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Allowable Speed of Vehicle in Horizontal Curve Calculator

Allowable Speed Formula:

\[ v_a = \sqrt{0.22 \times g \times R_{mean}} \]

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1. What is Allowable Speed in Horizontal Curve?

Definition: The maximum safe speed a vehicle can maintain while navigating a horizontal curve without losing stability.

Purpose: Helps traffic engineers design safe roads and helps drivers understand safe speeds for curves.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ v_a = \sqrt{0.22 \times g \times R_{mean}} \]

Where:

  • \( v_a \) — Allowable speed (m/s)
  • \( g \) — Gravitational acceleration (9.80665 m/s²)
  • \( R_{mean} \) — Mean radius of the horizontal curve (m)

Explanation: The formula calculates the speed where centrifugal force is balanced by friction and superelevation.

3. Importance of Allowable Speed Calculation

Details: Proper speed calculation prevents accidents, reduces wear on vehicles, and ensures comfortable driving experience.

4. Using the Calculator

Tips: Enter the mean radius of the curve in meters and tolerance percentage (default 5%). All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the tolerance percentage for?
A: The tolerance accounts for safety margins, vehicle variations, and road conditions (default ±5%).

Q2: What's a typical mean radius for highway curves?
A: Highway curves typically range from 200m to 1000m radius, depending on design speed.

Q3: How does superelevation affect the calculation?
A: The 0.22 factor already accounts for typical superelevation (banking) of roads.

Q4: Can I use this for railway curves?
A: No, railway calculations use different formulas accounting for train dynamics.

Q5: How do I convert the result to km/h?
A: Multiply m/s result by 3.6 to get km/h (shown in the calculator).

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