Research On Road Safety Guarantee Level For Mountainous Highway

Currently, the mortality rate and injury rate of mountainous highway traffic accident(MHTA) are much higher than plain highway, and serious traffic accident occurs frequently in mountainous highway. Traffic safety issue of mountainous highway in China is protuberant. Road condition and traffic environment have a significant effect on traffic safety, and they can act on drivers or vehicles directly and indirectly, causing traffic accidents. Road condition and traffic environment are the objective hardware conditions of road traffic system(RTS), and they are not only the basic conditions of RTS, but also the basic safety guarantees for traffic operation. So the objective traffic safety guarantee degree or level that road condition and traffic environment provide for driving is defined as road safety guarantee level(RSGL) in this paper. Therefore, it is very important for improving the safety of mountainous highway traffic system(MHTS) to improve the safety guarantee level of road condition and traffic environment(that is RSGL). Thus, it is extremely urgent for preventing or governing MHTA and improving the safety of MHTS to research on RSGL for mountainous highway and to establish an objective and reasonable evaluation method of RSGL for mountainous highway.Firsty, the concept and classification of mountainous highway were elaborated, and the characteristics of MHTA were summarized. The characteristics of MHTS were analyzed from driver’s psychology and physiology, vehicle on being driving, road condition and traffic environment. The basic principle of safety driving for vehicles in mountainous highway was put forward based on the analysis of its stress and driving stability when a vehicle is driving on mountainous highway. Secondly, the concept of RSGL was put forward in view of the properties of four elements of road traffic system, and the differences between RSGL and two similar concepts were elaborated. The influence that road alignment, pavement condition, traffic safety facility and traffic environment have on RSGL for mountainous highway were analyzed. A general evaluation model of RSGL for mountainous highway was built according to the analysis of the definition and the influence factors of RSGL, and an occurrence mechanism of MHTA based on RSGL was put forward according to the analysis of the influence ways that RSGL have on the safety of MHTS. Then, the evaluation index system and the grade intervals of every index factor for evaluating RSGL for mountainous highway were built, and the assignment method and the rank interval partition standard of each index factor were put forward based on the researches of existing relevant norms or standards and mountainous highway safety theories. An evaluation model of RSGL for mountainous highway was set up by applying the improved matter-element extension model, and the grade standards and the evaluation processes or steps of RSGL for mountainous highway section were provided. In the proposed model, classical field, matter-element waiting to be evaluated, weight determination method and maximum membership degree principle in the traditional matter-element extension theory were improved. These improvement measures include(1) presenting a normaliaztion to deal with classical field and matter-element waiting to be evaluated;(2) determining the weights of all rating indices with variable weight theory;(3) substituting closeness criterion for maximum membership degree principle;(4) grading evaluation object with the characteristic value of class variable. Finally, case study shows that the proposed model is consistent with actual situation. Sensitivity analysis show that RSGL of Guangqian road section is more easily affected by maximum longitudinal slope, horizontal and vertical linear combination design index, traffic sign and marking design index, safety barrier design index and traffic saturation.RSGL for mountainous highway is the research object of this dissertation. An occurrence mechanism of MHTA was put forward from a novel angle, and an evaluation model of RSGL for mountainous highway was built. The problem about the relationship between RSGL and the safety of MHTS was answered scientifically. Research results can scientifically guide the planning, design and construction of road engineering and traffic engineering for mountainous highway, and they can provide a certain theory and method for the prevention or treatment of MHTA.