Truck Safety

Twenty states, most of them in the West, allow longer combination vehicles to operate but have very different restrictions on the types of vehicles allowed, the routes on which they can operate, and their length and weight. Although such vehicles have been on the roads for more than 30 years, little definitive information on their safety is available. Due to data problems and different study approaches, existing studies on the accident rates of multiple-trailer trucks have reached widely different conclusions about the safety of longer combination vehicles. Longer combination vehicles may be less stable and maneuverable than single-trailer trucks, which can affect their safety. However, the operational characteristics of longer combination vehicles can be affected by many factors, including the type of vehicle, the driver, the distribution of the load, the equipment used, and road conditions. Until data shortcomings are overcome, the actual impact of all types of longer combination vehicles on highway safety will remain unknown. Congress has passed legislation prohibiting the expansion of longer combination vehicle use. Although this law also requires several actions to improve transportation data, it does not specify the kind of truck data required.

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.

Recommendations

Our recommendations from this work are listed below with a Contact for more information. Status will change from "In process" to "Open," "Closed - implemented," or "Closed - not implemented" based on our follow up work.

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