| Due to the closed space,low illumination,no scenery and distinct changes in color in the middle section of the extra-long tunnel,the driver ’s attention is mainly concentrated in the front of the road,which is easy to produce fatigue and depression in a short period of time,resulting in a decrease in the driver’s driving performance.This phenomenon is a typical ‘short-term fatigue’ phenomenon.Drivers with short-term fatigue are prone to adverse driving behaviors such as speeding,which brings great risks to driving.At present,the measures to solve the problem of ‘short-term fatigue’ of drivers in extra-long tunnels at home and abroad are to set up related facilities such as painted natural landscapes,colored patterns and colored light strips in a certain section of the tunnel.Most of the settings are based on the engineering experience of designers,and the relevant specifications do not give the exact theoretical basis and unified setting method.Some settings of key parameters lack comprehensive and systematic theoretical,methodological and technical support.In order to solve the problem of driving safety risk caused by driver fatigue in extra-long tunnels,it is urgent and practical to study the mechanism of fatigue wake-up zone and the setting of key parameters in extra-long tunnels.In this thesis,the super-long tunnels and super-long tunnel groups in mountainous areas are taken as the research objects.Combined with traffic engineering,road traffic safety engineering,human factor engineering and other disciplines,through natural driving test,theoretical calculation of key parameters and indoor simulation dynamic test,the key parameters of fatigue wake-up area of super-long tunnels are solved and verified by combining qualitative and quantitative,real vehicle and simulation.The main research contents and conclusions of this thesis are as follows.Firstly,combining the driving fatigue generation process with the special driving environment of the extra-long tunnel,the influencing factors of driving fatigue in the extra-long tunnel are analyzed from four aspects: human,vehicle,road and environment.Combined with the existing research,a driving fatigue characterization index system based on eye movement index and vehicle operation characteristic index is constructed,and the related theories of fatigue wake-up are systematically summarized and extracted to lay the foundation for the next research.Secondly,five extra-long tunnels with different lengths and tunnel group sections were selected for natural driving test,and eye movement data of 10 drivers,vehicle operation characteristic data,design parameters and illumination conditions of test sections were collected.Using the difference significance analysis and correlation analysis,the percentage of closed eyes,the coefficient of variation of pupil diameter and the acceleration were selected as the fatigue sensitivity indexes,and the variation rules of fatigue sensitivity indexes under different working conditions were obtained.On this basis,the multi-classification support vector machine is used to establish the fatigue state discrimination model.The Perclos,pupil diameter variation coefficient and acceleration are used as the input variables of the model,and the fatigue level is used as the output variable of the model.The grid search method is used to optimize the parameters.The results show that the discrimination accuracy of the model is 90.75 %.The ordered multiclassification logistic model is used to analyze the influencing factors of fatigue degree.The results show that tunnel illumination,curvature change rate of flat curve and emergency stop belt have little influence on fatigue,while tunnel length and cumulative travel time have great influence.The quantitative model of driving fatigue in extra-long tunnels is established by using the index of the Perclos,which is the explanatory variable with the largest trigger factor in the ordered multi-classification model,and the threshold values of driving fatigue in extra-long tunnels are calculated to be 2.01 and 3.37,that is,when the Perclos increases to 2.01 times of the Perclos before entering the tunnel,the driver begins to produce fatigue.When it increases to 3.37 times,it is considered that the driver enters the fatigue state.The research results provide a theoretical basis for the location of the fatigue wake-up area of the extra-long tunnel.Thirdly,based on the theory of fatigue wake-up and the principle of action,this thesis defines the fatigue wake-up area of the extra-long tunnel as an area with a certain length in the middle section of the extra-long tunnel that is prone to or aggravates the degree of fatigue.In this area,the driver ’s visual,auditory,tactile and other senses provide strong stimulation,which can enable the driver to return to the optimal wake-up level range in a short time.The key parameters such as the location of the fatigue wake-up area,the minimum length of the limit,the form and height of the cross section,and the traffic guidance design are theoretically calculated and designed.The results show that when the tunnel length is 3-5km,a fatigue wake-up area is set in the middle of the tunnel;when the tunnel length is 5-10 km,a fatigue wake-up area is set at 2700 m from the tunnel entrance,and a second fatigue wake-up area is set according to the actual situation of the tunnel.When the tunnel length is greater than 10 km,two or more fatigue wake-up areas should be set up,and the setting positions should be 2700 m and 7100 m away from the tunnel entrance.The minimum limit length of the fatigue wake-up zone is 130 m;both sides of the cross section of the fatigue wake-up zone should be widened gradually,with a width of 1.5m and a length of 2m.The bottom height of the fatigue wake-up zone should not be less than 3.7 m.The fatigue wake-up area warning sign ‘single-row text type’ warning sign sample size is 90 × 530 cm,and the ‘double-row text type’ warning sign sample size is 150 × 240 cm,and ensure that the driver ’s visual distance is unobstructed within 130 m before the fatigue wake-up area warning sign.Finally,the color type and setting length of the fatigue wake-up area are verified by dynamic test,and the effectiveness of the fatigue wake-up area is comprehensively evaluated.The results show that the optimal length of the fatigue wake-up area is 200m-250 m.The wake-up effect is not only related to the color type,but also affected by the driver ’s driving speed.The fatigue wake-up area with cold color tone has the wake-up effect and has the least impact on the driver ’s tension.Therefore,the fatigue wake-up area proposed in this thesis has a good effect on alleviating the ’ short-term fatigue ’ of drivers,and provides a new idea for the fatigue wake-up technology of highway extralong tunnels in China. |
