained mechanics, and inspection facilities; (4) determine the maintenance standards of best performers; and (5) determine the range and role of annual State inspection programs.


Vehicle maintenance (e.g., brakes, lights, other mechanical defects, and load securement) is one of the seven Behavior Analysis and Safety Improvement Categories (BASICs) for Carrier Safety Measurement. In January 2014, FMCSA published the Carrier Safety Measurement System (CSMS) Effectiveness Test by BASICs Study. This published study showed that motor carriers targeted for interventions due to vehicle maintenance have a 65 percent greater future crash rate than the national average.


The current study is analyzing the impact of preventative vehicle maintenance of large trucks and buses on safety, to include not only violations that are serious enough to be listed as out-of-service (OOS) criteria, but also other vehicle maintenance issues which have been found to cause or contribute to crashes. The study seeks to understand the effect of current regulations on maintenance and consider whether new or revised OOS criteria are needed. New or revised OOS criteria may include combinations of vehicle maintenance issues. This study is also assessing the prevalence and nature of State inspection programs and the maintenance standards of the safest carriers.


A report that analyzes the impact of vehicle maintenance on safety and recommends whether new or revised OOS criteria are needed. Additionally, a review of inspection and maintenance practices of States and safe carriers, respectively.



October 2016: Kick-off meeting
November 2016: Draft work plan to be peer-reviewed
February 2017: Final work plan (peer-reviewed)
April 2017: Literature review completed
August 2017: Draft OMB PRA Information Collection Requests Parts A & B submitted
September 2017:  Preliminary analysis of data from CSMS & MCMIS
November 2018: Development of public-use data set
March 2019: Final report and final briefing due


FY16 Funding: $335,627

Project Manager:

For more information, contact Quon Kwan of the Technology Division at (202) 385-2389 or


Virginia Tech Transportation Institute