Traffic Flow Characteristics MCQ with answer and solution

Concept

The fundamental relation of traffic stream flow states that Traffic Flow (q) = Traffic Density (k) × Traffic Speed (v).

Formula

q = k × v k = q / v

Step-by-step solution

1. Convert traffic speed from m/s to km/h: v = 12.5 m/s × 3.6 = 45 km/h 2. Use the fundamental traffic relationship k = q / v: k = 920 veh/h / 45 km/h = 20.44 veh/km 3. Select the closest option: 20.4 veh/km.

Explanation

Traffic density is calculated using the fundamental relation of traffic flow, q = k × v, where q is traffic flow rate, k is traffic density, and v is space mean speed. Converting speed from m/s to km/h gives v = 12.5 × 3.6 = 45 km/h. Dividing the flow rate (920 veh/h) by the speed (45 km/h) yields a traffic density of 20.44 veh/km, which rounds to 20.4 veh/km.

Why the other options are wrong

A: Incorrect value due to calculation error. B: Incorrect value due to calculation error. C: Incorrect value resulting from misapplying speed conversion.

Shortcut

Divide flow directly by (speed in m/s × 3.6): 920 / (12.5 × 3.6) = 20.44 veh/km.

Common mistake

Dividing 920 directly by 12.5 without converting m/s to km/h, which gives an incorrect density.