Study On Accident Impact Situation Cluster Analysis And Early Warning Measures Of Freeway

The occurrence of traffic accidents showed diversity and complexity,especially on freeways.Sudden traffic accidents reduced road capacity,causing delays in travel and increased travel time.To a certain extent,they also became a constraint on the development of China's national economy "bottleneck".Therefore,it is necessary to predict the impact of the occurrence of accidents on the operation of the freeway,so that targeted early warning measures can be taken to ensure the passage efficiency and operational safety of the freeway during the accident.Firstly,the thesis analyzes the characteristics of accidents and their impacts on freeways,and proposes the concept of accident impact scenarios.From the perspective of accident attributes,traffic attributes,and external environmental attributes,it identifies the factors affecting the accident,and builds an accident impact scenario clustering index system design at speed of 100km/h.Secondly,based on the matter-element extension model,clustering studies are made on accident impact scenarios.Considering the large number of highway accidents and the fact that accident data is difficult to obtain,this paper selects the middle value of each indicator's classification threshold and arranges and groups them.Each type of combination has a certain degree of representativeness.The eigenvalues of the level variables under various combinations are calculated,and the accident scenarios belonging to the same level of the eigenvalues of the level variables are clustered,and a total of four possible accident impact scenarios are obtained.Thirdly,according to the division of the affected areas of freeway accidents,the corresponding early-warning response measures are given from the point of view of speed limit and traffic limitation and the traffic organization after the accident for each type of accident impact scenario.An example analysis of the response measures under the four accident scenarios of two-way six-lane freeway was carried out.Finally,taking Huangyan Freeway as an example,the accident impact scenario of a high-speed case accident was determined and the effectiveness of the corresponding early warning measures under the accident impact scenario was verified by vissim simulation to verify the reliability of the research theory.