Study On Plane Line And Location Direction Advanced Information Setting Of Ramp Junction Based On Analysis Of Driver's Visual Identity

When the driver enters the expressway from the toll station at the ramp,the diversion part of the connection between the ramp and the expressway is the only way which must be passed.So the safety at the diversion part is particularly important.The hot issue of existing researches about the interchange is the diversion and the interflow part of the main line,where driving speed is higher.And the diversion at the ramp with lower driving speed is often neglected.Moreover,as the standard required,the linear index at the diversion part of the connection between the ramp and the expressway should be controlled by recognition sight distance.And the recognition sight distance is 1.25 times of the stopping sight distance.However,during the process when the driver drives from the toll station to the nose of the diversion at the ramp,the driver needs to complete the discovery,identification,reading and understanding of the direction signs at the triangular diversion area.And the driver has to make the decision and take the action at the same time.The existing recognition sight distance can not meet the needs of this sign recognition process.Therefore,in order to ensure that the driver enters the expressway safely and comfortably through the diversion part of the connection at the ramp,it is necessary to analyze the visual recognition process and the recognition sight distance of the signs at the diversion part of the connection between the ramp and the expressway.The analysis should base on the driver's visual characteristics.And the geometrical index at the diversion part of the connection can be calculated according to the analysis.At the same time,the method of setting the location and direction advance information is proposed for the road section with poor sight distance.First of all,this research performs an experiment on the visual recognition distance of the signs and the static recognition time.This paper introduces the concept of PCF(The area Proportion of a Character to the Frame,the area of the Chinese character's proportion of the fame's area),and establishes the relationship between the PCF,the horizontal rotation angle of the traffic sign and the visual recognition distance of the sign.Then the different combinations of the surface elements on the direction sign are used to establish the model of the visual recognition time.Secondly,considering the geometrical size of the toll station at the ramp and the position of the direction signs at the triangular diversion area,this paper establishes a model,which describes the visual recognition process of the signs at the diversion part of the connection between the ramp and the expressway.Thus,the shortest distance between the toll station and the nose of the diversion at the ramp,the visual recognition distance of the sign at different distances and different design speeds,and the recognition distance of the nose of the diversion at the ramp is attainable.According to the sight distance of the visual recognition and the relationship between the horizontal rotation angle of the traffic sign and the visual recognition distance of the sign,the calculation process of the horizontal rotation angle of the direction sign is established.Then,based on the analysis of the view point and the object point,the paper calculates the minimum radius of the circle under different conditions according to two values of the recognition sight distance.And methods of setting the location and direction advance information are proposed for the horizontal curve with poor sight distance.The process of sign recognition is used to check and ensure the setting position of the advance information.Finally,the methods of setting the advance information with different circle radiuses and different locations are considered.10 sets of experimental schemes are established to carry out simulative driving experiments.The driver's visual characteristic data and driving behavior data are collected by eye tracker and UC win/road,and they are further analyzed.Experiments show that the choice of the circular curve radius should follow the following rules: if conditions permit,the radius of the circular curve should meet the nose recognition sight distance;the sign recognition sight distance should be met,and the rational advance information of location and direction should be set;try to avoid the circle curve radius that does not meet the sign recognition sight distance,or the rational advance information of location and direction should be set;avoid the circle curve radius that does not meet the 1.25 times of stopping sight distance.