Research On Evolution Mechanism Of Traffic Accidents On Ice-snow Covered Urban Expressway

At present,the traffic safety situation is grim.With the improvement of motorization degree and the increase of car ownership,more than 1.3 million people died in road traffic accidents in the world every year,which caused great damage to people's property and life.So it is extremely important to analyze the causes and evolution mechanism of the accidents.In recent years,expressway has developed rapidly and become an important part of road traffic system in some cities,which effectively alleviated the urban traffic pressure and improved the residents' travel environment.At the same time,because the expressway uses full-enclosed or semi-enclosed viaduct in the urban,which can be continuously passaged with no traffic lights and make people travel more convenient.So vehicle's speed is faster on the urban expressway than it on the other city road,the consequences of traffic accidents tend to be more severe,which brings about an upward trend in the proportion of accidents year by year.In the Northeast of China,snow is seriously covered on the road in winter in the condition of snow and ice weather with low temperature,which has greater impact on the urban expressway and seriously hinders its capacity.It often causes traffic accidents such as scratch,rear-end and collision of fixation and so on.For this reason,research on traffic accidents happened on ice-snow covered urban expressway is carried out from the perspective of the formation reasons and evolution mechanism of traffic accidents,which can effectively improve the road traffic safety situation and improve the safety level.Firstly,traffic accidents on ice-snow covered urban expressway are taken as the research object,and it is analyzed that the influence of the elements on traffic accidents on ice-snow road from four aspects: people,vehicles,roads and environment.Based on the probabilistic reasoning and graphical features of the Bayesian Network in the system analysis,according to the reality of the traffic accidents statistics,accident cause analysis model using Bayesian Network is developed and the cause of traffic accidents and diagnostic reasoning are analyzed.As a result,it shows that the weather conditions and road sections have the greatest impact on traffic accidents happened on ice-snow covered urban expressway.Secondly,the evolution mechanism of traffic accidents happened on ice-snow covered urban expressway is expounded,and it is discussed the relationship between the causes of traffic accidents and the evolution mechanism.Based on the relationship with each influence factor,a method of time-state analysis is used to analyze traffic accidents happened on ice-snow covered urban expressway especially at straight road,weaving section and other positions.Relationships of people,vehicles,roads and environment is studied during the development process of accident in different period of time,and the overall development process and the internal changing law of traffic accidents is grasped to provide a theoretical basis preventing such accidents.Finally,on the basis of theoretical research,it is analyzed several cases of traffic accidents happened on ice-snow covered urban expressway.The Bayesian Network is used for reasoning and analyzing to find the accident probability under the cause of formation.The time-state analysis method is used to get the evolution process of the accident.The results show that the main reason for the accidents lies in the driver's factors,mainly including the illegally driving and improper operation of the drivers.Other reasons are included: bad road conditions,bad weather conditions and pedestrian who across the street rashly and so on,which have some influence to traffic accidents.