Service Level Evaluation Of Traffic Safety On Freeway

With China's rapid growth in freeway mileage, freeway network has been dramatically expanded. However, China's freeway has historically had a much higher accident rate and high mortality, which are too often disturbing the related administration. Based on this situation, there is urgent need for in-depth study of the freeway traffic accidents causes and its internal mechanism, and carrying out the research in freeway traffic forecast, which would be a necessary foundation for the establishment of freeway traffic safety service level classification system. The main content of this dissertation is summarized as follows:(1) The characteristics of China's freeway traffic accident was analyzed, and the causation mechanism of freeway traffic accident was described, and the influence of road conditions, weather conditions, traffic flow conditions, the driver and the vehicle conditions on freeway accident was analyzed. Research demonstrates that the road conditions, weather conditions and traffic flow conditions are the main factors affecting the freeway traffic accidents.(2) The negative binomial model was used in this study to describe the freeway traffic accident which represents the discrete and occasional characteristic. In the empirical study STATA software was used for regression analysis on a higher accident rate section of some freeway indicating that oversize vehicles mixed rate, curve ratio, average longitudinal slope, curvature, curved-slope combination and the special section are the most significant variables for the freeway traffic accident, and the coefficient of variables was estimated.(3) Based on the traffic accidents forecasting, the model for evaluating freeway traffic safety services level was brought up, and then the safety level was divided into 5 categories, one standard deviation distance for each other. The freeway traffic safety service level theory based on traffic accident rate was established.(4) In order to describe the freeway traffic safety service level more accurately and plausibly, a composite index system including both traffic accident rate and accident severity for the classification of freeway traffic safety service level was presented,and then the 5 grade classification for the distance of one standard deviation was brought up,stating that the reasonable model should be used in practical work.(5) The empirical research was implemented, taking a section of a freeway with a high level of accidents as an example, and the specific improvement measures were put forward. The final result of the improvement was re-evaluated, proving that the model had utilitarian values.