Research On Traffic Characteristics And Security Assurance Technologies Of Tunnel Intensive Section In Mountainous Expressway

With the rapid development of expressway in our country,the mountainous expressway is increasing gradually.Due to geographical conditions and terrain constraints,a large number of expressways across the valley and through the mountain,more and more tunnels appear,so as to tunnel intensive section is formed.Tunnel intensive section is a high incidence area of traffic accident,fire and other emergencies,so the tunnel intensive section becomes the focus of safety protection in mountainous expressway.At present,security technologies for tunnel intensive section have not been systematically studied,mostly for single tunnel.The current research results can not meet the traffic safety requirements of tunnel intensive section in mountainous expressway.Therefore,it is necessary to further study the traffic characteristics and security technologies of tunnel intensive section in mountainous expressway.The traffic environment characteristics of tunnel intensive section were analyzed from four aspects of light-dark adaptation in tunnels,noise,air quality and the vehicle operational characteristics.Experimental scheme of radar positioning and velocity measurement was made.Combined with the traffic surveillance video data,the distribution characteristic of each data acquisition point was researched from three aspects of traffic volume,speed and time headway.By comprehensive comparison,the traffic flow characteristics of data acquisition points were analyzed to provide a theoretical basis for the research of speed limititation and other security technologies in tunnel intensive section.From four aspects of people,vehicles,road and tunnel environment,this paper analyzed the influence on the traffic accidents of tunnel intensive section in mountainous expressway.According to the traffic accident statistical data of tunnel intensive section in mountainous expressway,the traffic accidents distribution characteristics of time,space,climatic and vehicle type were studied by statistical analysis,chart analysis and other methods.Combined with the main influence factors of traffic accident,the main causes of traffic accidents in tunnel intensive section were determined by principal component analysis.Making illumination acquisition scheme of tunnel intensive section,different experimental positions’ illuminances were obtained using illuminance meter and other equipments.Change rugulations of illumination with location were analyzed and model between illuminations of tunnels of different lengths and distances from the tunnel entrance was established.Based on the collected data in the tunnel,the relationship between the illumination of different time and the distance from the tunnel was established.According to the study of physiological basis of driver’s vision system,an experimental program was developed to determine the driver’s response time.The driver visual reference system characteristic simulation scheme was designed,and the simulation principle,simulation conditions and simulation process were defined.Based on the simulation results of reference systems,the effects of different reference system transition facilities in tunnel entrance on drivers’ heart rate,the perception speed,the running speed and the lateral position were gained.Based on the types of traffic safety facilities of tunnel intensive section in mountainous expressway,the system framework of safety facilities was established.On account of the safety level of tunnel,a set of traffic safety facilities for a single tunnel was set up,and a set of traffic safety facilities was set up according to the different sections of tunnel intensive section.High frequency,intermediate frequency and low frequency tunnel entrance reference systems were established,and the set size and position parameters of each reference system were studied,and light transition technologies such as tunnel intelligent dimming facility and shading facilities were put forward.The model of tunnel entrance sign was established,at the same time,geometric indicators of speed limit signs and markings were determined.Based on visibility,longitudinal slope of the road and road surface adhesion coefficient,the speed limit model of the bad weather was established,and speed limit values in different weather conditions were determined.The variable speed limit theory was put forward,and the calculation model of the longitudinal position of each variable speed limit sign was established.The research results of this paper are of theoretical value and practical significance for improving China’s security technologies of tunnel intensive section in mountainous expressway and enhancing the safety of tunnel intensive section,and provide technical support for the safe operation of mountainous expressway in China.