Research On The Driving Suitability Of The Export Section Of The Mountainous City Tunnel

With the accelerating of China's urbanization and the rapid development of city transportation,city tunnels are widely used as an important way to ease traffic,reduce land use and shorten the mileage,especially for mountainous city,city tunnel has become an important part of the road traffic.Because of the particularity of the tunnel environment and the complexity of the road conditions and traffic conditions,when the driver is out of the tunnel,the psychological load will suddenly increase and influencing the driving suitability,so the tunnel exit section becomes the bottleneck of the potential high accident rate and the high degree of harm.Therefore,it is of great significance to improve the tunnel design and improve the safety of the tunnel to study the driving suitability theory of the exit section of the mountainous city tunnel from the visual characteristics of the driver.First of all,through the investigation and observation of city tunnels in Chongqing,this paper analyzed the environment and traffic characteristics of the exit section of mountainous city tunnel.Based on the analysis of driver's visual and psychological characteristics,the eye movement test of tunnel exit section was designed.Secondly,selecting city tunnel in Chongqing as the research object,this paper use Smart Eye Pro5.7 non-invasive eye tracker to carry out the real vehicle test of the tunnel section and the general section,and collecting eye movement data of each section,and using hand-held GIS to record the linear parameters of the tunnel exit section.The visual characteristics of drivers were observed by gaze,saccade,blink and pupil diameter.The changes of visual indicators of each section were analyzed,the PERCLOS method was used to evaluate the level of the driver's alertness,and the critical value of the tunnel exit radius is 700 m.According to the change of the driver's eye movement parameters,combined with the characteristics of the tunnel environment,the length of the transition section of the tunnel exit is determined to be 120 m in the tunnel to the 160 m outside the tunnel.Then,in order to establish the evaluation model of driving suitability,introducing the reliability theory and combined with the driver's eye movement characteristics,this paper put forward the driver's visual characteristics index and reliability index,and the driving accuracy index of driving suitability was obtained,suitability level is divided into 5 levels.Through the fitting of the two indexes,the evaluation model of driving suitability was obtained,and the classification method of suitability degree of tunnel exit section was put forward.Finally,based on driving suitability evaluation model,the paper put forward some suggestions for improving the safety of the exit section of mountainous city tunnel from safety design of horizontal curve radius,lighting of exit section and visual environment.This paper put forward the analysis and evaluation method of the driver's visual characteristics and driving suitability of the tunnel exit section of the mountainous city,the obtained rules and models provide a theoretical basis for optimal design of tunnel exit.It has a certain value and significance to improve the safety and efficiency of the tunnel exit and improve the driving comfort.