Failure Correlation Analysis Of Urban Road Network Based On Dynamic Traffic Assignment

With the accelerating process of urbanization, the expanding of urban traffic volume, transport supply and demand imbalances have become increasingly prominent. Which causing the traffic congestion ordinarily, especially combined with frequent traffic accidents. How to solve the traffic congestion in two situations becomes the focus of international hot topics. The first step is to acquaint traffic congestion if you want to solve it, then analysis the generation and diffusion mechanism of congestion. The paper obtains an effective way to alleviate traffic problems that is based on the above understanding, from the perspective of failure correlation of traffic congestion.This study based on complex traffic characteristics of urban road network in peak phase. First of all, the paper has to summarize the basic theory and method of failure correlation in general system, with its own characteristics of road network, then the paper designs the model to analyze the failure correlation of urban road network. Secondly, the paper carries out a further discussion about the model and implementation, and then gets the data of flow rate. This paper delimits failure criterion of link travel time, puts forward cross correlation coefficient and autocorrelation coefficient to describe the failure correlation of road creatively, and decides to estimate the failure correlation of network with probabilistic network. Thirdly, the paper studies the diversification of failure correlation around the accident section with different levels of emergency, analyzes road network variation and failure correlation spread with four conditions which is extent and lasting and functional level of local road network and information guidance separately, finds the longer and the greater degree of section of failure, the more serious failure of surrounding road network; appears cascading failure and closed-loop congestion more easily. And if improves the proportion of information guidance and extent can ease failure correlation and jams.The main innovative researches of this paper are as follows:1. We can get the result is that the lower functional level of local road network, the smaller degree of failure dependence, which after the research about the failure correlation in different functional levels. Then the paper studies on the connection between the failure correlation and the gradation of the road network functions.2. We can get the result is the information guidance can reduce the failure correlation after which research about the failure correlation under the conditions of traffic guidance, so we can use this means to ease congestion.3. According to the analysis method of failure correlation, the paper has optimized the calculation method of classical "K-path" in traffic guidance, the results show that it is better to avoid high-risk failure elements after adding sections of failure correlation factors, and we can get the more reliable results and higher reliability.