Research On Road Network Traffic Signal Control Technology For Small And Medium-Sized City

With the development of the city, the growth of vehicle and the density of the road network increase even more rapidly. In addition, the traffic demand increases also rapidly. And the traffic problems become increasingly severe not only in the big cities, but also in the small city and these problems have begun to plague the development of the city and gradually become the important factors restricting the economic construction of the city. Small and medium-sized city road network traffic control technology has gradually become a new research hotspot in control domain and traffic engineering.This paper in view of the small and medium-sized city road network traffic flow characteristics uses the existing road network control area dynamic partitioning technology to divide the road network into several control area and uses the existing traffic state identification technology to identify the state of control sub area, namely "low saturated state""middle saturated state" or " saturated state". Then adopt different control strategies according to different control targets and different states.In this paper, the main work are as follows:1in-depth analysis of the characteristics of small and medium-sized city road network traffic flow, put forward the coordinated control thought that adopt different control strategy according different control targets and different states;2under the low saturated state, with "the minimal parking rate" as the goal, use "green wave" coordination principle to get fewer stops of the vehicles in the traffic control sub-region. It presents the road network coordinated control strategy, parameter optimization of traffic signal and the process of coordination and optimization;3under the middle saturated state, with "the maximum service efficiency" as the goal, optimize the signal cycle by establishing saturation model, optimize the green time by establishing Webster delay model, optimize the phase by establishing a combined model of section delay model and number of stops model. It achieves a collaborative optimization of the intersection signal control sub-region and makes the traffic in the best traffic state;4under the saturated state, with "the maximum queue length" as the goal, use "red wave" coordination principle to avoid the traffic congestion that has occurred or eliminate the occurrence of congestion. It presents the road network coordinated control strategy, parameter optimization of traffic signal and the process of coordination and optimization.