TRAFFIC MONITORING SYSTEM WITH REDUCED COMMUNICATIONS REQUIREMENTS

Monitoring of traffic on selected routes requires little communication time, through reporting only instances of abnormal speed. During a calibration phase calibrant vehicles are operated along the selected routes with sufficient frequency and for enough days to provide meaningful data. Each calibrant vehicle carries a differential GPS receiver for measuring location accurately. Average speeds for intervals of, for example, 15 seconds, are stored, with the time and place of observation. The data from all calibrant vehicles are then analyzed to determine patterns of mean speed and bandwidth. In the monitoring phase probe vehicles are deployed, each carrying similar GPS, a computer in which the patterns are stored, and a radio for automatically reporting speeds which are out of bandwidth for that time and place.