Time given Length of Valley Curve and Design Speed Calculator

Time Formula:

\[ t = \frac{L_s}{v} \]

Time (seconds):

1. What is Time given Length of Valley Curve and Design Speed?

Definition: This calculator computes the time it takes for a vehicle to traverse a valley curve based on the curve length and design speed.

Purpose: It helps transportation engineers and road designers determine travel time through vertical curves.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ t = \frac{L_s}{v} \]

Where:

\( t \) — Time (seconds)
\( L_s \) — Length of valley curve (meters)
\( v \) — Design speed (meters/second)

Explanation: The time is calculated by dividing the curve length by the design speed.

3. Importance of Time Calculation

Details: Accurate time calculation ensures proper vertical curve design for safety and comfort, accounting for driver perception-reaction time.

4. Using the Calculator

Tips: Enter the length of curve in meters (±5%) and design speed in m/s (±5%). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the ±5% tolerance included?
A: It accounts for variations in actual vehicle speeds and slight differences in curve implementation.

Q2: How does this relate to driver comfort?
A: Proper time calculation ensures the curve length provides adequate transition time for comfortable vertical acceleration changes.

Q3: What's a typical design speed for valley curves?
A: Design speeds vary by road type, typically ranging from 20 m/s (45 mph) for local roads to 35 m/s (80 mph) for highways.

Q4: How do I convert between m/s and mph?
A: 1 m/s ≈ 2.237 mph. For mph to m/s, multiply by 0.447.

Q5: Does this consider acceleration/deceleration?
A: No, this assumes constant speed. For varying speeds, more complex calculations are needed.