Research On Traffic Safety Analysis And Setting Up Truck Escape Ramps For Continuous Long And Steep Downgrades Of The Freeway

Continuous long and steep downgrade sections are often black-spots. Setting up truck escape ramps,linear measures, traffic engineering measures and management measures are measures to solve the traffic safety problem in continuous long and steep downgrade sections. It has been proved in practice that setting up truck escape ramps is one of the most effective engineering measures by now. Because of the construction cost and maintenance cost of a truck escape ramp is high,it is important to set up truck escape ramps reasonably. So strengthen the research of the principle has significance for solving the problem of setting up truck escape ramps.This paper analyses the relevant information and documents. It analyses the safety of the typical continuous long and steep downgrade sections in Chinese freeways, including analysis of traffic characteristics, cause of the accident and the mechanism of truck accident, it is the premise of studying setting up safety infrastructure reasonably in the continuous long and steep downgrade sections. This paper discusses the impact of the dynamic road traffic system to the traffic safety respect from the micro-mechanism, and the dynamic road traffic system is composed of people, vehicles and road traffic environment.This paper collects the linear conditions and the accidents of the continuous long and steep downgrade section in Beijing-Zhuhai Freeway K39 ~ K52 (south), through the analysis and the processing of this data, it builds up a BP neural networks model of the traffic accident rate in the continuous long and steep downgrade sections with the MATLAB neural network toolbox, this model is about the length of slope, the grade of slope, the cumulative length of slope and the cumulative average grade of slope. And this paper uses the prediction model to predict the accident rate to provide data for setting up truck escape ramps.This paper uses the traffic accident rate prediction model and the brake temperature prediction model to give comprehensive security analysis to the continuous long and steep downgrade sections in the preliminary design stage of the Chengde-Qinhuangdao Freeway, and then it determines the location of truck escape ramps combined with practical linear and terrain conditions. It can provide basis of theory method and practice for the safety evaluation in continuous llong and steep downgrade sections of the freeway.