SIMULTANEOUS OPTIMIZATION OF TRAFFIC SIGNAL TIMINGS AND SUB-AREA DECOMPOSITION IN URBAN ROAD NETWORKS

For the purpose of implementing the coordinated traffic signal control, urban road networks in Japan are divided into several sub-areas. Each sub-area consists of a series of signal intersections. The traffic signal timing is optimized within each sub-area and reflects the local traffic situation. Since there is no well-established method of decomposing a traffic network into sub-areas, the decomposition is determined by skillful engineers based on their experience. This paper proposes a new method of decomposition, which is based an effectiveness index reflecting the traffic delay and the topological structure of the sub-area network. To evaluate the performance of the authors' approach, simulation experiments are carried out for an actual road network. The results show that the decomposition obtained by their method outperforms the conventional decomposition in terms of the employed performance index.