Queue spillback is a challenging issue in operating truck weigh stations.Truck volumes exceeding the station capacity cause queue spillback onto the highway mainline and weigh stations inevitably allow queued trucks to bypass the overcrowded station. As a result, the enforcement effectiveness can be severely compromised. Electronic screening systems provide weigh stations with an automatic enforcement mechanism that sorts and diverts onlyapparent overweight trucks for further inspection at the weigh station. The escreening benefit, however, can quickly diminish if truck volumes continue to overflow the station capacity especially if the weigh station has limited space to accommodate waiting trucks. This paper presents a dynamicWeigh-In-Motion (WIM) threshold control algorithm. This algorithm adjuststhe WIM threshold to regulate the incoming truck flow to the weigh station aiming for maximizing the utilization of the weigh station capacity. Thealgorithm consists of several parameters that determine stability, response time, and amplitude of the feedback signal. The impact of regulator parameters is tested and demonstrated through a sensitivity analysis. This paper presents only preliminary results. In the future, a simulation environment will be established to evaluate the algorithm performance. An optimalparameter set will be determined through further analysis and the algorithm will be tested against an existing method using a pre-set WIM threshold.
Abstract