Truck Safety:

The Safety of Longer Combination Vehicles Is Unknown

RCED-92-66: Published: Mar 11, 1992. Publicly Released: Mar 23, 1992.

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Pursuant to a congressional request, GAO reviewed the safety of longer combination vehicles (LCV), focusing on the: (1) current extent of LCV use; (2) results of LCV safety studies; and (3) major operational characteristics that affect LCV safety.

GAO found that: (1) 20 states allow LCV operation, but they have different restrictions on the types of LCV allowed, the routes on which they can operate, their length, and their weight; (2) LCV safety studies have reached very different conclusions, with some studies finding that multiple-trailer trucks are less likely to be involved in accidents than single-trailer trucks, while other research indicates that multiple-trailer trucks are more likely to be involved in accidents; (3) a lack of adequate truck data and different study methodologies contributed to different research conclusions; (4) LCV safety tests indicate that multiple trailers are more apt to sway than single trailers, require a wider turn path, and are more likely to travel out of their lane; (5) LCV operational characteristics are affected by LCV type, the driver, load distribution, equipment used, and road conditions; and (6) projections of an increase in traffic density and a shortage of experienced truck drivers could impact future LCV safety.

Recommendation for Executive Action

  1. Status: Closed - Implemented

    Comments: The Federal Highway Administration (FHwA) is providing grants under the Intermodal Surface Transportation Efficiency Act of 1991 to states to adopt the uniform accident reporting form recommended by the National Governors' Association and data elements, which require reporting data on truck configurations. As of August 1994, 23 states had adopted the form and data elements. FHwA plans to continue its efforts to get the remaining states to adopt the uniform reporting practices. FHwA estimates it will take at least 2 years for this effort.

    Recommendation: To improve transportation data and to help determine LCV safety, the Secretary of Transportation should improve truck accident and travel data, especially as they relate to the reporting of nonfatal accidents, the estimates of truck travel, and the identification of truck configurations.

    Agency Affected: Department of Transportation


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