What does "super elevation" refer to in roadway design?

Super elevation refers specifically to the banking of a roadway at a curve, which is designed to counteract the effects of centrifugal force acting on a vehicle navigating that curve. By tilting the roadway, drivers experience a reduction in the lateral acceleration exerted on their vehicles, which enhances stability and reduces the risk of skidding or losing control, especially at higher speeds. This design feature is critical for improving safety on curves, as it allows vehicles to navigate turns more effectively and comfortably.

The other options do not accurately describe super elevation. A reduction in road elevation for drainage, for instance, addresses water management but does not involve the dynamic forces acting on vehicles. Improving visibility through elevation adjustments pertains more to line of sight concerns rather than curve navigation. Lastly, widening roads at turning points can aid maneuverability but is separate from the concept of super elevation, which specifically deals with the angle at which the roadway is banked for vehicles' stability.