Study On Driving Safety Of Mountainous Highway Tunnel Group Based On Driver’s Visual Load

With the rapid development of Southwest China,the highway is gradually developing to the mountains and hilly areas.According to relevant data,China has become the country with the largest number of tunnels,the most complex types and the fastest development in the word.As a special connection section of road traffic in China,the traffic safety problems of mountain highway tunnel group sections are complex and diverse,which has attracted wide attention.The tunnels in mountainous highway tunnel group are dense,and the spacing between tunnels is short.In the driving process of drivers,the entrance and exit of tunnels occur frequently,which makes the driving light environment change frequently,causing a large load on the visual function of drivers and increasing the risk of driving safely.This paper is based on the Science and Technology Research Project of Chongqing Education Commission(KJQN201900722)and the Open Fund of Chongqing Key Laboratory for Coordination and Safety of ‘People-Vehicle-Road’System on Mountainous Complex Roads(2018HVRC05).Through the combination of real vehicle test,‘scaled model’ experiment and software simulation experiment,the driver’s eye movement behavior is selected as a parameter to analyze the change law of the driver’s visual load in this special section and explore the driver’s visual load model of mountain highway tunnel group section.In this paper,based on the investigation of the environmental characteristics of mountain highway tunnel group,combined with the driver’s visual adaptation law,the mountain highway tunnel group is redefined: including two or more tunnels,and the tunnel spacing is less than 500 m continuous tunnel.Due to the frequent mutation of light environment in tunnel group,the driver experiences continuous and repeated ’ black and white hole effect ’ in tunnel group section,which seriously affects the driver ’ s perception process of information and causes short-term visual ’ blank ’,which is easy to cause traffic accidents.Then,by analyzing the driver’s basic eye movement characteristics,it is found that the mountainous highway tunnel section has an impact on the driver’s visual load.Through the dynamic clustering of the driver’s gaze point coordinates,the driver’s visual interest area in the mountainous highway tunnel section is divided into seven categories.The distribution proportion of the driver’s gaze point in different interest areas is counted.The Markov chain model is used to calculate the one-step transfer probability and the stationary distribution probability of the driver’s different gaze areas,and to study the driver’s attention spatial distribution and fixation transfer characteristics in the tunnel group environment.Finally,on the basis of analyzing the change trend of driver’s pupil area,the maximum transient velocity value of pupil area is selected as the basis of driver’s visual load.Taking tunnel length,tunnel spacing,driving speed and tunnel environmental illumination as parameters,the relationship between each parameter is analyzed by using trend surface model and curve estimation method,and the driver’s visual load evaluation model of mountainous highway tunnel group is proposed.The results show that the visual load of the driver in the mountainous highway tunnel group section decreases with the increase of the length of the tunnel group connection section.When the first tunnel length of the tunnel group is 560 m,the visual load of the driver in the tunnel group connection section is the smallest.In the adjacent tunnel group connection section,the driver ’ s speed is positively correlated with the visual load.In the connection section of the continuous tunnel group,the driver ’ s speed is negatively correlated with the visual load.In the exit section of the tunnel group,when the last tunnel length of the tunnel group is 1500 m,the driver ’s visual load is the smallest,and is negatively correlated with the length of the tunnel group connection section.When the lighting level at the tunnel entrance is 117 % of the standard value,the driver ’s visual load is the smallest.When the lighting level of the tunnel exit section is 121 % of the standard value,the driver ’s visual load is the smallest.