Abstract:
This research is a study of methodology to design optimum cycle time for congested intersection/s employing road network within Ratchadapisak Ring Road in Bangkok as a study area. At present, traffic signal are controlled manually by policeman resulting in excessive traffic congestion at intersection/s and in the whole network. Basic strategy for this study to design optimum cycle time is somewhat changing from normally practice. The new strategy is to maximize throughput resulting in minimize total delay of the intersection/s network. A relationships between departure flow rate and time were investigated and differentiated to compute optimum cycle time. After that, evaluation of the new optimum cycle time and existing cycle time were carried out within the study area on existing traffic simulation program "Transyt/8". Results of the analysis for congested network within Bangkok Metropolis showed that optimum cycle time for study area should be 140 seconds. Also results of the evaluation showed that, by using 140 seconds cycle time, total time spent for the study area decreased by 6.3% ; mean journey speed increased by 8.3% ; total uniform delay decreased by 43.9% and performance index decreased by 18.4%. This meant that the new traffic condition after using 140 seconds cycle time at all studied intersections would be somewhat better than the existing condition.