• (A) to obtain transition from the tangent to the circular curve and from the obtain transition from the tangent to the circular curve and from the circular to the tangent
• (B) to obtain a gradual increase of curfature from a value of zero at the tangent to a maximum at the circular curve
• (C) to have a gradual increase of super-elevation from zero at the tangent to a specific maximum at the circular curve
• (D) all of the above