Fundamentals of Surveying (FS) Practice Exam

Highway curves are most often which type of arcs?

1. Elliptical

2. Spiral

3. Circular

4. Flat

The correct answer is: Circular

Highway curves are most often circular arcs because they provide continuous and uniform changes in direction for vehicles, ensuring safe and efficient navigation along the roadway. Circular arcs facilitate smoother transitions and help maintain vehicle stability at varying speeds, which is crucial for road design and safety. In transportation engineering, circular curves are easier to design, construct, and maintain compared to other types of curves. Their geometric properties allow for consistent calculations related to sight distance, superelevation, and lateral friction, which are important for the comfort and safety of drivers. Other forms of arcs, such as elliptical or flat arcs, are less common in highway design because they do not provide the same level of predictability or ease of vehicle maneuverability. Spiral curves, while also used in some cases, primarily serve as a transition between straight and circular sections rather than as the main form of the highway curve. Thus, the preference for circular arcs in highway design stems from their straightforward application and the safety benefits they offer.