Research On Traffic Bottleneck Identification And Dispersal Strategy Based On DTA In City Center District

City central district is the core region of a city structure and the most important part of the city function. It reflects the level of a city's social and economic development,undertake the responsibility to operate a city's economy. It can be used as a symbol of prosperity in a region. But,becouse of the characteristic of city central district,it attracts a lot of car flows and people. It has been become the region which is easy to produce traffic jam.So it is necessary to improve the traffic of city central district.In urban central district,Traffic bottleneck is is the key point of traffic system,if the traffic system of city centre district is compared to a barrel, the traffic bottleneck can be as the shortest board of the barrel.The efficiency of the whole system are subject to traffic bottleneck. This paper takes the bottlenecks as the research object,begin from the study on traffic bottlenecks identification methods, takes suppressing the traffic bottlenecks produces in the network as the target,probes into congestion bottleneck identification and leading decision.Firstly, previewing and analysing the exiting models, this paper brings forward the function of link travel time according to the theory of traffic flow wave, and gives computing and processing method. the functions of link travel time given in this paper includes two parts,one is the vehicle running time on non congest link, the other is the delay time in downriver crossover.And the traffic simulation software VISSIM is applicated to analysis the function of link travel time. According to the simulation result,the fuction of link travel time has been put forward is a good way to describe the average link travel time.Secondly,after the building of the travel time impedance function based on the theory of traffic flow,built the stochastic dynamic traffic assignment model and design the model algorithm based on the Logit model.It is used to investigate the problem of congestion bottleneck identification under dynamic stochastic user equilibrium (DSUE) condition. The relationship between traffic demand and bottleneck formation is highlighted. Furthermore, the process of bottleneck growth and distribution in the network is illustrated. Moreover,this paper proposes a way to identify the primary congestion and secondary congestion based on the study on the diffusion of traffic congestion.Finally,according to the characteristics of city central district,combining with the mechanism of traffic bottlenecks in the central area, proposes the strategies to ease traffic congestion in macro level,then, presents a congestion dispersal strategy based on congestion valid bottleneck identification.it can save the valuable time of traffic congestion dispersal, improves the utilization efficiency of traffic management resources.