Recent legislation has encouraged the increased operation of trucks (defined here as vehicles having six or more wheels in contact with the road and a gross vehicle weight greater than 10,000 lb) on Interstate and primary highways. This has affected safety and the quality of traffic flow on multilane highways. Imposing certain restrictions on truck operations on these highways has been identified as a way to reduce this effect. However, the overall impact of these restrictions on safety and traffic flow has not been fully studied. For example, restricting trucks to specific lanes or lowering their speed limit could have varied effects on traffic. The primary objective of the research described in this paper was to provide information on the nature and extent of the effects of such truck control strategies on traffic flows, speeds, headways, and accident patterns. Simulation was used to study these effects on multilane highways. The results did not indicate any safety benefits from the imposition of these strategies but suggested that the potential for an increase in accident rates would be created, particularly if the strategies were imposed on highways with high volumes and a high percentage of trucks.
Abstract