Research On Macroscopic And Microscopic Comprehensive Methods For Evaluating The Traffic Safety Of First-class Highways

Traffic accidents are external reflections to the internal operating chaos of the traffic system.Studying the causes of traffic accidents and analyzing the accident inducements and mechanisms are the keys to improve the traffic safety internally from the traffic system.In fact,road environmental factor is a very important cause that should never be ignored in traffic accidents.In China,road traffic safety problems were severe,and traffic accidents occurred frequently,thus giving rise to massive losses to the people and the state.Traffic safety problems on the first-class highways were especially serious;the first-class highway only occupied 1.75% of the total mileage of the road network,but its accident mortality was the highest,up to 8.79 persons per 100 km.Concerning about this situation,the safety conditions of the first-class highway are urgently improved in China.Road traffic safety evaluation is a premise and basis for improving the traffic safety.This thesis conducted the study in turn of the analysis on the characteristics of traffic accidents,the establishment of evaluation model,the optimization of data collection method,the grade classification of safety condition as well as the model validation and so on.In this thesis,the foreign and domestic methods for evaluating road traffic safety were first analyzed and reviewed,and then divided into macroscopic and microscopic evaluation methods according to the study objects.As a result,the shortcomings and limitations of these methods in the actual application were summarized.The traffic characteristics and accident characteristics of the first-class highway were analyzed;the traffic safety of the first-class highway was divided macroscopically and microscopically by mapping the actual roads based on the basic concept of graph theory,for clearly defining the evaluation levels and scope.Then,macroscopic and microscopic traffic safety evaluation index systems were respectively established through qualitative and quantitative analyses on the affecting factors of traffic safety.A primary index model for the traffic safety evaluation of the first-class highway was established according to the evaluation index system.Then,a gray comprehensive evaluation method based on the combination weight of entropy weight and order relation analysis weight was established by synthesizing entropy theory and related gray evaluation theories;the traffic safety level corresponding to each evaluated object was determined by calculating the whiten function matrix and synthesizing gray clustering coefficients.The parameters of this model were determined using multiple weight granting methods.The data acquisition method demanded by the traffic safety evaluation model of the first-class highway was established based on the principles of objectivity,operability,consistency,and practicability,and then the practical application of the data acquisition method was summarized and optimized.The macroscopic and microscopic traffic safety conditions of the first-class highway were divided into five levels according to the gray category distribution of the gray clustering evaluation model,and also the related safety levels were qualitatively described.The rationality of the comprehensive traffic safety evaluation model was verified using subjective validation method,safety index verification method,and accident data verification method.The result showed that the safety levels of the evaluation model based on the gray clustering of comprehensive weight were consistent with those of the traditional evaluation method,and could reflect the actual road safety condition.