Rescue Route Optimization Under Urban Road Network Emergency Research

With the continuous expansion of China’s urban scale,urban environmental contradictions have become increasingly prominent,and various emergencies that cause great harm to people’s lives,production and safety of life and property have occurred from time to time.In this context,the establishment of a timely and effective emergency response system is of great significance in ensuring the safety of people’s lives and property.In this regard,scholars at home and abroad have done a lot of research on how to choose rescue routes according to the traffic conditions under emergencies.However,the existing path planning research in the prediction of road time weights under emergencies has not taken into account the law of congestion spread dissipation,and the existing model of congestion spread dissipation has not fully considered the impact of vehicle bypass.For this reason,relying on the sub-project of national key research and development project 8 "Safety guarantee technology of regional integrated transportation infrastructure",which is "Intelligent,networked emergency dispatching and evacuation rescue technology of cross-regional integrated transportation network under emergencies",this paper aims to provide information service for the travel routes of emergency rescue departments,and develops urban expressway under emergencies.In order to minimize the rescue travel time under emergencies,the dynamic network route selection and the prediction model of the expressway congestion spread are combined,and the rescue route selection method under the prediction of the expressway congestion spread dissipation law is proposed.Firstly,this paper analyses the characteristics of traffic flow parameters around the relationship model of traffic flow parameters,combining with the traffic flow data diagram of VISSIM traffic simulation output,and chooses Van Aerde model as the description object of urban expressway traffic flow parameters relationship model,which provides theoretical support for the establishment of Expressway congestion spread prediction model in the next step.Then,based on traffic wave model,from three aspects of road bottleneck capacity,road background traffic flow and ramp diversion and confluence,this paper quantitatively analyses the impact of bus proportion,road condition information,congestion distance,bypass density,speed difference between main and auxiliary roads and traffic flow on congestion scope under emergencies,and then puts forward vehicle bypass shadow.The prediction model of congestion spread under noise is tested by simulation traffic data,which lays a foundation for calculating the travel time weights of congested sections.Finally,based on the prediction model of congestion spread under unexpected events,the travel time of congested sections is calculated,and the influence of downstream congested vehicle Backflow on the travel time of sections is analyzed.The Dijkstra shortest path algorithm of "repeated optimization" under the condition of dynamic weights is designed,and the main sections are defined,so as to avoid the shortest path loss caused by important sections in the traditional algorithm.At the same time,a simulation experiment is designed to compare the path planning with the traditional path planning with the shortest distance,and to verify its effectiveness in reducing the rescue travel time.