The objective of providing a transition curve on the approach to horizontal curves in order to

Explanation:

Transition curve:

• Transition curve has radius which decreases from infinity at the tangent point to a designed radius of the circular curve.
• lf a curve of radius ‘r’ takes off from straight road and a vehicle travels on this road then due to the centrifugal force which suddenly acts on the vehicle just after the tangent point, a sudden jerk is felt on the vehicle.
• This not only causes discomfort to the passengers but also makes it difficult to street the vehicle safely.
• If a transition curve is introduced between the straight and circular curve of radius ‘R’ the centrifugal force will also introduce gradually as the radius of the transition curve decreases from infinity.
• The rate at which this force is introduced can be controlled by adopting suitable shape of the transition curve and by designing its length so that vehicle can have a smooth entry from the straight to the circular curve at the design speed.