What term is used to describe a straight segment connecting two curves in a road?

The term used to describe a straight segment connecting two curves in a road is "tangent." In roadway design, the tangent refers to a straight line that transitions between curves, providing a smooth connection and ensuring safe vehicle maneuverability. This segment is essential for maintaining a consistent driving path and enhancing visibility for drivers as they approach the curves.

In a typical road alignment, the tangent section serves to eliminate abrupt changes in alignment that could lead to unsafe conditions. It allows drivers to adapt to changes in curvature without sudden steering adjustments, thereby improving driving comfort and safety.

The other terms do not accurately describe this concept. A curve refers to the circular segment itself, while a span usually refers to the distance between two supports, often used in the context of structures rather than roadway alignments. Linear often describes a straight path in a general sense but does not specifically relate to the transition between curves in road design. Therefore, "tangent" is the most appropriate term for this straight segment in the context of road geometry.