Empirical Analysis For The Topology Structure Of Highway Networks

With the increase of traffic mileage and traffic flow in expressway, expressway plays more and more important role in transportation. The expressway has the characteristics of convenience, high speed and strong traffic capacity, which provides great convenience for people to travel. However, once expressway traffic accidents and natural disasters and other emergencies occur, these situations will easily lead to large areas of traffic jam and even traffic gridlock. Analysis on the structure of freeway network, effectively identification of key nodes that easily lead to traffic congestion, and especially strengthening the key nodes, can greatly improve expressway traffic capacity. According to the national science and technology support program--Research and development of multi-scale highway network operation situation analysis technology and system based on big data, this paper makes a deep analysis of the freeway network structure.Firstly, we analyze the influence factors of expressway. The basic model of complex networks and the representation of graph theory are studied. We master the method of comprehensive evaluation, and sum up the research results of related fields at home and abroad. This lay the foundation for the next step to establish evaluation index system of freeway network structure.Secondly, starting with the analysis method of freeway network, namely complex network, this paper discusses the statistical indices of complex networks. Based on the topological structure of freeway network and the actual functional properties, we define abstract and physical network topology, and construct the evaluation index system of the local and the overall characteristics for the nodes and links.Then, the analysis methods of key nodes and links are summarized, and their definition are given. We evaluate the key nodes by the importance of nodes, and four modes of analyzing the importance of nodes and links are established respectively. That is betweenness, the spanning tree based on the method of deleting, the road network efficiency based on the deletion method and the cohesion degree based on the shrinkage method. An innovative approach is proposed to analyze the importance of nodes, that the freeway network efficiency is applied to the node contraction method.Aiming at comparing the advantages and disadvantages of various analysis methods, we compare the relationship between spanning tree of node deletion method and freeway network efficiency, between efficiency cohesion of node contraction method and freeway network efficiency, between road network efficiency and network performance analysis method of node deletion method.In order to carry out the classification of nodes in different cities, this paper innovatively proposes the K-Means cluster analysis from two aspects. The node importance by the spanning tree of based on the deletion method and node importance by freeway efficiency based on shrinkage method combine with the degree of node, the close centrality, the node betweenness. So we develop two sets of samples including 4 variables.Finally, this paper combining the project request, comprehensively apply the theory and model we proposed, taking Henan Province, Anhui Province, Jiangsu province highway as the background. The results show that the method in this paper is consistent with the actual road network, and it can effectively analyze the structure of freeway network.