Research On Calculation Method Of Width And Setting Conditions Of Highway Roadside Clear Zone

By the end of 2016,the total mileage of highways in China has reached 469.63 million kilometers,while roadside accidents cover 1/2 of the total number,howe ver data from Beijing and Guizhou show that in all these accidents,the road one covers 1/4 of all,resulting in a 40 percent mortality rate and more than 50 percent of serious injuries.How to put forward a reasonable and effective roadside safety management method on the basis of theoretical analysis,so as to reduce roadside accident rate and severity,is an important issue that scholars need to solve.At present,China's current "Highway Engineering Technical Standards" and "Highway Engineering Design Standards" are still left blank on the roadside clear zone,and the roadside clear zone setting conditions also lack the corresponding theoretical support.Therefore,this article is for the roadside net area.The width and setting conditions of roadside clear zone were studied.This paper focuses on theoretical analysis and analyzes the main influencing factors of roadside clear zone width,including roadside features,driver behavior,vehicle exit status(exit angle and exit speed),and then proposes a theory based on classical physics.And then a method for calculating the width of the roadside clear zone based on classical physics theory was proposed.The PC-Crash software was used for the simulation test to verified the accuracy of the method.And the recommended value of road clear zone width is given based on the average running speed of the outermost laneStarting from the distribution characteristics and causes of accidents on the roadside of the highway,PC-Crash accident simulation software was used to obtain data and analyze the influencing factors of the severity of roadside accidents,Taking roadside accident severity as the dependent variable,the roadbed height,slope gradient,exit speed,and accident model were selected as independent variables,and a roadside accident severity prediction model based on cumulative logistic regression was established.According to the parameters such as the number of roadside accidents,the probability of different severity accidents,and the economic loss of accidents,a method for calculating the safety benefits of the roadside clear zone is proposed.To quantify the engineering cost of earthwork construction costs and land acquisition costs,a method for calculating the project cost of the roadside clear zone was proposed.Based on the objective planning method,with the maximization of safety benefits in the clear zone as the first goal and the minimization of project costs as the second goal,based on cost-benefit,a decision-making model for the setting of a roadside clear zone was established,and the setting condition of the roadside clear zone was given;A roadside accident risk assessment system was constructed on road sections that were not equipped with roadside clear zones,roadside risk assessment models based on contact numbers were proposed,and barrier fence ratings corresponding to different risk levels were given.With flexible guardrails;through practical engineering cases,using the research results of this paper,an optimized design proposal for roadside safety facilities is given.