Research On Traffic Accidents Causes & Occurrence Mechanism On Urban Snow And Ice Road

The snow and ice condition area in our country is approximately half of the national land area, especially the cities belongs to Northeast and Northwest area whose road traffic is easily affected by the snow or freezing. According to statistics, the number of traffic accidents caused by the snow and ice is generally higher than 3~4 times in the normal condition, so the urban snow and ice road traffic safety is stern in our country. Through the investigation and analysis of to urban snow and ice road traffic accidents, we find that the accident's occurrence is affected by many correlation factors except the reduction of road friction coefficient. Therefore, the research on traffic accidents causes & occurrence mechanism on urban now and ice road has the vital significance to the road traffic safety improvement.The snow and ice on the road will have the influence on the urban road traffic system, the most obvious influence are road surface characteristics, the traffic operation characteristics and the operation environment, secondly it is the transportation participants, and the finally is the vehicles braking and handling stability characteristics. Based on the experiment principle of traffic engineering, statistics and the psychology and from the urban road traffic system's constitution of person, the vehicle and the road, the paper designs the snow and ice road surface friction coefficient testing experiment, the driver characteristic experiment and the car braking experiment separately, then the influence of snow and ice condition on the urban road traffic characteristics is studied by using the method of combining quantitative analysis with qualitative analysis.Considering the traffic accident's characteristics happened on the urban snow and ice road, the influencing factor of urban snow and ice road traffic accident will be considered and screened, so we can definite the causes constitution of urban snow and ice road traffic accident, the maximum difference method is introduced to calculate the accident causes'importance. In view of the superiority of bayesian network in the systematized analysis and with the accident information, the bayesian network model used to analyze the urban snow and ice road traffic accident causes is constructed; it can analyze the accident causes occurred on snow and ice road.Constructing the elements' logical relation of urban snow and ice road traffic system, the concepts of the urban snow and ice road traffic accident occurrence mechanism is analyzed and the relationship between accident causes and occurrence mechanism will be analyzed in detail. According to the difference of road traffic accident's causes and the occurrence mechanism, the paper studied the occurrence mechanism of system or factor function missing accident and put the road traffic accident occurrence mechanism into three kinds, then the causation process of each kind accidents was constructed. Considering the person, the vehicle, the road and the environment's state change in the traffic accident developing process, the paper also proposes time-condition method using to analyze road traffic accident occurrence mechanism.Using the maximum difference method and time-condition law to carry on the analysis of the urban snow and ice road traffic accident cases, and compares with the actual situation to improve its deficiency, the analysis result indicated that these two methods are simple and practical, they can applied in the actual accident handling work.