An investigation was undertaken to sort the efficiencies of different types of weigh-in-motion (WIM) systems commonly used for enforcement of commercial vehicle operations. Weigh station microsimulation model WESTA (WEigh STAtion) was used. The investigation focused, in particular, on the effect WIM system accuracy has on the effectiveness of presorting commercial vehicles before they approach a weigh station. WESTA simulations were performed, with and without main-line WIM, on a typical commercial weigh station facility across a range of commercial truck volumes (200, 400, and 600 Class 9 trucks per hour) and WIM system accuracies (ASTM Type III and Type I WIM). Three evaluation criteria were used: (a) number of compliant trucks required to report to the station, (b) number of overweight trucks instructed to bypass the station, and (c) time the weigh station remained open. It was found that weight enforcement efficiency improved with WIM. The improvements in efficiency translate into considerable savings for both the weight enforcement agency in relation to improved enforcement effectiveness and protection of the infrastructure and for the trucking industry in relation to reduced user-delay costs. It was also found that higher WIM system accuracy results in higher agency and user savings.
Abstract