Study On The Influence Of Expressway Alignment Condition On Running Safety In Mountainous Area

In recent years,with the rapid development of expressway construction in our country,the problem of expressway traffic safety becomes more and more prominent.Among the many factors that lead to highway accidents in mountainous areas,the influence of linear factors is obvious.Compared with the plain expressway,Expressway in mountainous area has a small flat curve radius,a long continuous downhill section,poor combined alignment coordination and other characteristics,which often lead to serious traffic accident and many casualties.So,it is necessary to study on influence of expressway alignment on traffic safety and establish a kind of objective and reasonable evaluation index system and method to evaluate the influence of expressway alignment safety for improving preventing or controlling traffic accidents of mountain highway traffic accidents and improving traffic safety.Based on the natural conditions of mountainous areas and the overall characteristics of mountainous expressways and mountainous highways,this paper focuses on the unique linear features of mountainous expressways.Secondly,the influence of the linear factors of mountain expressway on traffic safety is analyzed from four aspects: plane line,longitudinal section line,cross section line shape and vertical combination line.Then,based on the relationship between the factors such as the plane line of the mountain road,the vertical line,the combined alignment with the traffic accident rate statistics,combined with the relevant standards and norms,the paper constructs the evaluation index system of linear safety impact of mountainous expressway The evaluation criteria of each index factor was put forward.At the same time,combined with the basic principles of the model,the evaluation criteria and evaluation criteria of the evaluation factors in the linear safety evaluation index system of the expressway in mountainous area are given.Then,based on the existing comprehensive evaluation methods,the improved AHP-FUZZY mountainous expressway linear safety impact assessment model was established.Among them,the combination weight of the index is determined by the improved AHP method and the entropy method,and the membership degree of the index is determined by the trapezoidal FUZZY distribution method.Finally,the case study of K130 + 501.71 to K146 + 777.55 of Chongqing Expressway is carried out.The results show that the model has good practicability.In this paper,the impact of mountain expressway on traffic safety is studied,and the influencing factors of linear safety of mountain expressway are analyzed emphatically.An objective and reasonable evaluation index system and theoretical method for linear safety impact of mountain expressway are established.The research results can scientifically guide the planning,design and construction of mountainous expressways(especially linear),and lay a certain theory and method for preventing or managing mountainous highway traffic accidents.