Study On Spacing Arrangement Of Protruding Raised Pavement Markers At Freeway Exit Ramp Based On Visual And Vibration Simulation

At the exit ramp of the freeway,the road alignment changes quickly,the driving environment is complex,and there are many hidden dangers of driving safety,especially in the bad weather or at night and other low visibility weather conditions,if there is no suitable road safety guidance facilities,it is difficult to identify ramp exits,often leading drivers to miss road exits or discover that exits fail to trigger a series of traffic accidents in time,and traffic accident rescue and evacuation difficulties at freeway exits are particularly prone to secondary accidents,Causing certain loss of life and property.As a guidance device for road traffic safety,Raised Pavement Markers(RPM)have two functions: reflection characteristics and vibration warning.Under the condition of low visibility,the RPM can give full play to the warning effect of line of sight through self-illumination or reflection illumination of headlight.When the RPM on the road surface is compacted,it can produce vibration effect to provide people with vibration warning function.In this paper,visual induction simulation and vibration effect simulation are used to study the interval setting of the RPM at the exit of expressway.The main contents of this study are: Firstly,combining the driver's visual features,flickering visual stimuli with the reflective features of the RPM,determining the setting interval of the RPM at the deceleration lane markings at the freeway exit ramps,the triangle area and the ramp curve and the setting of the starting position at the exit of the expressway.Secondly,through visual simulation test,the interval of the protruding signpost in the triangular region of nasal flow was determined.Different types of freeway ramp exit model,protruding RPM model and vehicle model are established on the driving simulator of UC-win/Road.In the driving simulator,30 drivers were asked to simulate the scene at the ramp exit of the freeway at night to select the appropriate setting interval for the triangular region protruding in the nostrils.Thirdly,the establishment of dynamic simulation model of man-chair-car-road vehicle.In SolidWorks,we create a three-dimensional human body sitting posture model that conforms to the human body size of Chinese adults.The corresponding seat model and the "9-DOF chair system model" are constructed according to certain constraints,and the man-chair model is imported into the multi-dynamic simulation software Adams through the interface file.Based on Adams/Car,the dynamic simulation model of the whole vehicle is established,and the freeway exit ramp model and the protruding RPM model with different intervals are created.Fourth,the vibration simulation and effect analysis of the RPM.Based on the simulation model of man-chair and vehicle-road,the scheme design of the vibration simulation test of the protruding RPM is carried out and the simulation test is carried out according to the simulation scheme.The simulation data are analyzed according to the theory and method of ISO 2631-1: 1997.In the Ncode data analysis software,edit the calculation data analysis flow of the human body comfort degree evaluation,get the weighted acceleration RMS value that is the subjective feeling of the human.Thus,the method of setting the gap of the RPM with both visual induced warning and vibration warning effect is selected.In this paper,the RPM setting at the exit of the expressway is studied.When the traffic flow at the exit of the freeway at night needs to increase the induced safety effect of the safety facilities at night,In the deceleration line,the interval of the protruding RPM can be 6 m.If considering the economy and maintainability,the distance of 9 meters can be chosen;In the triangular region,the RPM is set at 6m,and in the ramp with a radius of more than 700 m,the interval is 15 m.The other radii are set according to the relation between the setting interval of the bulge sign and the ramp radius obtained in this paper.Based on the visual and vibration simulation,this paper makes a scientific study on the setting interval of the RPM at the exit of the expressway.The results of the research can provide reference and suggestions for the relevant contents of the current laws and regulations.