Research On Traffic Signal Control Methods Of Trunk Road Under Oversaturated State

The problem of urban traffic congestion has become a hot and difficult problems that affect social progress must be resolved. And urban traffic in peak period, trunk roads as traffic network aorta usually overload running, once the weak link in the traffic jams are not solved, it will make congestion spread over interrelated road sections and cause traffic bottleneck, which is to be studied in this paper.Traffic signal control can effectively improve the road traffic order and efficiency. Current research in this area is rich in content, focused on the traffic network, randomness and dynamic and so on, develop the optimal solution of the traffic signal control, but to this control strategy in urban trunk roads traffic saturated or nearly saturated it is difficult to effectively ease the congested traffic flow. Therefore, to explore for traffic signal coordinated control strategy in urban saturated trunk roads is of great significance to improve and perfect the systemic of signal control method for urban traffic congestion, and improve the operating efficiency of trunk roads.This paper aimed at evacuating congested traffic flow of saturated trunk road, selected qualified connection sections to determine signal coordination control area, the use of the queue length defined coordinated control conversion conditions, and to coordinate and control the traffic bottleneck in oversaturated trunk roads. Specific research work including:the first analyze trunk roads traffic saturation to explore for signal control ideas on the bottleneck traffic. Secondly, select the connection sections according to relevance and storage fleet capacity to accommodate the traffic pressure from evacuation of a bottleneck with the coordinated control, use second-rate theory to calculate sections equivalent queue length, as the start and the end constraints of a coordination control. The paper also constructed iterative steps of signal control strategy in oversaturated trunk roads, detailed design signal coordination control method for the traffic bottlenecks upstream, downstream respectively, including the start and end conditions of the signal control, signal timing adjustment method. Finally, the paper also simulate signal coordination control method using VISSIM software,comparing common signals control method to verify its control effect.