What are the types of curves in surveying?

Curves are provided to change the direction or alignment of road. Curves are the most important element in pavement design. They are provided with speed limits that must be strictly followed.
There are to main types of curve
1- Horizontal Curve
2- Vertical Curve

Horizontal curves are used to change the direction of road in a horizontal plane. They are of following types
* Simple Curve
* Compound Curve
* Reverse Curve
* Transition Curve
Vertical curves are used to make the road up and down.The types of vertical curves are
* Sag curve
* Summit curve