Abstract:According to the accident investigation data, the accident rate of honghuawan hub interchange on the small radius ramp is significantly higher than that of other locations. Vehicles often collide with the waveform beam guardrails outside the curve and occasionally the truck rolls over. In order to study the cause of the accident here, the vehicle dynamics software CarSim and TruckSim were used to conduct experimental analysis under different simulation conditions, and the influencing factors of vehicle sideslip and rollover on the small radius ramp and the formation mechanism of the accident were obtained. The research results show that: (1) The driving speed of the small passenger car has a significant effect on the driving stability of the small radius ramp, and the lateral offset and driver comfort are significant. When the ramp radius value is 60 ~ 65m, in order to ensure the safety and comfort of the curve Sex, the speed should not exceed 50km / h; (2) In order to ensure driving safety, the long line segment should be set to the long line segment before the radius ramp curve, and the length of the sliding track is guaranteed; (3) The larger the speed, the road surface The smaller the adhesion coefficient, the more serious the side slip of the vehicle, and the color anti-skid pavement should be added to the vertical turnover to improve the pavement attachment coefficient in this vertical turn. (4) When the speed limit value is 40km/h, the tire load transfer rate is the smallest. The tire load transfer rate decreases with the increase of road superelevation and road adhesion coefficient, and increases with the increase of load and center of mass height.