Research On Traffic Safety Analysis And Evaluation Of Long And Steep Downgrade Sections In Qinghai

Long and steep downgrade sections are often black-spots. It has great relationship between accident's happen on continuous downgrade and longitudinal grade and length. Long-distance downgrade always cause that the car is over speed and the brake is out of control.Analyzing the serious traffic accidents on the freeway of Huangyuan to Daotanghe in Qinghai, this paper regards the operating speed as a medium to discover the relationship between accident and freeway alignment. Firstly, this paper studies the change of operating speed in this long downgrade sections, analyzes the main reason that affect the operating speed in the sections. So the paper establishes the model between the operating speed on continuous long and steep downgrade sections and downgrade gradient, the distance from the top of the slope. And it also gives some advices on how to control speed when the vehicle is often over speed on these sections.Secondly, this paper brings forward logical grade length of various grade of slope by adopting the model between the brake temperature of on continuous long and steep downgrade sections and downgrade gradient,the distance from the top of the slope, the truck operating speed on long and steep downgrade sections and the weight of vehicle.Lastly, with the principal component cluster analysis method of statistics, the paper studies the present state and the evaluation methods of the traffic accidents both in china and abroad, constructs the system of synthesis evaluation of long and steep downgrade sections traffic safety. The new indicators used in the road traffic accidents occurred on the long and steep downgrade sections of the freeway of Huangyuan to Daotanghe. With these indications, this paper has a simple and clear conclusion and reflects a true character of the traffic safety and traffic accidents.