Low and hi-speed weigh-in-motion systems: a performance comparison

Weigh-in-motion (WIM) systems have been developed to perform continuous and automatic traffic monitoring, in terms of number, type and axial load. They should identify the dynamic load due to passage of a vehicle above the sensors and obtain, through appropriate data processing algorithms, the static load in real time. The sensors for axle weight measuring can be based on different technologies. The most used are piezoelectric sensors, quartz sensors, optical fibres, traditional load plates or load cells. Two weigh-in-motion systems, installed in a logistic platform (the freight village of Turin – named S.I.TO.), have been tested in terms of weighing accuracy. The accuracy assessment is based on the evaluation of the errors made by the systems in the estimation of the weight of three different reference vehicles: a 5-axle heavyweight truck, a lightweight van and a forklift. After a statistical evaluation of the two systems, a direct comparison is carried out and reported.