Microprocessor and PC-based vehicle classification equipments using induction loops

The Laboratory of Traffic and Transportation Engineering of the Helsinki University of Technology (HUT) has developed and built up already three generations of traffic analysers for field research needs. All these equipments have in common that they use induction loop technique to detect the traffic and microprocessors to process the signals given by the detectors. The paper summarises some of the experience gained on building and using these traffic analysers. It deals with general principles and aspects of traffic flow research. The hardware and software of the analysers, especially the latest and most advanced one, are described