Vehicle Counting Overview

Vehicle counting is becoming a very common requirement for car parks regardless of the size. It is a fantastic convenience for visitors to be aware of the number of available spaces before they enter a car park, or venture into another section of the car park. Traffic monitoring on roads is becoming commonplace as highway authorities and council transport departments also strive to reduce congestion. For vehicles to be automatically counted, there needs to be a means of detecting them. The most common form of vehicle detection uses an inductive loop buried in the road surface. As a vehicle passes over the loop, the loop inductance changes causing the loop monitoring circuit (loop detector) to output a signal. If two such loops are placed very close together along the path of the vehicle, the direction in which the vehicle is travelling can be detected also. In car park applications, loops need to be placed in each exit and entrance lane as well as on ramps between levels. The counting system receives the signals from the loop detectors and maintains a count of vehicles entering and exiting each area. It then computes the date as necessary to provide the required display information and / or alarm signals.