Research On Traffic Safety Guarantee Technology For Long Downhill Tunnels In Mountainous Highways

With the further development of highway construction to mountainous areas in China,the proportion of tunnels in highways is increasing,and the combined sections of long tunnels and continuous downhills appear frequently,forming a large number of long downhill tunnels.Traffic accident reports in recent years show that road traffic accidents in long downhill tunnels are becoming more frequent,which make long downhill tunnels become the dangerous bottleneck of highways,resulting in increasing economic losses.The traffic safety of long downhill tunnels in mountainous highways is receiving more and more attention.Therefore,it’s necessary to study the traffic safety facilities for the combination of continuous downhill and long tunnels in mountainous highways by analyzing traffic safety influence factors and accidents of long downhill tunnels in mountainous highways to ensure the driving safety,which is also significant for improving the level of highway management and the design of highways.Based on the analysis of accident data and road design data of long downhill tunnels in mountainous highways,the main causes of accidents are studied through statistical analysis of the accident distribution characteristics and traffic safety influence factors of long downhill tunnels.It is concluded that driver’s visual influence factors and traffic facility factors are two major factors,and the main research contents are identified as traffic safety facilities and speed management technology based on visual information induction.In terms of traffic safety facility research,the guardrail facilities and sight guidance facilities of long downhill tunnels are improved and optimized,through theoretical research and investigation of current situation.In terms of speed management technology,the basis for speed management of long downhill tunnels in mountainous highways is determined according to the impact of vehicle speed and speed limit on traffic safety,that is,controlling the vehicle speed and reducing the dispersion of vehicle speed.According to the principles of visual psychology,the design parameters of reverse perspective visual illusion deceleration marking and tunnel visual intervention deceleration facilities are proposed,and the specific impacts of different forms,angles,colors of marking or reflective facilities on driving behavior are studied through comparative experiments.Lastly,the Yunmengshan tunnel No.1(to Shijiazhuang)in the Baoding section of the Zhangshi Expressway is chosen based on the current situation of the road and accident data,for the empirical research on traffic safety guarantee technology.Traffic safety measures are set up in five parts of the tunnel: the concrete guardrail section,the tunnel entrance section,the middle of the tunnel,the tunnel exit section and the curve section outside the tunnel.The scheme of traffic safety guarantee for the tunnel is formulated,and the expected effect of the scheme gets effective evaluations.The research results show that the reverse perspective visual illusion deceleration marking and tunnel visual intervention deceleration facilities for long downhill tunnels in mountainous highways are effective in reducing the average speed of vehicles and the dispersion of vehicle speed,which will improve the traffic safety of the tunnel.The application of traffic safety measures on the Yunmengshan tunnel No.1(to Shijiazhuang)proves that the traffic safety guarantee technology for long downhill tunnels in mountainous highways has good applicability and operability.