Test of WIM sensors and systems on an urban road

This paper describes a large-scale test of six WIM systems and four additional sensors on an urban roadway in Zurich, Switzerland. Gross weights from some thousands of statically weighed vehicles were used to determine the levels of accuracy for each system, with reference to the new draft of the European specification on WIM (C0ST323). The accuracy of axle weights was not tested. The WIM sensors, which included one prototype, were tested with the assistance of a recording and processing device supplied by the organiser. Most systems encountered some problems, failures and faults, under the carefully controlled conditions of the 30-month test. However, these were generally solved by the suppliers after some delay. Statistics are provided on overall levels of accuracy and on trends with season and time. In addition, a brief history of system malfunctions and failures is provided. Nevertheless the scope of the conclusions is limited by the traffic conditions and the test plan.