Driver Sight Height given Length of Valley Curve Less than Stopping Sight Distance Calculator

Driver Sight Height Formula:

\[ h1 = \frac{(Ls-2 \times S) \times N + 2 \times S \times \tan(\alpha)}{2} \]

Length of Curve (Ls):

Sight Distance (S):

Deviation Angle (N):

rad

Inclination (α):

rad

Tolerance:

Driver Sight Height (h1):

1. What is Driver Sight Height?

Definition: Driver Sight Height refers to the vertical distance between the driver's eye level and the road surface while seated in a vehicle.

Purpose: It's crucial for determining visibility requirements in valley curve design to ensure safe stopping sight distance.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ h1 = \frac{(Ls-2 \times S) \times N + 2 \times S \times \tan(\alpha)}{2} \]

Where:

\( h1 \) — Driver Sight Height (meters)
\( Ls \) — Length of Curve (meters)
\( S \) — Sight Distance (meters)
\( N \) — Deviation Angle (radians)
\( \alpha \) — Inclination (radians)

Explanation: The formula calculates the driver's eye height considering the curve length, sight distance, and angular deviations.

3. Importance of Driver Sight Height Calculation

Details: Proper calculation ensures adequate visibility for drivers when approaching valley curves, preventing accidents and ensuring road safety standards.

4. Using the Calculator

Tips: Enter all required values in appropriate units. The tolerance field (default ±5%) allows for practical construction variations.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical driver sight height?
A: For passenger cars, it's typically 1.05-1.08 meters, while for trucks it's about 2.0-2.4 meters.

Q2: When is this formula applicable?
A: Specifically for valley curves where the length is less than the stopping sight distance.

Q3: How do I convert degrees to radians?
A: Multiply degrees by π/180 (approximately 0.0174533).

Q4: Why include a tolerance percentage?
A: It accounts for construction variations, vehicle differences, and measurement uncertainties.

Q5: What if my curve length exceeds sight distance?
A: A different formula applies for curves longer than the stopping sight distance.