| Prairie is the main landscape type in Inner Mongolia Autonomous Region.The traffic volume of grade highways distributed in prairie is small,the linear variation is little,and most of them are long straight lines.The landscape environment of road domain is single,which can not provide drivers with appropriate visual information.Thus,the landscape of prairie highway is a typical monotonous environment.It is easy to cause drivers’ mental fatigue,decrease drivers’ alertness,reduce judgment and decision making ability,thus threatening traffic safety.Through the investigation of typical prairie hightway in the Inner Mongolia autonomous region,it is found that the proportion of straight line length is between 87.79% and 91.19%,and the proportion of straight line length which is higher than the maximum straight line length of 5170 m which meets the drivers’ psychological and physiological needs is between 33.62% and 74.17%,and the longest straight line even reaches16045.72 m.Studies show that 81% of fatigue-related accidents occur on straight roads.Therefore,it is a necessary means to reduce the harm of monotony for traffic safety to carry out landscape intervention in the straight section of prairie highway.Current studies have proved that intervention of afforestation landscape has the advantage over vehicle-task in solving environmental monotony.The research on the influence of afforestation landscape on drivers has the following characteristics:(1)The attributes of afforestation landscape are separately distributed in the degree of enclosure,color,spatial layout,length threshold and richness of plant furnishing etc.There is still a lack of studies on afforestation landscape that integrate the above attributes,let alone the research on landscape intervention in the special monotonous environment of prairie highway by using afforestation landscape as a way to improve drivers’ alertness;(2)There are a large number of studies focusing on the influence of green landscape on driving behavior,while the researches on drivers’ psychology and physiology are independently distributed in ECG(Electrocardio-graph),EEG(electroencephalo-graph)and visual characteristics,but the researches on drivers’ alertness on psychology&physiology and visual characteristics are not studied comprehensively.Since the drivers are the subjects of the man-machine traffic environment system,80% of the road environmental information is obtained by vision,furthermore the essence hazards of monotony is reducing alertness,so the comprehensive influence of afforestation landscape on the drivers’ alertness and visual characteristics should be studied.Based on the above background,the core of this study is to effectively solve the traffic safety hazards caused by monotonous prairie highway through scientific afforestation means.According to the characteristics of regional climate,hydrological conditions,ecological environment and regional culture,the suitable plant types for prairie highway afforestation were selected.With the help of literature analysis and traffic regulations,the plant furnishing with comprehensive closure degree and color collocation is designed.Three types of effective plant furnishing are selected through expert scoring method and simulated driving experiment as afforestation plans.On this basis,the evaluation of the afforestation plans based on drivers’ alertness and visual characteristics is carried out to reveal the effect of the afforestation plan as a visual stimulus to improve the alertness by affecting drivers’ visual characteristics,so as to determine a reasonable afforestation plan.In order to improve the landscape environment of prairie highway,reduce the monotonous harm,enhance the driving safety and improve the function of prairie highway system.In addition,this study has theoretical and practical significance for the researches of inducing drivers’ eye movement behavior to improve drivers’ alertness and road environment optimization.The main achievements are as follows:(1)Through the investigation of road traffic environment,driving videos of 9highways including 3 typical prairie highways were collected,and the monotony of road environment was quantitatively evaluated by compression rate using MPEG video compression technology.The conclusion was that the monotony of prairie highway is higher than that of non-prairie highway.(2)The real driving experiment proved that the compression rate is strongly correlated with the alertness represented by EEG-[(alpha+ Tehat)/ Beta],which improves the reliability of MPEG compression technique for evaluating the monotony of road environment from the alertness of drivers.At the same time,the lack of monotony evaluation of MPEG video compression technology based on drivers’ EEG verification is supplemented.It provides a theoretical support for integrating MPEG video compression technology into the contactless detection system of autonomous driving to improve the detection depth of the environment and reduce the false positives of the existing fatigue monitoring system.(3)According to the characteristics of regional climate,hydrological conditions,ecological environment and regional culture of prairie highway,suitable plant types are selected.According to the classification standard of open,semi-open and semi-closed,16 kinds of plant furnishings of prairie highway were designed.With the help of expert scoring method and simulated driving experiment,three reasonable plant furnishings were selected: L1 Galsang flowers,L2 Galsang flowers +Chinese pine(with 400 m interval)and L7 small Chinese tamarisk +ammopiptanthus.(4)Three types of reasonable plant furnishings were used to form three types of afforestation plans: S1 Galsang flowers,S2 Galsang flowers + Chinese pine(with400m interval)and S3 small Chinese tamarisk + ammopiptanthus.Through the driving simulation experiment,this paper analyzes the different influences of afforestation plans on the drivers’ alertness and visual characteristics,S2 Galsang flowers + Chinese pine(with 400 m interval)has the effect of improving the saccade frequency and fixation frequency of drivers on the premise of ensuring the optimal alertness.Furthermore this effect is of optimal for all drivers and drivers on different genders and experience.Therefore,it is suggested to adopt S2 Galsang flowers +Chinese pine(with 400 m interval)for afforestation plan to prairie highway.(5)In order to avoid the accumulation of afforestation plan in time to form a new monotony,resulting in the reduction of drivers’ alertness.Based on ROC curve,pupil diameter and EEG Sample Entropy,the optimal afforestation plans S2 of Galsang flowers + Chinese pine(with 400 m interval)was determined to be 12 km. |
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