Total Extra Widening required on Horizontal Curves Calculator

Extra Widening Formula:

\[ W_e = \frac{n \times l^2}{2 \times R_t} + \frac{v}{9.5 \times \sqrt{R_t}} \]

Number of Traffic Lanes:

Length of Wheel Base (IRC):

Radius of Curve:

Speed of Vehicle:

km/h

Tolerance:

Total Extra Widening: m

1. What is Total Extra Widening on Horizontal Curves?

Definition: Total extra widening on horizontal curves is the additional width required on curved sections of roads beyond the normal width of straight sections.

Purpose: It accounts for both mechanical widening (due to vehicle geometry) and psychological widening (for driver comfort and safety).

2. How Does the Calculator Work?

The calculator uses the formula:

\[ W_e = \frac{n \times l^2}{2 \times R_t} + \frac{v}{9.5 \times \sqrt{R_t}} \]

Where:

\( W_e \) — Total extra widening (meters)
\( n \) — Number of traffic lanes
\( l \) — Length of wheel base (meters, as per IRC)
\( R_t \) — Radius of curve (meters)
\( v \) — Speed of vehicle (km/h)

Explanation: The first term calculates mechanical widening, while the second term calculates psychological widening.

3. Importance of Extra Widening Calculation

Details: Proper widening ensures safe vehicle maneuverability, reduces accidents on curves, and improves overall road safety.

4. Using the Calculator

Tips: Enter the number of lanes, wheel base length, curve radius, vehicle speed, and optional tolerance percentage (±5%).

5. Frequently Asked Questions (FAQ)

Q1: What is mechanical widening?
A: The additional width required due to the off-tracking of vehicles as they navigate curves.

Q2: What is psychological widening?
A: Extra width provided for driver comfort, accounting for greater lateral clearance needs at higher speeds.

Q3: What's a typical wheel base length?
A: As per IRC, standard wheel base length is 6 meters for design vehicles.

Q4: When should I use the tolerance field?
A: Use it to add a safety margin (±5%) to account for construction variations or special conditions.

Q5: How does curve radius affect widening?
A: Smaller radii require significantly more widening than larger, gentler curves.