Operation Analysis of the Electronic Screening System at a Commercial Vehicle Weigh Station

Electronic screening (e-screening) sorts and diverts commercial vehicles that have a high likelihood of being overweight into a weigh station using weigh-in-motion technology. E-screening is known to add significant efficiency in operating weigh stations by allowing eligible trucks to bypass the in-station inspection, hence reducing the congestion at the weigh station. The primary goal of this study was twofold: (a) to develop a simulation model for describing the e-screening operation at truck weigh stations and (b) to analyze and evaluate the weigh station operation with varying values of affecting factors including the transponder penetration rate and the weigh-in-motion weight threshold. This study focuses the e-screening operation at a small weigh station with relatively short queuing area and heavy truck volumes, which is inevitably vulnerable to truck overflows and is sensitive to the prevailing transponder penetration rate and the weigh-in-motion threshold. The simulation results reveal that an e-screening operation can substantially improve the overweight enforcement and can reduce the travel time of legal trucks passing the test weigh station. The simulation results also demonstrate that properly adjusted weigh-in-motion thresholds can effectively enhance the overweight enforcement by preventing overweight trucks from being granted a false green light as a result of the erroneous weigh-in-motion measurement error. The study results also indicate that with the transponder penetration rate equal to or less than 20%, the e-screening benefits are relatively insignificant and adjusting the weigh-in-motion threshold may further deteriorate the enforcement efficiency.