Spread And Treatment Of Urban Traffic Congestion

The rapid development of the economy has raised the living standard of the citizens, butit also brings some negative effects on the environment of the city, e.g. the ownership of thecar present a ‘blowout’growth. However, the network of road is limited, the congestion in thecity is a common phenomenon in every city in different degrees. The congestion has turned tothe inefficiency of the road network, which limited the development of economy in return. Itis to spoken that the congestion in the city has become the issues which needs to be settledurgently.Firstly, the concept of congestion was clarified in this paper. The causes of congestion,the parameters to evaluate it and the structure of road network were also analyzed.Based on the Cell Transmission Model (CTM), this paper has researched thecharacteristic of the congestion caused by the sudden event. Combined with the road networkstructure of Xi`an (checkered road network), this paper selected the area of ‘Chang`anFlyovers-Xiaozhai Cross-2nd of the Wei Street Cross-Wujiafen-Television Tower’ to analysisthe characteristics of the congestion propagating. It has analyzed the effect of the proportionof the length of the divide area and the width of the parking line to the congestion propagatingthough the result of the simulation. The result has provided the design of the length of thedivide area and the width of the parking line a reference. Besides, this paper has analyzed therelationship between the fault-clearing critical time and the length of the parking line, and hasprovided the reference time domain to deal with the sudden event.At last, the method of the signal timing based on the CTM was proposed. This methodwas selected by comparing the advantages and disadvantages of the dynamic signal timingwith the static signal timing. As for the calculation of the key parameters (capacity of theflowing out of the cell, prediction of the flow in the cross, the average delay of the car, etc.)was discussed. The optimization of the timing signal was analyzed based on the practicalsituation of Xiaozhai cross in Xi`an. Then the effect of the optimized signal on the average delay of the car was also analyzed. The result shows that the optimized signal is able tobalance the delay of car in every entrance of the cross relatively, and optimize the utilizationof the time and space in cross, which will achieve the improvement of the traffic efficiencyand also provide a solution for the congestion of the city.