Purpose and benefits of superelevation on horizontal curves What is the principal advantage of providing superelevation (transverse slope) on roads?

Introduction / Context:
Superelevation is the inward cross slope provided on curves to balance lateral acceleration. It improves vehicle stability, reduces side friction demand, and aids drainage and durability of the pavement.

Given Data / Assumptions:

• Two-lane or multilane roadway with standard superelevation up to permissible maximum (commonly around 7–10% depending on jurisdiction).
• Traffic operating near design speed.

Concept / Approach:
By banking the pavement, the component of weight helps counteract centrifugal effect. This allows higher safe speeds, lowers lateral friction and tire wear, and reduces edge damage. The slope also expedites drainage, decreasing water-film thickness and associated skid risks, indirectly lowering maintenance.

Step-by-Step Solution:
Superelevation reduces lateral acceleration demand → higher safe speed.Lower distress from skidding/edge breakdown → reduced maintenance costs.Cross fall accelerates runoff → improved drainage.Stable operation at higher speeds → higher effective capacity for the curve section.

Verification / Alternative check:
Speed–superelevation–friction relationships (e.g., v^2/(225 R) ≈ e + f) show how e reduces reliance on side friction at a given speed.

Why Other Options Are Wrong:
Each single option captures only part of the benefits; the comprehensive answer is that all apply.

Common Pitfalls:
Assuming superelevation is purely for speed; drainage and durability benefits are significant as well.

Final Answer:
All the above