The Research Of Road Network Vulnerability Based On Generalized User Equilibrium

The research about road network vulnerability have promoted the development of theory of traffic network,it is necessary to use the model,data and decision support tools for accurate assessment and reducing the vulnerability of the road network.At the same time,the assessment of road network vulnerability is helpful to determine the key infrastructure in the road network,which can provide decision-making basis for road management department to take emergency measures and preventing management measures to achieve the purpose of improving the service level of road network and the ability of emergency prevention.In this paper,The road network vulnerability is defined as the property of the decline of road network performance due to the lose of the partial or whole connectivity capacity when the elements of road network are affected by random disturbance events.Firstly,the influencing factors of road network are analyzed,which can be divided into two categories,namely internal factor and external factors.The former include topological structure of road network and the road capacity,the latter include the natural and human factors.Secondly,Cumulative Prospect Theory is used to build the generalized user equilibrium model,which explicitly considering the limited rationality of travelers’ route choice behavior and the fluctuation of travel demand.and the MSA algorithm is designed to solve the model,which is taken as the method to assign the traffic flow in the assessment of road network vulnerability.Then,the state and the structure characteristics of road network are considered into the vulnerability evaluation,and the evaluation indexes of link importance degree are defined from four aspects,including the accessibility,network efficiency,average prospect value and the ratio of failure paths from travel time and generalized travel cost two aspects.these indexes can be used to measure the influence degree on the road network performance after the failure of link.And the relative weight of each importance index can be determined by the method of analytic hierarchy process,based on which,the vulnerability index of link is constructed.And the key links in the network can be identified according to the rank of vulnerability evaluation index via the failure of link one by one,and corresponding evaluation process is also given.At last,network vulnerability assessment is carried by using the test network,and the analysis of main parameters in is also carried.The results have shown that travelers’ route choice behavior,congestion degree and the fluctuation of demand will have an important influence on the assessment of road network and identification of key links.Different demand level,demand fluctuation and assumption of route choice behavior will lead to different network vulnerability assessment results.