What are two circular curves lying on opposite sides of a common tangent called?

Two circular curves lying on opposite sides of a common tangent are known as reverse curves. This terminology is used in surveying and civil engineering to describe a specific arrangement of curves that change direction. Reverse curves are characterized by their positioning, as they typically face in opposite directions, creating a smooth transition between two straight segments of a road or railway.

The significance of reverse curves lies in their ability to help vehicle dynamics by allowing smoother navigation through changes in alignment without the abruptness that would be present if the curves were sharp or had a significant angle. This design feature enhances safety and comfort for drivers, as the gentle transition helps maintain speed and control.

In contrast, concentric curves occur when multiple curves share the same center point but have different radii, which is not applicable here. Compound curves involve a series of curves that are connected and have different radii but do not necessarily change directions between the curves. Simple curves refer to individual curves without adjacent curves impacting their layout, making reverse curves the correct identification for the scenario described.