Study On Line-of-sight Induction Technology Based On Freeway Geometric Alignment And Roadside Safety Facilities

Throughout the development of China's highways in recent decades,it can be found that while the rapid development,the accompanying road traffic safety issues have become increasingly prominent.As a black spot of road traffic accidents,the poor line-of-sight-induced sections are particularly prominent in traffic accident rates and the severity of traffic accidents.In order to alleviate the further deterioration of traffic problems,it is very important to set up line-of-sight induction facilities scientifically and reasonably,which can reconstruct the black-spot problems of accidents in poor line-of-sight-induced sections.This paper defines the poor line-of-sight-induced sections from three aspects: horizontal sight distance,vertical section sight distance and nocturnal headlight scattering angle,and puts forward the defining standard of poor line-of-sight-induced sections,which provides the basis for the application of the line-of-sight induction technology in post script.According to the height of the line-of-sight induction facilities,the line-of-sight induction facilities are divided into two categories: plane and stereo.By summarizing and analyzing the research results at home and abroad,it is concluded that at least four stereoscopic line-of-sight induction facilities or six plane line-of-sight guidance facilities should be present in the same field of view of the driver to effectively induce the driver's line of sight.On this basis,according to the driver's nighttime dynamic field characteristics and the horizontal and vertical line geometry of the road,the distance and height calculation model of each line-of-sight induction facility is obtained.Starting from the requirements of the line-of-sight induction facilities with different alignment combinations,the selection and combination of each line-of-sight induction facility is analyzed under different lane numbers and different alignment combination sections.The color and shape of several common line-of-sight induction facilities are also described.According to the type of special road section,the line-of-sight induction facilities are analyzed.Because the road traffic environment such as the section form is the same as the general road section,the bridge section will follow the setting method of the line-of-sight inducion facilities of the general road section;The tunnel section takes into account the effect of the “wall effect” on the driver's psychology,and combines the tunnel section difference to set up the distance calculation model of the line-of-sight induction facility of the tunnel section;By analyzing the serious slope illusion of the long downhill section,the method of setting the line of sight induction column in the vertical curve of the long downhill section is proposed,and at the same time,the premise of ensuring the driver's safety deceleration is taken,the distance between the line-of-sight induction facilities at the starting point of the long downhill section is obtained and give the transition length;Several new line-of-sight induction facilities were analyzed and studied,and specific setting methods were given.The Uc-win/Road simulation experiment is used to further verify the rationality of the distance between the line-of-sight induction facilities.The study results of this paper are helpful to reasonably set the line-of-sight induction facilities,play its instructions,warn the driver of alignment changes,and ensure the safety of driving.It is of great significance to improve the safety of the poor line-of-sight-induced sections.