Research On The Information Volume Of Traffic Signs In The Straight Section Of Grassland Highway Based On HRV

Grassland road has the characteristics of single landscape,flat terrain,less traffic,mainly long straight line and large radius curve,and less stimulating driving environment often makes drivers in a monotonous state,easy to make the driver relaxed vigilance,attention drop,processing information ability to reduce,induce mental fatigue lead to wrong control behavior,serious lead to traffic accidents.When driving on the grassland road,the information of different traffic signs has different effects on drivers' psychology.In the long straight-line-oriented grassland road,insufficient or overload traffic sign information will affect the driver's mental state,Operation Level and recognition degree of road condition.Related investigation shows that more than 80%of the grassland highway traffic signs lack of information.Based on the above problems,this paper analyzes the relationship between the traffic sign information and the driver's heart rate variability under the simple landscape environment,and then reveals the influence of the traffic sign information on the driver's heart rate variability.The heart rate variability index which is sensitive to the change of traffic sign information is determined by using the method of grey correlation analysis,the heart rate variability(HRV)of drivers with different experience and different speed at different traffic sign information levels is analyzed and tested.The results show that the HRV of drivers with different experience at 60 km/h and 80 km/h driving speeds is higher than the HRV of drivers with different speed,the reliability of the conclusion was verified by subjective questionnaire and driving experiment,which provided a theoretical basis for the setting of traffic signs on grassland road.The main findings of this study are as follows:(1)By using the method of grey relational grade analysis,the heart rate variability index MRR(RR interval mean value,RR is the interval between two R waves),RMSSD(root mean square of the difference between two RR intervals),SDNN(standard deviation of RR interval)and D2(a method for measuring the complexity and singularity of time series)were identified as the sensitivity indexes,it can well reflect the psychological changes of drivers in different traffic sign information levels on the straight road section of grassland highway.(2)There were significant differences in heart rate variability(except 80km/h,MRR)between experienced drivers and non-experienced drivers under the condition of the change of traffic sign information grade on the straight road section of the grassland road,experienced drivers are relatively inexperienced drivers,more focused,less load,can adjust their own state of mind to obtain effective information,strong ability to adapt to the environment.It is concluded that driving experience is the influencing factor when studying the influence of traffic sign information on HRV(heart rate variability)of drivers.(3)The proposed setting grade of traffic signs per km is Z3 at 60 km/h and 80 km/h on straight-line section of grassland highway.(4)Subjective questionnaire and driving experiment were used to test the validity of the traffic signs,and the results showed that when the information level of the straight-line section of the grassland road was Z3 per kilometer,the drivers were most attracted to the traffic signs and got the effective information,to make the conclusion more convincing.