Research On The Change Law Of The Driver's Visual Characteristics In The Highway Tunnel Group Section

With the development of highway network,the number of tunnels has been increasing year by year.As a special section of road traffic,highway tunnel groups have attracted wide attention because of its various forms of traffic safety problems.It is necessary to carry out research on the change law of drivers' visual characteristics because the driver is the most important influencing factor of accidents.Aiming at the characteristics of multi-tunnel in tunnel group sections,this paper analyzed the differences in drivers' visual characteristics in corresponding tunnel group sections.This paper proposed a visual stability model for drivers in tunnel group sections and verified its reliability by heart rate index.In this paper,the highway tunnel group has been redefined as a continuous tunnel consisting of two or more tunnels with the length of connection section less than 650 m.The single tunnel group has been divided into the entrance section,the middle section and the exit section.And the section between the two tunnels has been defined as the open section.The indexes of eye movement and heart rate have been proposed.According to the characteristics of multi-tunnel in tunnel group,the differences of drivers' visual characteristics in corresponding sections have been analyzed from four aspects including fixation time.The significance test has been carried out.Based on the division of drivers' fixation region,the probability distribution of drivers' one-step transfer fixation and the stationary probability distribution of fixation in the corresponding sections have been obtained.The differences have been compared and analyzed.According to the difference of drivers' visual characteristics in tunnel group,several engineering improvement suggestions have been put forward.Based on the difference of drivers' visual characteristics in the corresponding sections,7 evaluation indexes have been selected.Based on principal component analysis,the driver visual stability evaluation model has been proposed and the formula of evaluation score E has been obtained.E=0.377 has been proposed as the visual stability evaluation threshold by using 85% position.The reliability of the evaluation model has been verified by SDNN.The evaluation results were basically consistent with the results reflected by SDNN.The variation law of visual characteristics in highway tunnel group has certain practical value.It can provide scientific basis for highway management and maintenance.The proposed visual stability evaluation method can be used to evaluate road safety in highway tunnel groups and can also be used in advanced driving assistance system.By evaluating the driver's visual stability,the driver's degree of control over the vehicle can be judged.Then the system can decide whether to intervene and assist the driver.It can be further expanded to other kinds of road research in the future.