The rate of equilibrium super-elevation on a road is1. Directly proportional to the square of vehicle velocity2. Inversely proportional to the radius of the horizontal curve3. Directly proportional to the square of the radius of the horizontal curveWhich of the above statements are correct?

• A. 1 and 2 only
• B. 1 and 3 only
• C. 2 and 3 only
• D. 1, 2 and 3