Regional Signal Coordination Control Under Mixed Traffic Condition

Currently, the exacerbation of urban traffic congestion problem has seriously affected the development of the city. Especially in the morning and evening rush hour, traffic flow changes frequently, and the urban road network is easy to fall into a mixed state, which part of the road network in the non-saturated state and part of the road network in the over-saturated state. In this case, the existing unsaturated coordinated signal control or over-saturated coordinated signal control separately applied to road network is difficult to satisfactory. In order to solve the above problems, based on the research status for the urban traffic signal control method at home and abroad, this paper respectively studies the existing road network coordinated signal control method applied to unsaturated traffic condition and over-saturated condition, finally proposes signal control method for road network coordination under mixed traffic state. The main research work includes the following three aspects:1. The green wave coordination control method based on subarea division that is applied to non-saturated traffic state is proposed. Establishing the different bandwidth optimization model on the basis of improving the traditional maximum bandwidth model, and further analyzing the control method suited for complicated arterial and its parameters optimization with the maximum bandwidth optimization model. Moreover, the subarea division method applied to unsaturated state are put forward. Simulation results show that the green wave coordination control based on subarea division is superior to the traditional green wave control.2. The control effect of the regional coordination splits adaptive control method based on linear quadratic optimal control in the over-saturated state is verified by the simulation research. This method uses store-and-forward model to describes operation dynamic of the traffic flow in the over-saturated state, and applies linear quadratic optimal control method to design regional coordination splits adaptive controller. The simulation results show that this method in the over-saturated state is superior to the traditional timing control.3. The regional signal coordination control method based on subarea division under mixed traffic condition is proposed. Firstly, by expatiating over-saturated traffic state identification algorithm, this article introduces degree of queue dissipation and congestion degree of overflow to quantitatively describe degree of intersection congestion, and then proposes two indicators including intersection congestion index and network congestion index used in hybrid state control region division. Relevant control method is adopted according to different state regions. Secondly, in order to solve real-time dynamic changes of the traffic flow status in road network, this paper gives subarea dynamic partitioning and adjustment method in the mixed traffic state. The mixed status regional coordination control system proposed by this article adopts hierarchical control structure, which includes the center control level, supersaturated zone and unsaturated zone control level, supersaturated zone and unsaturated zone coordination level, and intersection execution level. Each control level cooperates together to accomplish intelligent coordinated control of the complex regional road network. The simulation results show that intelligent coordination control for regional road network based on subarea division can effectively improve the efficiency of complex network.