A Computer Control Scheme for Critical-Intersection Control in an Urban Network

In periods of traffic congestion, residual queues at intersections or the blocking of lanes limit the efficiency of synchronized signalization. A computer control scheme is developed that concentrates upon providing real-time, traffic-responsive corrective action for a “critical intersection,” defined as a point in the network at which primary driver routes cross or those where congestion has arisen for other reasons, such as in the aftermath of an accident or stall. The sub-optimal scheme attempts to minimize the total delay, measured in vehicle-seconds, not only to all users of the intersection but also of accumulated delay at downstream intersections. Within upper and lower limits on the cycle time, the control of the traffic signal is variable split and variable cycle-length in response to traffic needs. A simulation evaluation of the method is given via several test cases, using as a base case actual traffic data from San Jose, California.