The Open Door Web Site  
Mechanics Banking of a Road Surface
Moving
in a Straight line on a Horizontal Surface
Turning on a Horizontal Surface
Turning on a Banked Surface
Angle of Banking The magnitude of the horizontal component of the normal reaction is
This force causes the centripetal acceleration, so, the magnitude of R_{H} is also given by
So,
The vertical forces acting on the vehicle are in equilibrium. Therefore, considering magnitudes only
Dividing equation 1 by equation 2 gives:
This equation allows us to calculate the angle needed for a vehicle to go round the curve at a given speed, v, without any tendency to skid. 
