Research On Vehicle Operation Characteristics At The Entrance And Exit Of High/Express Road Tunnel

Traffic safety at the entrance and exit of the tunnel is very important.Through the study of the operation characteristics of the entrance and exit of the tunnel,the changing law and influencing factors of the vehicle speed are analyzed,the operating speed model is established,a nd the law of the trajectory offset value of the vehicle is studied,It provides theoretical basis and key scientific evidence for revealing the accident occurrence mechanism of tunnel entrances,provides reference for the safety review and evaluation of highway and expressway tunnel sections and the prediction of cross-section speed,and provides data support for the design of tunnel sections,setting up traffic signs and markings of tunnel sections to regulate and restrict vehicle driving behavior,and improve the safety of tunnel sections.At present,the current domestic and foreign research on the operating characteristics of tunnel vehicles is mainly aimed at expressway tunnels.Foreign countries mainly focus on driving simulator simulation;domestically,they mainly focus on real vehicle driving and roadside data collection,but existing studies have a low sample size.(For example,the number of subjects is too small),the observation range is narrow(mainly from 100(or 200)meters in front of the tunnel to 100 meters behind the tunnel),and the limitation of the small amount of observation samples makes it difficult to accurately describe the speed of the driver at the entrance and exit of the tunnel.Selection behavior and vehicle operating state,especially the speed behavior and acceleration and deceleration characteristics of large vehicles.Firstly,it selects 6 tunnels on the urban expressways and highways in the SichuanChongqing area as the research objects,use radar speedometers,drone aerial photography equipment,wheeled rangefinders and other equipment to obtain vehicle speed,trajectory and other related data.And filtered and classifyied the acquired data,among them,34,581 are vehicle speed data,and 4,546 are trajectory data.To screen the acquired data,remove and classify abnormal data.The vehicles are divided into two types: cars and trucks,for analysis.It studies the speed characteristics and speed distribution laws of highway tunnels and expressway tunnel entrances and exits,and study the dispersion of vehicle speeds at the tunnel entrances and exits,study the influence of the horizontal and vertical lines of the tunnel on the speed.The results show that under the same cross section and vehicle speed,there is a strong dispersion between different vehicles.Drivers will accelerate when they leave the tunnel,but when there is a curve and intersection with a smaller radius in front of the tunnel exit,they will reduce their driving speed to adapt to the road conditions ahead.Secondly,according to the factors that affect the speed of the tunnel entrances and exits,established a vehicle running speed model at the entrance and exit of the tunnel,scientifically select the evaluation index,and verify the model.According to the deceleration/acceleration values between two adjacent sections,the acceleration values of cars and trucks in highway tunnels and expressway tunnels are calculated and analyzed.It can be concluded that the deceleration value of the vehicle is the maximum of 100 meters before the tunnel entrance to the tunnel entrance.The driver’s speed control behavior is studied,and analyze the driving comfort.Finally,the overall analysis of the vehicle trajectory offset value at the entrances and exits of highway tunnels and expressway tunnels is carried out,and the influence of different lanes,vehicle types and sections on the vehicle trajectory offset is studied.And study the lane-changing characteristics of vehicles at the entrance and exit of the tunnel.It studies the difference of vehicle trajectory offset under different vehicle speeds,and obtain the corresponding relationship through regression analysis.As the vehicle speed changes,the trajectory offset value of each vehicle type also changes at different rates.The lane-changing behavior of vehicles in front of the tunnel entrance mainly occurs near the boundary between the dashed line of the variable lane and the solid line of the immutable lane.Based on the key scientific and technological research projects of Chongqing Municipal Education Commission and the postgraduate scientific research and innovation projects of Chongqing Jiaotong University,this paper collects data such as vehicle speed and trajectory offset characteristics to analyze the operating characteristics and driving of vehicles at the entrance and exit of highway tunnels and expressway tunnels.Analyzed the driver’s driving behavior in order to reduce the occurrence of traffic accidents at the entrance and exit of the tunnel and improve the level of road traffic safety.