Study On Linear Safety Of Ningxia Expressway Based On Dynamic Visual Characteristics

With the strengthening of the economic strength construction in Ningxia,the people's living standards have been continuously improved,the number of motor vehicles has been increasing,and at the same time the rapid development of expressway construction has caused serious threats to the safety of the vehicles.Ningxia is located in arid and semi-arid regions,with abundant evaporation,and annual precipitation is small and concentrated.It is one of the provinces with the most serious land desertification in China.Most regions have arid and rainy conditions and are ecologically fragile due to arid and semi-arid climate and natural conditions.Affected by geographical location,most of the land in the area is deserted and the vegetation is mainly desert grassland.Although the roads built along this terrain have better linear conditions,they are likely to cause visual fatigue or attention due to the single surrounding environment.The lack of concentration will affect traffic safety to a certain extent.However,at this stage,the "Road Route Design Code" does not study road safety in the special conditions of the desert steppe.This research idea is based on the previous researches of the predecessors,and studies whether the driver's actual driving behavior is adapted to the needs of the driver's actual driving behavior through driver's dynamic vision change,and obtains data through the driving test to find the highway line shape index and the driver's eye movement index.Change the relationship and establish a model,and analyze and discuss the linear indicators based on driver's visual safety considerations in the model.This article selects pilots with different driving levels as test samples,uses Tobii Pro Glasses 2 eye tracker and other equipment to gather eye movement parameters of the driver when driving on a typical highway in Ningxia,and uses Excel,SPSS and other software to statistically process data and summarizes The law of eye movement parameters of the driver.Firstly,the straight section of the typical expressway in Ningxia is selected.The correlation of the visual characteristics of the driver such as the pupil diameter and the gaze point variance with the length of the straight line segment and the speed of the line are analyzed and a model is established to obtain the straight line lengths of the 110 national highway and the typical expressway in Ningxia.The mutation point L0 = 5767,L0 = 774,that is,the driver's maximum distance to reach visual fatigue is 5767m,and is compared with the United States,the former Soviet Union,and the Japanese highway specification values respectively.This value is reasonable;the driver is in the straight line segment.When the travel distance is less than 774m,the pupil diameter changes drastically,that is,the driver is very nervous and obtains the shortest travel time of 28 seconds,which is higher than the minimum travel time of 21.6s on the straight line between the same direction curves required by the regulations.,requires a longer reaction time.At the same time,the point of variance of the gaze point when the driver travels on the 110-country road and the straight section of a typical expressway in Ningxia is:L0 = 5585m,L0 = 3047m.It is found that when the driver reaches the straight section of the 110 national highway and the typical expressway of Ningxia,the distance travels abruptly.At the time of point value,the variance of the gaze point when driving on the highway is significantly larger than that of the gaze point on the 110 national road,indicating that the driver is more likely to have visual fatigue on the highway.The correlation between the curve radius and travel speed and visual characteristics was studied.The radius value based on the driver's visual characteristics was R0=3354.When R<R0,the pupil diameter changed drastically,indicating that the driver was tense,and the proposed value was proposed.It is slightly lower than the minimum radius required by the specification.In the study of the effect of curved slope on speed and pupil diameter,it is found that when the curved slope is large,the pupil diameter of the driver is at a large value,which is unfavorable for driving safety.Finally,the validity of the regression model established by the curve radius,travel speed and pupil diameter of Ningxia typical expressway established in this paper is verified by accident data.