Curves to Change Direction or Alignment of a Road

There are several types of curves that are used in road design to change the direction or alignment of a road. These curves are designed to provide a smooth transition between straight sections of a road and improve safety for drivers. The following curves are commonly used for this purpose:

Sag Curve
A sag curve is a type of curve that is used to change the direction of a road by introducing a downward slope. It is called a sag curve because the road surface sags or drops down as the curve is approached. This curve is commonly used to transition from a straight section of road to a curve that is lower in elevation. The sag curve helps to maintain a smooth and continuous flow of traffic by allowing vehicles to gradually descend before entering the curve.

Summit Curve
A summit curve is a type of curve that is used to change the direction of a road by introducing an upward slope. It is called a summit curve because the road surface reaches its highest point at the curve. This curve is commonly used to transition from a straight section of road to a curve that is higher in elevation. The summit curve helps to maintain a smooth and continuous flow of traffic by allowing vehicles to gradually ascend before entering the curve.

Simple Curve
A simple curve is a type of curve that is used to change the direction of a road without introducing any significant changes in elevation. It is a smooth curve that connects two straight sections of road. The simple curve is commonly used in situations where the road does not need to change elevation significantly, such as in urban areas or on flat terrain. This curve helps to maintain a smooth and continuous flow of traffic by providing a gradual transition between straight sections of road.

All of the Above
All of the above curves are provided to change the direction or alignment of a road. Depending on the specific design requirements and the terrain, engineers may choose to use a sag curve, a summit curve, or a simple curve to transition between straight sections of road and curves. These curves help to improve safety and driver comfort by providing a smooth and gradual transition between different sections of the road.