The 20th and 21st joint COTA International Conference of Transportation Professionals (CICTP 2020-21)

In order to ensure the safe driving of vehicles on dedicated ramps, and to make full and effective use of road resources, this paper studies the super-elevation of dedicated ramps for passenger cars. The article mainly adopts the method of mechanical analysis and calculation, and refers to the setting of the maximum super-elevation of passenger car and truck mixed roads recommended in the "Technical Standards of Highway Engineering" and "Guidelines for Design of Highway Grade-separated Intersection", and also considers the separation of passenger car and truck roads’ actual characteristics. Firstly, from the aspects of driving safety, comfort, environment, construction and traffic composition., it is proposed that the maximum super-elevation of the dedicated ramp for passenger cars in non-ice and snow conditions should be 10%, and the maximum in the snow and ice environment should be 8%. Secondly, the advantages and disadvantages of the point mass-rigid body calculation model (PMR) and the point mass-suspension calculation model (PMS) are analyzed and compared. Thirdly, considering the situation of the over speed of vehicles on the dedicated ramps and safety, the AASHTO recommended super-elevation and sideway force coefficient distribution model is optimized and improved, and this paper proposes a new model of super-elevation and sideway force coefficient distribution based on dangerous speed. This model can guarantee the sideway stability of passenger cars at a low-speed or normal-speed. Finally, according to the new allocation model, this paper proposes the recommended super-elevation of different design speeds and radius for the dedicated ramps for passenger cars.

CICTP