In 1986, International Road Dynamics was contracted by the Transportation Development Centre to develop and test a piezoelectric weigh-in-motion (WIM) system that would weigh, classify and count vehicles, and continuously collect data on traffic operating at normal highway speeds. A full-scale system was installed for testing and demonstration purposes on six lanes at a site on Highway 7 north of Toronto. A first test site for the piezoelectric cables was provided and prepared by the Saskatchewan Department of Highways and Transportation; the full system demonstration site was by the Ontario Ministry of Transportation and Communications. The work included the design and construction of prototype electronic hardware to gather signals from the piezoelecric cables and other system components. Software was developed to interpret the cable signals and to provide a user-friendly method on monitoring the scale output. The weigh-in-motion scale could be accessed remotely using a standard computer terminal and telephone modem. Full system tests found that the piezoelectric WIM reliably measures any vehicle weight normally encountered on North American highways. It classifies vehicle types and provides weight measurements with an accuracy comparable to that of existing platform WIM systems. Weight measurement variance, however, is double that of platform WIM scales. Its cost is about 25% that of conventional systems.