Technical Specifications of S-Type Compound Transition Curves in road construction

Definition of the S-Curve. In highway geometric design, the S-type curve (or reverse clothoid) is defined as a configuration consisting of two reverse clothoid transition curves without an intermediate tangent. These curves meet at a common point of contact, which serves as their shared origin, where the curvature is zero . In the present publication we present a simple method of computing sigmoid curves.