Vehicle detector and identifier for toll calculation - uses angled piezoelectric cable in conjunction with photo-detector height sensor and a inductive loop to identify vehicle type

摘要

The motor vehicle detector uses a piezo-electric cable set into the road surface and angled at approximately 85 degrees to the direction of the roadway to assist in discrimination of the vehicle type. The cable is installed in conjunction with an inductive loop set in the roadway and a photodetector by the road. The vehicle data gathered is used to compute the appropriate toll as the vehicle approaches the entrance to a toll road. Each vehicle axle gives two pulses because of the angled piezoelectric cable, and an electronic circuit divides the pulse count by two, rounds it to an integer and combines the information with the height sensor data to determine the vehicle type. The inductive loop detects the space between vehicles.