Research On The Psychological Load Of Mountain City Interchange Based On Natural Driving

In urban interchange design,planning urban interchange based on traditional road linear design theory is a common method,but it is not ideal in practical applications,such as smaller ramp radius,poor driving line of sight,and large difference in speed from the main line,making the urban interchange become a high-incidence section of the accident.In traffic accidents,human factors are the main cause of road traffic accidents.Driving psychological load in driving has a great impact on driving safety.The level of psychological load directly affects the stability of the driver’s operation.Therefore,it is of great significance to study the traffic safety problem of the interchange from the perspective of the driver’s psychological load.It can provide a certain reference for the design of mountain city interchanges.At the same time,it can improve the safety of urban interchanges and prevent traffic accidents.This study starts from the perspective of traffic psychology,studies the formation mechanism of driver’s psychological load,focuses on the impact of four factors: human,vehicle,road and environment on driving psychological load,summarizes psychological load related evaluation indicators,Finally,the heart rate growth rate and heart rate variability index RMSSD are selected as the evaluation index of driver’s psychological load.Secondly,the road test is carried out on the crotch-leaf and spiral-shaped interchanges,and the psychological characteristics data,the intersection line parameters,the vehicle operating parameters and the road traffic environment information of the subjects in the natural driving environment are obtained.Finally,based on the measured data,the statistical analysis method is used to analyze the test data.The external factors affecting the psychological load are mainly the driving environment of the vehicle.The three modes of following the car,overtaking and meeting are the main factors leading to the increase of the driver’s psychological load,The influence of the meeting mode on the psychological load is greater than the first two modes.Secondly,the driver’s psychological load rise in the split nose is common,and the rising amplitude is affected by the main traffic.The intrinsic factors affecting the psychological load are mainly the driving proficiency and the familiarity with the road.Both factors are negatively correlated with the psychological load.Based on the statistical analysis of relevant evaluation indicators,the study found that the mental load of the uphill ramp driver is higher than that of the downhill ramp,regardless of the circular ramp or the spiral ramp.The mean value of the heart rate growth rate of the circular uphill ramp is “negatively skewed”,while the downhill ramp is “positively skewed”;The mean HRI of the uphill ramp was mainly distributed from 8.34% to 15.00%,and the mean HRI of the downhill tunnel was mainly distributed between 6.67% and 13.34%;The average RMSSD distribution of the up-and-down ramp of the spiral interchange is “negatively skewed”;the mean RMSSD of the uphill ramp is mainly distributed at 13.75-22.50 ms,and the mean RMSSD of the downhill ramp is mainly distributed at 12.50-20.00 ms.The relationship between the driver’s psychological load and the line shape of the interchange is studied.The results show that there is a strong correlation between the radius of the ramp and the psychological load,and the psychological load is negatively correlated with the radius of the ramp.Three different types of driver ramp radius and HRI relationship models are established for the ring interchange ramp,and three different types of driver ramp radius and RMSSD relationship models are established for the spiral interchange ramp;At the same time,for the spiral interchange,the relationship between slope and RMSSD shows two different modes of change,and the relationship model between slope and RMSSD is established.