Roadside accident-hazard assessment and on-guard protection gradation

In order to reduce the rate of roadside accidents,help traffic-control engineers to make proper decisions and take effective measures in improving highway roadside safety,this article is con- cerned about how to make a reasonable evaluation of the roadside safety and how to set the safety facilities for the different roadside dangerous situations.The traditional method to keep safe from acci- dents is to take a protective barrier,whose setting is to limit the road grades and the potential seriousness of the accidents.However,it is difficult to accurately evaluate the seriousness of the accidents when the barrier design is made.To improve the evaluation,it is essential to learn how to make a reasonable or rational assessment and classifi- cation of dangerous conditions involved from the point of view of the roadside traffic control,as well as the types of protective equipment and facilities in different hazards-involved circumstances.Through a comprehensive analysis of the highway roadside accident causes and the influential factors,the author has put forward a concept of road- side hazard and a roadside hazard-degree evaluation method based on the gray cluster theory.In working out the evaluation efficiency,the proposed method intends to overcome the deficiency of indefinite like- liness of roadside hazards for a specific road segment.For the re- search purpose,we have adopted more than ten variables in our eval- uation model,in which roadside safety performances can be quanti- fied in terms of the level of roadside hazard degrees which can be classified into four grades titled as Ⅰ,Ⅱ,Ⅲ and Ⅳ.The higher the grade,the worse the roadside safety performance is.And then a proper proposal has been put forward as to the types of safety facilities according to the different grades of roadside safety from our case study experiences.The results of the trial application of the method provid- ed here demonstrate that it can perspicuously and accurately reflect the effects of the related roadside factors on the traffic safety in a complicated system.This evaluation method and its approaches to the hazard gradation prove to be useful for the road engineers and deci- sion-makers to identify and evaluate the traffic hazards of the exact road segments under discussion that need a safety improvement and then determine the protective measures to be taken to meet the need.