Rate of Super Elevation Calculator

Super Elevation Formula:

\[ e = \frac{0.75 \times V^2}{g \times R} \]

Rate of Super Elevation:

1. What is Rate of Super Elevation?

Definition: Super elevation is the transverse slope along the width of the road provided by raising the outer edge of the road with respect to the inner edge, throughout the length of the horizontal curve.

Purpose: It helps counteract the centrifugal force on vehicles moving along curved paths, improving safety and comfort.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ e = \frac{0.75 \times V^2}{g \times R} \]

Where:

\( e \) — Rate of super elevation (ratio)
\( V \) — Velocity of vehicle (m/s)
\( g \) — Gravitational acceleration (9.80665 m/s²)
\( R \) — Mean radius of curve (meters)

Explanation: The formula calculates the required banking of the road to counteract centrifugal force at a given speed and curve radius.

3. Importance of Super Elevation

Details: Proper super elevation ensures vehicle stability, reduces side friction requirements, and improves safety on curved road sections.

4. Using the Calculator

Tips: Enter the vehicle velocity in m/s and the mean radius of the curve in meters. The result is shown as a percentage (e.g., 5% means 5 cm rise per meter of road width).

5. Frequently Asked Questions (FAQ)

Q1: What's the typical range for super elevation?
A: Usually between 2% to 10%, with maximum values depending on road type and climate conditions.

Q2: Why is the factor 0.75 used in the formula?
A: This accounts for the fact that not all centrifugal force needs to be counteracted by super elevation, with the remainder handled by tire friction.

Q3: How does velocity affect super elevation?
A: Super elevation increases with the square of velocity - double the speed requires four times the super elevation.

Q4: What's the practical maximum super elevation?
A: Typically 7-10% to prevent slow-moving vehicles from sliding inward during icy conditions.

Q5: How is super elevation implemented in road design?
A: It's gradually introduced along the transition curve before the main circular curve.