Study On Driving Trajectory Characteristics And Driving Risk In Hairpin Curve Section Of Mountainous Highway

Traffic accidents occur frequently in complex road alignment in mountainous areas,and the consequences are serious.However,there are few researches on complex alignment in mountainous areas,and the general driving characteristics of drivers on this road are unknown.It is urgent to provide reference for the road safety,improvement of alignment and simulation scene construction of complex lines in mountainous areas.Hairpin curve as a typical representative of complex linear highway in mountainous area,the behavior of drivers reflects the driving characteristics under the limit conditions,which has reference value.Therefore,in order to explore the potential danger caused by the conflict between the characteristics of driving track and various track modes under the hairpin curve in mountainous areas,this paper takes the two lane four class highway of G211 line in Pengshui of Chongqing as the test object,uses the high-precision GPS data acquisition instrument speed box to collect the driving data of natural driving real vehicle test,and uses the on-board dash cam and mobileye and other auxiliary instruments record the distance between the real-time driving state of the vehicle and the marginal line of the wheel,so as to reduce the error of later test data analysis.Through the processing of the vehicle driving data collected,the driving tracks of all drivers at each curve are restored,and the main conclusions are as follows: trajectories at curves have different agglomeration and dispersion characteristics,and trajectories at curves can be further subdivided into 6 modes.The reduction rate of entry velocity is closely related to the presentation of different types of trajectories.Most of the curvature values of the right-turn trajectory at the hairpin curves are greater than the road curvature,and there are differences between the overall curvature and the road curvature.The equivalent radius obtained from the average curvature value of the circular curve segment has certain difference between the left and right rotations,and it is related to the slope direction and the angular velocity of the curve.The trajectories of different trajectories may conflict with each other,which can be divided into three categories based on the conflict mode and regional distribution.The three fitting model with different trajectory patterns was constructed based on the relationship between the offset pattern of the trajectories and the distance after the curve,and was verified to be applicable to the trajectory pattern reappearance of the rest of the curve at the corner of the curve.Through the division of trajectory pattern and calculation from the characteristics of the trajectory curve,identification of driving risk area,and general comparative study of bend and hairpin curve,which can reveal the driving style and accident formation mechanism of mountainous complex linear highway,provide data support for traffic safety facilities,alignment design,safety evaluation and management of hairpin curve.At the same time,the predicted trajectory model can provide a method for the prediction of driving trajectory at the hairpin curve,and provide an effective support for the construction of driving simulation model on mountain roads.