Stopping Sight Distance On Level Ground With Breaking Efficiency Calculator

Stopping Sight Distance Formula:

\[ SSD = V_b \times t + \frac{V_b^2}{2 \times [g] \times f \times \eta_x} \]

Speed of Slow Moving Vehicle (Vb):

m/s

Break Reaction Time (t):

seconds

Design Coefficient of Friction (f):

Overall Efficiency from Shaft A to X (ηx):

Stopping Sight Distance (SSD):

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1. What is Stopping Sight Distance?

Stopping Sight Distance (SSD) is the minimum distance required for a vehicle to come to a complete stop safely when an obstacle appears on the road. It includes both the distance traveled during the driver's reaction time and the braking distance.

2. How Does the Calculator Work?

The calculator uses the Stopping Sight Distance formula:

\[ SSD = V_b \times t + \frac{V_b^2}{2 \times [g] \times f \times \eta_x} \]

Where:

\( V_b \) — Speed of slow moving vehicle (m/s)
\( t \) — Break reaction time (seconds)
\( [g] \) — Gravitational acceleration (9.80665 m/s²)
\( f \) — Design coefficient of friction
\( \eta_x \) — Overall efficiency from shaft A to X

Explanation: The first term represents the distance covered during reaction time, while the second term represents the braking distance considering friction and mechanical efficiency.

3. Importance of SSD Calculation

Details: Accurate SSD calculation is crucial for road design, traffic safety analysis, and determining safe driving speeds. It helps ensure that drivers have sufficient distance to stop safely when encountering obstacles.

4. Using the Calculator

Tips: Enter vehicle speed in m/s, reaction time in seconds, coefficient of friction, and mechanical efficiency. All values must be positive numbers with efficiency between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What factors affect stopping sight distance?
A: Vehicle speed, driver reaction time, road surface conditions (friction), vehicle braking efficiency, and road gradient.

Q2: How does speed affect stopping distance?
A: Stopping distance increases exponentially with speed - doubling the speed quadruples the braking distance.

Q3: What is typical reaction time for drivers?
A: Average reaction time is 2-3 seconds, but can vary based on age, alertness, and driving conditions.

Q4: How does road surface affect stopping distance?
A: Wet or icy surfaces significantly reduce friction coefficient, dramatically increasing stopping distance.

Q5: Why include mechanical efficiency in the calculation?
A: Mechanical efficiency accounts for energy losses in the braking system, providing a more realistic stopping distance.