Infrared Sensors for Counting, Classifying, and Weighing Vehicles.

摘要

In the study, five field tests were conducted to determine the feasibility of using commercially-available infrared light-beam sensors for counting, classifying, and perhaps weighing vehicles. It was demonstrated that a single, reflex-type infrared sensor mounted just off the shoulder and working off a retro-reflective raised pavement marker in the center of the outside traffic lane can be used to count the tires on one end of each axle of a moving vehicle with accuracy comparable to human observers or to a flush-mounted ;iezo-strip sensor. Sensor installation involved no pavement cuts and only minimal interference to traffic. Tests were not conducted in snow or heavy rain. Arrays of two or more infrared light-beam sensors can be used to sense vehicle-body presence, to calculate vehicle speed, axle spacing, and tire-contact patch dimensions, to indicate single or dual tires, to detect direction of vehicle movement, and to sense over-height vehicles. Off-shoulder reflex-type infrared sensors with retro-reflective raised pavement markers operated for up to three months without cleaning. A two-sensor array tested in the Houston high-occupancy-vehicle (HOV) lane indicated promise as a replacement for loop-detector arrays.