Synergistic Optimizaiton Of Short Lane Length And Timing Parameters For An Intersection Group With Coordinated Signals

Urban traffic congestion is worsening and its main reason is that the road network cannot meet the rapid increase of traffic demands. Intersections, as the bottlenecks in a road network, become to be the critical points for traffic congestion. Usually, the number of lanes on an approach is added to increase the capacity of an intersection in order to alleviate traffic congestions. However, due to spatial constraints, such lanes cannot usually be expanded to full lanes. Thus, such lanes are called short lanes. Therefore, the optimal allocation of the time and space resources are investigated for an intersection group with coordinated signals and short left-turn lanes by synthetically considering short lane length and signal timing parameters in this paper.This paper was divided into four chapters. In the first chapter, the background and significance of the research, the research achievements of short lanes, and the objectives and contents of this paper were presented. The parameters of signal timing and the performance indices of traffic flow operations were summarized in the second chapter. Aiming at two adjacent intersections with the coordinated signals and short left-turn lanes, three optimization models were formulated to jointly obtain the common cycle length and green splits in the third chapter. A case was designed to verify the effectiveness of the optimization models. The signal timing plans for each intersection were obtained respectively by using the proposed optimization model and the Webster model. Then, the traffic operations under the two signal timing scenarios were simulated by using the VISSIM software on the basis of the calculated offsets between coordinated phases which are obtained the existing method.In Chapter4, the optimization models were further formulated when considering an intersection group with three intersections or more. An intersection group with three intersections as a case was designed to testify the efficiency of the proposed models.The research results show that the optimization models can effectively reduce the average delay per vehicle and slightly increase the capacity of an intersection. Therefore, the optimization models can optimally allocate the time and space resources for an intersection group with coordinated signals and short left-turn lanes, and provide an effective method for alleviating urban traffic congestion.