Highway Engineering — Superelevation Terminology The slope provided on a road surface at horizontal curves to counteract centrifugal effects is called the:

Introduction / Context: Vehicles negotiating a horizontal curve experience lateral acceleration. Roads are raised on the outer edge (banked) to develop a component of normal reaction that supplies the necessary centripetal force, improving safety and comfort.

Given Data / Assumptions:

• Highway curve with designed speed and radius.
• Uniform cross slope (superelevation) on the curve.

Concept / Approach: Banking (superelevation) tilts the pavement at an angle so that part of the weight’s normal reaction provides inward radial force. The “angle of banking” or the corresponding superelevation rate e is set by speed, radius, and side friction allowance.

Step-by-Step Reasoning:

Verification / Alternative check: Standards specify e = v^2 / (g r) (basic form without side friction) for design checks, confirming the role of banking.

Why Other Options Are Wrong: Angle of friction is related to μ and impending slip; angle of repose is for granular piles and sliding initiation, not road design; “none” is incorrect.

Common Pitfalls: Confusing banking with camber (for drainage); mixing angle units with the superelevation rate e.

Final Answer: Angle of banking (superelevation).