Continuous Calibration Weigh-in-Motion System Using Static Weight Data

This paper presents an advanced approach for continuously calibrating weigh-in-motion (WIM) sorting systems using the static scale data generated by downstream truck inspection stations. It presents an automated closed-loop algorithm developed to accurately match vehicles at the two locations and use the data at the static weigh scale as the WIM calibration reference through a feedback algorithm. Calibration is carried out automatically by minimizing the error between WIM and static gross vehicle weight (GVW) measurements by vehicle class and speed. The large sample of vehicles involved in these calculations ensures high reliability in the calibration factors and the resulting accuracy in WIM measurements. The proof of concept is provided by analyzing data from eight multi-lane WIM systems in three States. It is demonstrated that the system can maintain indefinitely the accuracy of WIM systems in measuring GVW and axle loads without the need for periodic on-site calibrations involving test trucks.