The development of infrared detection systems for use in traffic control is traced and their advantages compared to other systems outlined. The dynamic passive infrared sensor system has been used widely in modifying traffic signal phases. Considerable effort went into the development of the static and dynamic passive infrared sensor which was able to detect vehicles stopping and to accurately count vehicles. This is achieved by processing signals of the same event seen by different sensors, one fast and very sensitive to intensity changes and the other slower but seeing the amount of thermal radiation. Uses for the static/dynamic model IR 222 based on this principle are discussed. Modifications in operation or planned are outlined. The use of dual channel static and dynamic sensors in the ROMANSE project is noted.
Abstract