The Study On The Driving Safty Of The Heavy Commercial Vehicles On The Continuous Long And Steep Downgrade Of The Moutian Highway

To design the vertical alignment of high way in mountain areas of western China, we have to adopt the continuous downhill because of some limitations, such as the geological, topographical limitation, construction cost and other conditions. Some downhill roads can reach several kilometers or even dozens of kilometers,which are called continuous long and steep downgrade.Of all the traffic accidents, the number of those happened in continuous long and steep downgrade in highway is several times or even ten times of those in straight highway, and most of those accidents were caused by heavy commercial vehicles, especially heavy load and overload ones. So it is very necessary to improve the traffic safety of the heavy commercial vehicles in the continuous long and steep downgrades.There was a typical continuous long and steep downgrade located between Yu'nan Province and Guangxi Province from Luocunkou to Funing,where a lot of traffic accidents often happen. When the vehicles traveled on the contious and long downhill the accident may happen because of braking failurely,so we proposed to control the speed of the heavy commercial vehicles to improve the traffic safety of the downhill.Through the road test,we studied the effect of the road hump on the driving comfort and safety of vehicles, and then got a hump which meets the driving requirement of the highway.Based on the study on the application of the compulsive speed control devices,we analyzed their effect.The study results provide a theoretical basis on how to improve the driving safety of the continuous long and steep downgrades in moutain areas,and has some practical significance for the commercial vehicles driving downhill safely.