What is the term used to describe two curves that share a common tangent?

The term that describes two curves that share a common tangent is known as a reverse curve. In surveying and civil engineering, a reverse curve is characterized by two curves that connect in opposite directions, forming a smooth transition between them. This common tangent allows for a seamless flow of direction from one curve to the next, minimizing abrupt changes that could affect the stability and safety of the road or railway design.

Understanding reverse curves is crucial, especially in the context of road design where they are used to manage changes in direction while maintaining a continuous path for vehicles. The proper application of reverse curves can enhance the aesthetics of the roadway, as well as improve driver comfort and safety by allowing vehicles to navigate curves without sudden turns.