Research On Partition Of Traffic Accident Influence Degree Based On Evolution Of Cascading Failure

With the rapidly development of urban transportation,the contradictions of demand and supply lead to serious traffic accident,which become one of the key issue to the national economic development.Traffic accident not only causes security problem,also brings huge destruction on the stability of traffic system.In order to reduce traffic problem which caused by traffic accident,it is necessary to carry out more deep research from the perspective of system and combine the knowledge of cross-disciplinary.Traffic system is regards as a huge,typical and open complex system,it has become a hot topic at home and abroad.Using the complex theory to study the urban traffic problem,not only including the complex of road network,due to the driving characteristic of randomness and irrational on the network,the evolution of network is more complex.Traffic accident can be regarded as one road a certain direction on road network lost the capacity of transport.Therefore,subsequent vehicles have to find another alternative path to complete the trip.In this process,the alternative road can not bear extra vehicle and lead to chain reaction.This phenomenon is called cascading failure in complex network theory.Based on the cascading failure,the route choice behavior when facing the accident is researched.The cascading failure model is redevelopment combined with network traffic flow loading.Then,in order to distinguish the degree of all the road on the network,the concept of density entropy of traffic flow is proposed.The partition of traffic accident influence degree is completed by using cluster analysis,Specifically,the main research work in the thesis are as followings:To address the load distribution problem in the process of cascading failure,the route choice behavior when facing traffic accident is considered.The network flow loading using prospect theory is combined with complex network theory.Duo to the delaying of network loading,the delay load and the duration of accident are further considered in the process of cascading failure.And the simulation steps are given.The process of cascading failure can give the failure road caused by the traffic accident,but can not quantified the serious degree of the impact for each road.Therefore,the construction method of density entropy of road is proposed.And combine it with cascading failure,the degree of impact for each road caused by accident road is given for the prospective of time.Based on that,the partition of traffic accident influence degree model was established based on clustering analysis.Finally,the model is applied and analyzed.The space-time affect areas of different accident road is explored,the optimal number of partition and the road number exist in the partition are given.Using the zero flow time and initial flow volume as initial parameter,the relationship between initial parameter and the partition of traffic accident is researched.And the effect of physical location of accident road on the partition of influence is analyzed.