An Integrative Vulnerability Evaluation Model To Urban Road Network Based On Complex Network Theory

In recent years, further research on the complex network theory has provided a newdirection of transport network analysis and research for scholars at this field. Since urbanroad network is the important carrier of urban traffic activities, quantitative evaluation ofthe network·s vulnerability is becoming a research focus nowadays. Based on thecomplex network theory and the existing conceptions, the definition of the urban roadnetwork vulnerability is proposed in this paper. Vulnerability of urban road network is asusceptibility to incidents which can trigger considerable reductions to road networkserviceability, without considering failure probability of the network unit.Firstly, the definitions of urban road network running state vulnerability andstructural vulnerability are proposed in this paper, and the evaluation indices are givenrespectively. The internal relationship of the running state vulnerability and the structuralvulnerability is illustrated from the perspective of urban road network topology structureand traffic demand characteristics, in order to show the necessity and reasonableness ofthe urban road network vulnerability evaluation. Secondly, the structure-running stateindex of urban road network is put forward to identify the network vulnerability source.The Original Method is used to build the topology of urban road network, and the trafficflow is distributed based on the User Equilibrium Assignment Model. Thirdly, Withstatic vulnerability assessment principle, the structural vulnerability indices arecalculated without considering the cascading failure; with dynamic vulnerabilityassessment principle, the running state vulnerability indices are calculated consideringthe propagation effects of traffic congestion. Last but not least, the integrativevulnerability evaluation model of urban road network is proposed based on the principalcomponent analysis method.In the instance analysis section, the road network of a city is loaded with twodifferent traffic demand, and the results show that the vulnerability of road network is influenced by two factors, network topology structure and network running state.The integrative vulnerability evaluation model proposed in this paper overcomes thedeficiency of the assessment from a single perspective. The model combines thestructural and running state characteristics of the urban road network effectively, and theassessment of the urban road network integrative vulnerability has been realized. Theresults of the evaluation show that the model can identify the vulnerable unit of the roadnetwork precisely, and can provide some scientific basis for urban traffic managementand planning.