High-Speed Weigh-in-Motion System Calibration Practices

Abstract

Weigh-in-motion (WIM) is the process of weighing vehicle tires or axles at normal roadway speeds ranging up to 130 km/h (80 mph). WIM systems consist of sensors embedded onto the pavement surface and a data acquisition system equipped with software capable of processing sensor signals into weight, computing additional traffic data elements, and summarizing them into various database formats. There is an urgent need for ensuring WIM data accuracy. This is accomplished through routine WIM system calibration and periodic WIM data quality control. The way these tasks are carried out varies widely between agencies. This study synthesizes the state of the practice in high speed WIM system calibration. The study is likely to be of interest to those responsible for long-term pavement performance, pavement design, bridge design, monitoring highway usage, highway cost allocation, and enforcement of truck loads. Two main tools were used in conducting this study—a thorough review of the European and North American literature on the subject and an on-line survey addressed to highway and load enforcement agencies administering WIM systems in the United States. The survey was supplemented by telephone interviews.