Research Of Urban Traffic Trunk Coordination Control Strategy Under Oversaturated State

With the development of economy and society, the number of vehicles in urban city is increasing nowadays. The contradiction between traffic supply and demand has become prominent increasingly. Traffic congestion problems such as environmental pollution and energy consumption have become a universal challenge to be solved, particularly in developing countries. In recent years, saturated traffic has become widespread traffic phenomenon in China, especially urban arterial roads usually are in oversaturated traffic state. Congestion could lead to the event of large-scale traffic crashes easily, which impacts the efficiency of urban transport. The discussion of strategies of oversaturated urban arterial cooperative control plays an important role in improving urban traffic on practical significance.To alleviate saturated traffic, the saturation of key sections is reduced in this thesis. Sub-regions was analyzed by reduce saturation of roads to alleviate saturated traffic. Firstly, urban arterials were partitioned into several sub-regions in the way of dynamic division on the basis of critical section. Traffic delay model and cooperative control benefits model were set up through analyzing the connection of change of signalized intersection capacity and sub-regions delays. Then, according to the distribution law of saturated section in a sub-region, the cooperative control tactics using better Webster calculation were adjust to traffic control. Finally, this paper set up a dedicated simulation platform and collected actual urban road network traffic data. And the result shows that the control tactic in this paper can alleviate over-saturated traffic and improve the efficiency of urban transport system. The main work of this paper is as follows:(1) Review the urban trunk cooperative control in detail, and deducing the main research contents after making a discussion on the difficulties and problems in this field.(2) By analyzing the conception of critical section, this paper showed the selection principles at an aspect of dynamic division and static division and came up with a method to partition urban arterials into several sub-regions.(3) On the fundamental of the connection of signalized intersection capacity and sub-regions delays, traffic delay model was set up. Cooperative control benefits model was brought forward by analyzing different cooperative control aims of sub-regions.(4) The different control methods were used for different situations of sub-regions. In addition, the cooperative control tactics using better Webster calculation was set up according to the better calculation way of section saturation and the connection of signalized intersection capacity, sub-regions trunk delays and cooperative control period.(5) This paper set up a dedicated simulation platform and described compositions and functions in details. And the research used the actual urban road network traffic data to demonstrate the effectiveness and feasibility of this cooperative control tactic.