Safety Evaluation Method And Practices Of Mountain Highways Long Downgrade

By the end of2011, the highway mileage of China has reached4.0802million km, andthe mountainous terrain accounted for about69%of the land area of China, and the mountainhighways accounted for a larger proportion of highways. The presence of many longdowngrade mountain highway segment due to topographical conditions, can easily madevehicle overspeed. Addition to the poor sight, and the unreasonable installation of safetyfacilities and other factors, accidents happened frequently, which endangered road safety. Theproportion of heavy trucks increased gradually with recent changes in traffic composition, andthe frequent traffic braking can easily caused brake failure when heavy vehicles traveled onlong downgrade, causing traffic accidents and losses. It really highlighted the importance oflong downgrade section of the road safety problem.Given the current situation of the accident rate of long downgrade in mountain highwayssegment and the heavy losses, this paper analyzed the safety impact factors of longdowngrade slopes proposed safety evaluation index, and introduced the safety indexcharacteristic values by data collection and collation. Then the paper established the longdowngrade slopes of mountain highways safety evaluation model and evaluation criteriacombined with the actual situation of China. The paper proposed reasonable set of hedge lane,traffic safety facilities, and enhancing traffic safety management improvement measures. Italso put forward brake failure vehicle speed model by using vehicle dynamics, trafficengineering, and on the basis of statistics, and then quantified the overloaded vehicle laneroad hedging setting method in terms of hedge lane position, horizontal alignment, andstructure to decrease the rate of loss of uncontrolled vehicle and to ensure the traffic safety byinstalling of signs, markings and protective facilities and safety improvement measures oflong downgrade section on mountain area provided from the aspects of education andmanagement. At last, this paper proposed remediation measures to improve the highwaysituation, to reduce the accident rate, and protect the highway operational efficiency by deeplystudying on the project of BaiLuo road in GuangXi province.The safety evaluation method and the remediation measures proposed in this paper gavea reference and basis about the potential safety problem of long or steep downgrade section ofhighways on mountain area all over the GuangXi province even though in China, which havehuge significance of promoting the safety level on mountain area, to decrease accident rateand ensure road operation.