| Analyzing the domestic and overseas' serious traffic accidents, this paper have roundly and systematically researched traffic accidents on the road with the longer and steeper downgrade in Yunan ,and study and draw lessons of road traffic safety evaluation technology from the domestic and overseas.Through choosing the typical longer downgrade section in Yunan— the freeway of Songming to Daibu and Yuxi to Yuanjiang to Mohei as the research objects. Roundly and statistically analysis accidents' situation, and adopt the cluster analytical method to statistically analyse the time of accidents, the serious road section of accidents, the form of accidents ,and have analysed the cause of accidents on the road with longer downgrade.Educe the relationship between accidents' happen on continuous downgrade and longitudinal grade and length ,long-distance downgrade is the main reason of inducing traffic accidents, correlative statistic indicate accidents of sixty perent have the relation with good-sized and medium-sized vehicle especial burden, overfreight vehicle's brake that fail to work on the bottom of slope section.When good-sized and medium-sized vehicle travel on the downgrade, the brake continuously do heavy intensity arrestment for a long time, which make brake temperature rise quickly, and burden and overfreight vehicle even though have seldom arrestment, also can make brake temperature rise rapidly, appear the phenomenon of heat decline, so the brake is out of control and lead to accidents.To the cause of accidents, put forward to set up avoid dangerous lane to solve the longer and steeper downgrade section that has many accidents in Yunan. Through setting up avoid dangerous lane make the out of control vehicle that have broken brakes(especial burden auto) bear off the main lane, and safely decelerate to stop in the avoid dangerous lane, which avoid great casualties and property loss.This paper has researched the main reasons and the characteristics of traffic accidents that caused many heavy deaths, injuries and property loss. Cluster analysis has been applied to distinguish the accidents severity in this paper and it has discussed with the traffic accident contributing factors about the heavy vehicle that brake is ineffective or failure. Then it probes into the methods of decrease in traffic accidents through setting up emergency escaping lane. And the paper researched the design parameter of emergency escaping lane including of intersection angle, length, materials, locale and traffic signs depending on the auto dynamics simulation of threekinds of heavy trucks. The paper discussed the mountainous long downhill highway traffic audit methods and get the conclusion that intersection angle between the emergency escaping lane and driving lane should be less than 11°, the max angle do not exceed 15° for the vehicle out of control gets into escaping lane in safety.In addition, thesis expound the effective measure ,which is to set up person who serve , parking zone and add water .According to the road traffic accident distribution characteristic of long downhill path, the thesis has carried on the discussion to the road security appraisal technology of the downhill path of head of district of mountain, and has analysed to the safety engineering measure validity of the road, in order to promote the improvement , perfection of the safety measure, guarantee road's security finally. |
