Research On Expressway Location Safety Evaluation Considering Traffic Impact Of Accident

The occurrence of urban traffic accidents will cause casualties and traffic congestion.Especially for the expressway that bears huge traffic demand,in the event of a traffic accident,it will cause indirect economic losses such as a large number of traffic delays.Based on this,considering the traffic impact of accident can improve the comprehensiveness and accuracy of expressway location safety assessment.The main research work of this paper includes the following:Firstly,the OBD data is statistically analyzed and preprocessed.The map matching algorithm based on map grid is used to complete the map matching of OBD data.The map matching can obtain the positioning point,positioning time,latitude and longitude,instantaneous speed and vehicle running direction.The average speed of the expressway is measured by location-time interpolation.Using the FCM clustering algorithm,the traffic state of the expressway is divided into six levels:very smooth,smooth,stable,relatively congested,congested and very congested..Secondly,based on Web text data the traffic accident attribute model was constructed,and the corresponding traffic accident attributes in the text data were extracted and processed according to the RDF of the accident attribute model.Combining the accident attribute of the test and traffic operation status,traffic impact attribute model of accident was built.And a traffic impact attribute recognition algorithm was designed to calculate the delay time and the number of lost vehicles caused by traffic accidents.An equivalent traffic accident quantity model based on traffic impact was establish and the corresponding calibration of this model parameters was complete as well.Thirdly,based on the number of equivalent accidents,the safety service level of the typical expressway location in Beijing was graded.Among the four-level safety service levels there were one of the two-ring locations in the city and three of the five-ring locations in the urban-rural junction.The influence of accident damage consequences and traffic impact on the classification of safety service level at Expressway location was analyzed.The damage consequences of traffic accidents had a great influence on the safety service level of the Expressway location in urban and rural areas,and the traffic impact of accident has a great influencet on the safety service level of the Expressway location in the city.Finally,the concept of traffic impact equivalent accident intensity was introduced.And an Expressway location safety evaluation method was proposed.The analysis results show that the safety service level is lower for the Expressway location where has the higher traffic impact equivalent accident intensity.And the larger traffic impacts equivalent accident intensity had the greater impact on the changing of location's safety service level.