Study On Safety Assessment And Guarantee Measures Of Long Downhill Section Of Mountain Expressway

At present,the situation of highway traffic safety in mountainous areas in China is still grim,especially in the long and downhill sections,which account for about half and more of the total road accidents,and most of them are major or larger traffic accidents.The number of accidents caused by brake failure or heat recession of heavy trucks in the long downhill sections is relatively large.It has caused huge losses to people's lives and property security,which is a prominent problem restricting China's economic and social development.Therefore,relying on the scientific and technological projects of Henan Province Transportation Department,"Research on Traffic Safety Optimization and Guarantee Measures of Mountain Expressway" and "Research on Operation Control Technology of Henan Expressway Based on Traffic Behavior Safety"(Project No.2019G-2-11),this paper studies the safety evaluation and safeguard measures of long downhill section of mountain expressway.Firstly,according to the field investigation data,aiming at the hidden dangers existing in the special linear section of Luoyang-Luanchuan Expressway(hereinafter referred to as Luoluan Expressway),the accident forms and their influencing factors of the special section of long downhill are analyzed from three aspects: speeding,overloading and the speed of vehicle braking failure,and it is concluded that all of them can increase the probability and severity of traffic accidents.Secondly,the safety characteristics of the running speed of the long downhill section are analyzed,and the traffic capacity and service level of the road are emphatically analyzed based on the actual data.The traffic volume,the design hour traffic volume and the saturation and service level of the four long downhill sections of the Luoluan Expressway are predicted.Then a new brake drum temperature model is established by modifying GSRS model,and the brake drum temperature of heavy trucks on long and downhill sections in mountainous areas with different weights and running speeds is predicted.Combining with Trucksim simulation software,the vehicle model and road model are established to simulate the driving safety of heavy trucks on long and downhill sections under real conditions,and the brake of heavy trucks is simulated.The drum temperature prediction models are checked each other to evaluate the safety of long downhill sections.The results show that in the upper K24-K29 section,the upper K29-K34 section,thedownward K8-K3 section and the downward K36-K31 section of the Luoluan Expressway,the temperature of the brake drum is predicted based on the revised temperature prediction model of the brake drum at the running speed of 30 t,40t and 55 T respectively.The model based on TruckSim software is used to predict the acceleration of the brake drum at the running speed of 30 t,40t and 55 t,respectively.The line chart shows that,When the vehicle is overspeed or overloaded,the brake drum temperature of the vehicle will exceed the safety temperature of 200 C,which will lead to brake failure or failure,and the vehicle is in dangerous state.Comparing the simulation results with the calculation results of the brake drum temperature model,it is more effective to evaluate the safety of the four sections above the Luoluan Expressway in Henan Province and to put forward targeted and systematic safety safeguard measures,which can effectively prevent the traffic accidents of heavy trucks on long and downhill mountainous expressways.