Study On The Information Volume Of Prairie Highway Traffic Signs Based On Driver's Visual Characteristics

Road traffic sign information is an indispensable part of road traffic man-machine environment system information,Reasonable traffic sign information volume can induce drivers to drive efficiently and safely,The insufficient or overload of traffic sign information volume will result in the driver's visual recognition and cognition,which will have a negative impact on driving.Early research found that the unreasonable setting of traffic sign information volume of grassland road is common and serious,which brings safety risks to grassland road driving.Because the proportion of drivers who rely on visual behavior to obtain information of external road traffic environment is more than 80%,it is very important to study the suitability of grassland road traffic sign information volume based on drivers' visual characteristics.Based on the National Natural Science Foundation project,this paper combines the basic theories of traffic engineering,ergonomics,traffic safety psychology,etc,taking the traffic sign information volume,driving speed and driving experience as the main control variables,this paper analyzes the changing rule of driver's visual attention---visual stability---visual load,and finally summarizes and puts forward the appropriate range of traffic sign information volume in the straight section of grassland highway.This study provides a reference for the setting and optimization of grassland road traffic signs,improving road traffic safety and in-depth study of road traffic man-machine environment system.The main research results of this paper are as follows:(1)Combined with the psychophysiological significance of the driver's eye movement indicators,the main component analysis is used to extract the driver's eye movement indicators.Finally,three indicators are selected to reflect the driver's eye movement behavior sensitive indicators affected by the traffic signs information volume in the driving process:the fixation duration,the saccade duration and the saccade range.(2)When the driver sees the traffic sign information amount,the frequency of video injection shows exponential distribution,the frequency of video scanning shows Gaussian distribution,and the frequency of scanning shows exponential distribution;the three eye movement indexes reach the threshold value under the S3 information amount condition(20-30bits/km),under this condition,the driver has strong ability to acquire and process information,high search efficiency and strong identification ability,which is conducive to safe driving.(3)The binomial relationship between the driver's fixation entropy rate and the information volume increases first and then decreases.Under the condition of 20-30bits/km information volume,the fixation entropy rate is the largest,which indicates that under this condition,the driver's visual scanning has strong randomness and the attention allocation strategy is better,that is,the driver can obtain more traffic environment information in the same time,which is conducive to early detection of dangerous information,so as to ensure driving safety.(4)The change of traffic signs information volume has a significant impact on drivers' one-step fixation transfer probability and stability probability.Under the condition of 20-30bits/km information volume,drivers' visual attention distribution is more comprehensive,and cognitive process and visual search strategy are more flexible.The change of speed has no significant effect on it.The visual search strategy of skilled drivers is better than that of unskilled drivers,and the latter needs to be improved.(5)In this paper,a comprehensive index of visual load intensity is proposed to represent the influence of traffic signs information volume on drivers.Under the condition of 20-30bits/km information volume,the visual load intensity is the smallest,and the average load of unskilled drivers is higher than that of skilled drivers.The subjective load of drivers is evaluated and verified by NASA-TLX,and the results of subjective load assessment is consistent with that of objective analysis.(6)Considering driver's visual attention characteristics,visual transfer stability characteristics and visual load intensity,it is suggested that the traffic sign information of straight road section of grassland highway should be set in the range of 20-30bits/km.