Research On Key Alignment Indicators Of Two-Lane Highway In Plateau Based On Drivers’ Physiological Characteristics

The climatic and environmental conditions in the plateau area are characterized by low pressure and low oxygen,which are obviously different from those in the plain area.Since the special environment of low pressure and low oxygen would affect the psycho-physiological status of drivers,the psycho-physiological load of drivers in the plateau area would increase,which would affect the driving safety in the plateau area.At present,the influence of driver factors has been emphasized in the design of highway alignments and due to the differences between the natural environment of the plateau area and the plain area,it is necessary to consider the impact of low-pressure and low-oxygen environment on the driver factors in the design of the plateau highway alignment.From the perspective of the driver’s psycho-physiological characteristics,this paper analyzes the impact of the low-pressure and low-oxygen environment,and then studies the safety of the key indicators of alignment applied on the two-lane highway in plateau area.Firstly,based on the environmental characteristics of the highway and the current status of traffic safety,the paper analyzes the impact of drivers,vehicles,highways and environmental factors on the driving safety on highway in the plateau area,and determines the main influencing factors of driving safety on the two-lane highway in plateau area are the low-pressure and low-oxygen environment and highway alignment.Secondly,a typical two-lane highway in plateau area is selected and the corresponding simulation model is constructed,after which on-site driving experiments and indoor simulation experiments in the plateau area are conducted.The psycho-physiological parameter data and driving behavior data of the tested driver are collected by biofeedback.Then,the driver’s psycho-physiological parameter data is analyzed with sample entropy,and the fact that the sample entropy of the psycho-physiological parameter data in indoor and outdoor experiments in the plateau area is consistent is obtained,which indicating that it is effective to conduct indoor simulation experiments in the plateau area.Afterwards,principal component analysis(PCA)is applied to obtain the comprehensive indicator of sample entropy(CISE)that comprehensively characterizes the driver’s psychological and physiological workload characteristics,and a method for determining the threshold value of the CISE is proposed to indicate the driving safety.Then,the influence of altitude factors on the CISE is analyzed,and the altitude section of the experimental highway section is divided into four sections,after which,the relationship between the key alignment indicators and driving speed of the horizontal curve section and the combined curve section in different altitude sections is studied,and the corresponding mathematical regression models are obtained.Afterwards,with the independent data reserved by the experiment,the validity of the regression model is verified.Finally,according to the safety threshold of the CISE,the critical values of the key alignment indicator of the two-lane highway in different altitudes are determined,on the basis of which,the critical values of the key alignment indicator are compared with the current specifications,after which,the recommended values are proposed.Besides,the traffic accident data in the plateau area are applied to demonstrate the rationality of the recommended value of key alignment indicators.In this paper,by analyzing the psycho-physiological workload of the driver in a low-pressure and low-oxygen environment of the plateau,the relationship between the key alignment indicators of the horizontal curve section and the combined curve section of the two-lane highway and the psycho-physiological workload of the driver are established,after which,the recommended values of the key alignment indicators of the plateau two-lane highway are proposed.The research results are of theoretical significance and good practical value for improving the driving safety of the two-lane highway in plateau area.