Study On The Optimization Of Exit Signs On Freeway Interchange

The interchange off-ramp in the freeway is an accident-prone spot.According to the domestic and foreign statistics,accidents happening within 500 meters of off-ramp account for about 30%of all freeway accidents.Moreover,the accident rate at the off-ramp is significantly higher than that at the on-ramp.In the study,it found that some drivers with poor driving behaviors delay changing lanes and go through the off-ramp.They change from the innermost lane to the outermost one near the exit.As a result,vehicles behind have no time to respond so that accidents happen,such as rear collision and side tumbling.In addition,for some drivers who aren't familiar with the exit,locating and seeking problems are particularly prominent due to too detailed exit advance guide sign and the variety of information available for selection.Drivers neglect or misunderstand the information of exit advance guide sign such as 2km,1km and 500m during the driving process.They decelerate,stop and hesitate at the interchange exit triangle due to their mental stress.Then they observe the exit core sign at the distributing spot of exit and reselect whether to enter the ramp or go back to the freeway.In this thesis,exit signs of freeway interchange are studied on the basis of violation behaviors of drivers.The thesis aims to improve the safety of off-ramp,based on the relation between the situations of drivers' violation in interchange off-ramp and the current exit core signs at freeway interchange off-ramp.In addition,the statistics of surveillance video are copied and read through the investigation of four typical interchanges in Hunan freeway so as to get volume of wrong driving behaviors and traffic volume of divided lane and classified vehicle types.Furthermore,by using one-factor analysis of variance,in the thesis,three factors which have impact on violation behaviors,such as time,traffic volume and exit sign setting,are analyzed.At last,the thesis will provide some suggestions for the optimization of current freeway exit guide signs.First of all,through combining with relevant research of domestic and foreign scholars on exit guide signs of freeway,the influences of road,traffic,human,and traffic environment on ramp safety are studied in this thesis according to the basic theory of traffic sign design and setting.Secondly,by reading the relevant surveillance video in interchange,the data of wrong-driving vehicles,the main form of violation,the probability of violation and traffic volume are classified,moreover,the statistics are analyzed preliminarily.Therefore,these measures will provide data support for the research.Finally,survey data and one-factor analysis of variance(ANOVA)are applied in studying the influences of different factors on the number of violation behaviors,which can get the result of certain remarkable influencing factors on the violation behaviors.Furthermore,optimization suggestions for exit signs of freeway interchange will be concluded through combing analysis of remarkable influencing factors on violation behaviors and on the basis of the national standard setting examples.