A CONTROL STRATEGY FOR A CONGESTED, COMPUTER-CONTROLLED TRAFFIC NETWORK

IT IS SUGGESTED THAT TRAFFIC LIGHT GREEN TIMES SHOULD BE ADJUSTED TO BALANCE THE QUEUES ON ITS VARIOUS ARMS DURING CONDITIONS OF HEAVY CONGESTION. IN THIS MANNER THE VEHICLES QUEUES MAY BE ARRANGED SO THAT THE MINIMUM NUMBER OF JUNCTIONS ARE BLOCKED BY WAITING VEHICLES. THIS STRATEGY INVOLVES THE USE OF SAMPLED DATA FEEDBACK LOOPS AT EACH JUNCTION AND THERE ARISES THE POSSIBILITY OF INSTABILITY DUE TO THE POSITIVE FEEDBACK EFFECTS OF TRAFFIC COUPLING. THE DYNAMIC BEHAVIOR OF AN ISOLATED JUNCTION IS FIRST CONSIDERED AND THE ANALYSIS IS THEN EXTENDED TO A NETWORK OF JUNCTIONS. IT IS SUGGESTED THAT THE STABILITY OF THE NETWORK MAY BE IMPROVED BY THE USE OF COORDINATING SIGNALS TRANSMITTED BETWEEN JUNCTIONS, AND STABILITY CRITERIA FOR THE CONTROLLER PARAMETERS ARE ESTABLISHED. /RRL/A/