Objective Question & Answer

Assertion (A) is true: A transition curve is introduced between a straight alignment and a

circular curve to gradually introduce centrifugal force. To ensure a smooth comfort level, the

curvature must increase at a uniform rate. Consequently, the rate of increase of curvature

must match the rate of increase of super-elevation so that the inner edge or center line can

be raisedproportionally.

Reason (R) is true: The fundamental purpose of fixing the length of a transition curve is to

ensure that the full super-elevation required for the circular curve is attained exactly at the

point wherethe transition curve ends and the circular curve begins (the tangent to spiral 

spiral to curve points).