Safety Assessment And Improvement At The Entrance And Exit Of Expressway Tunnel

In past years, with the rapid development of economy highway construction experience a prosperity especially in western China. Limited by the special terrain, long tunnels become more and more among mountains result in tunnel group. However, on the road segment of entrance and exit of tunnel grouptraffic accident rate is high always significantly high severity of injuries. In order to ensure the safety oftransportation in this region, communications departments spare no effort to improve the traffic safety environment. Therefore, how to evaluate the status of entrance and exit of tunnel group and find the factors affect safety is significantly important.This paper builds a database based on the statistic of traffic accidents occurring at the entrance and exit. From the core issues of transportation safety, the author uses the theory of statistics to establish a evaluate modelto analyze the safety problems and propose measures to promote the safety. The main content of this paper is summarized as follows:(1)Based on the database and methods of statistics summarize the concept of tunnel group and to analyze the Spatial-Temporal characteristics, severity level and type of traffic accident at entrance and exit of tunnel group.(2)Analyze the factors affect transportation safety and reveal the reasons of traffic accidents from drivers, road segments and driving environment to build a logit model. The effect of each factor can be calculated based on the model so factors can be ranked.(3)Analytic Hierarchy Process(AHP) has been well developed and widely applied but there are many doubts on the measurement in making comparison matrix. To deal with this problem fuzzy membership function is introduced. Combine the AHP and normal distribution fuzzy sets a new model is built to produce the fuzzy sets of safety coefficient. Also, the accuracy of the model is verified by example.(4)According to the analyses above, some measures including alignment design, facilities to protect driver’s visual characteristics and GPS technologies are mentioned to improve the condition at entrance and exit of tunnel group.