Study Of Driving Stability On Sandy Highway Sections Based On Driver Psychological Load

The impact of sand on desert highway roads on driving safety is twofold:firstly,it greatly reduces the anti-slip performance of asphalt pavements,and secondly,sand on roads increases the psychological load of drivers,leading to unsafe driving behaviour.To this end,the study of driver driving stability under sandy road conditions is carried out to provide.some theoretical and practical guidance to ensure road driving safety in desert areas.In this thesis,the pendulum value BPN of asphalt pavement under different sand accumulation conditions was firstly examined to study the influence of different sand accumulation on the pendulum value BPN,and the dynamic friction coefficient of pavements with diferent sand accumulation thicknesses on uphill,downhill and cornering roads was measured by using the braking distance method to obtain the dynamic friction coefficient change law of the corresponding state.With the increase of sand accumulation,the pendulum value of BPN of asphalt pavement shows a gradual decrease first and then tends to be stable.In the uphill,downhill and curved road sections,when the sand accumulation state of the pavement was from no sand accumulation to the basic coverage of 0-2mm,the decline of dynamic friction coefficient was 21.37%,30.1%and 21.45%respectively;and then with the increasing amount of sand accumulation,the final friction coefficient value would tend to be stable or rebound in a small extent.And the decay rate of dynamic friction coeffi cient is basically the same as the decay rate of BPN.Secondly,in this thesis,a driver test was carried out to collect and analyse reliable indicators of driver psychological load and driving stability under different road sand conditions and different road alignment conditions:the indicators of driver psychological load include 8 ECG indicators such as HR,SDNN,MEAN,RMSSD,PNN50,LF,HF,LF/HF and 3 EEG indicators such as β-wave power spectral density integrated value,δ-wave power spectral density integrated value and α/β value.The results showed that the driving stability was not affected by the road area.The results show that there are differences in drivers’ mental load levels and driving stability under different road sand conditions and different road alignment conditions.As the thickness of road sand increases,the driver’s ability to perceive and process information decreases,resulting in a more stressful,alert,agitated or fatigued psychophysiological state and a decrease in driving stability.The variable of road sand thickness has a significant effect on most of the cardio-physiological and behavioural characteristics,while the complexity of the road alignment also affects some of the cardio-physiological and behavioural characteristics of the driver.Novice drivers are more alert than skilled drivers in sandy road conditions,and their heart rate and-LF/HF levels are higher than those of skilled drivers;novice drivers make more acceleration and deceleration manoeuvres and have more erratic lateral control of the vehicle,so the variable of driving proficiency has a more significant effect on most indicators of physiological and behavioural characteristics.Finally,on the basis of the previous paper,three comprehensive indicators such as ECG comprehensive indicator,EEG comprehensive indicator and handling behaviour comprehensive indicator were obtained by using principal component analysis to reduce the dimensionality of the indicators,and the entropy value method was used to construct a driver mental load model and conduct K-Means cluster analysis to obtain the classification of mental load under different thickness of sand accumulation on ordinary roads,and to revise the driver mental load under other road alignment conditions.The model is combined with the BP and RBF neural network theories to construct a driver stability identification model based on the psychological load of drivers using real vehicle driving test data Through the study,the concept of highway driving safety protection method under sandy conditions in desert areas is proposed in a targeted manner.