Which of the following curves is usually NOT adopted for transitioning in horizontal alignment?

Option 4 : Reverse

Transition curve is provided to change the horizontal alignment from straight to circular curve gradually and has a radius which decreases from infinity at the straight end (tangent point) to the desired radius of the circular curve at the other end (curve point). Cubic parabola, spiral and Lemniscate are typically used as transition curves.

There are five objectives for providing transition curve and are given below:

1. to introduce gradually the centrifugal force between the tangent point and the beginning of the circular curve, avoiding sudden jerk on the vehicle. This increases the comfort of passengers.

2. to enable the driver turn the steering gradually for his own comfort and security,

3. to provide gradual introduction of super elevation, and

4. to provide gradual introduction of extra widening.