REALBAND: an approach for real-time coordination of traffic flows on networks

An approach is proposed for real-time coordination of signal phase timings for a network. Currently, network coordination is done using off-line methods, such as MAXBAND, PASSER II, and TRANSYT, which are based on average traffic volumes for various movements. On-line approaches such as SCOOT adapt off-line methods by constantly inputting updated average volumes computed from detector data over the 'last' decision horizon. REALBAND first identifies platoons and predicts their movement in the network (i.e., their arrival times at intersections, their sizes, and their speeds) by fusing and filtering the traffic data obtained, from various sources, in the last few minutes. An approximate traffic model, APRES-NET, is used to propagate the predicted platoons through the network for a given time horizon. The signals are set so that the predicted platoons are provided appropriate green times to optimize a given performance criterion. If two platoons demanding conflicting movements arrive at an intersection at the same time, then either one or the other will be given priority for green time, or one of them is split to maximize the given measure of performance. This study discusses how such conflicts are resolved and the corresponding algorithmic procedure of REALBAND.