Research On Identification Of Hazardous Road Sections Of Freeway Networks

In recent years,the rapid development of freeway in China has greatly improved the overall transport efficiency of road networks,optimized the transportation structure,promoted economic development and social progress.Although it brought us fast and convenient service,high accident rates and amazing property loss have been caused.The safety problem of freeway is still not optimistic,it is necessary to carry out research on it.Based on this,this paper carries out research on identification of hazardous road sections of freeway networks.Before carrying out the identification work,the road system should be divided into smaller road elements.In this paper,the definition of ‘homogeneous road section' is given,and the method of ‘clssification of freeway elements by natural node' is put forward according to the conditions of our country.After selecting the appropriate variables,the system cluster analysis method is used by SPSS software.The homogeneous sections are and the characteristics of them are analyzed.The differences between network safety management(NSM)and black spot management(BSM)are compared,and the significance of hazardous road sections is explicated.This paper introduces the concept,theoretical basis and implementation steps of freeway network safety management,and carries out the evaluation of expected accident cost based on homogeneous road sections.The average number of accidents and accident rate of each homogeneous section are calculated and the accidents are divided into three categories according to the severity.The average economic cost of fatal and serious injury,minor injury and only property loss accidents is figured out so that we can get three types of accident cost indicators.The proportion of three types of accidents on each section is also calculated so that we can get the weight of three types of accidents on each homogeneous road.The negative binomial regression model of each type of homogeneous sections is established,and the accident rate of each model is obtained.The expected accident rate of each homogeneous section is obtained by empirical Bayesian method.Multiplied by the weight of the three kinds of accidents,the expected accident rate of each class of homogeneous sectionis obtained.According to the accident cost indicators and the expected accident rate,the index called ‘comprehensive expected accident cost' is proposed.Based on the comparison on the methods and technical requirements identifying hazardous road sections between countries,the method on identification of hazardous road sections is proposed.Several hazardous road sections are identified in Liaoning Province Expressway Network using this method.The results showd that it is viable and practicable to apply the comprehensive expected accident cost in the study of freeway safety.This method enriches the theoretical system of freeway safety research and provides reference for the future improvement and prevence work.