A STUDY OF ROAD DAMAGE DUE TO DYNAMIC WHEEL LOADS USING A LOAD MEASURING MAT. VOLUME 1: EXPERIMENTAL PROGRAMME, MULTIPLE-SENSOR WEIGH-IN-MOTION. FINAL REPORT

A wheel load measuring mat of total length 38 m, incorporating 96 capacitative strip Weigh-in-Motion (WIM) sensors was installed on a test track. A total of 650 test runs was performed on seven different articulated heavy vehicles, for a range of speeds between 8 km/h and 80 km/h. The wheel force data were analyzed to investigate the performance of the individual sensors and the design and performance of WIM arrays with up to six sensors. The strip sensors were found to be very reliable and to measure the dynamic wheel loads with an accuracy of better than 4%, based on the root mean square of the variance from the true value. A theory was developed for the design of multiple-sensor WIM systems and the experimental results were found to agree closely with the theoretical predictions. It is concluded that a good design for multiple-sensor WIM systems is to use 3 sensors, spaced evenly along the road. The sensors should be spaced according to a simple formula which depends only on the average traffic speed. The expected static axle load estimation errors for such a system are likely to be 30% to 50% of the errors of a single-sensor WIM system.