Traffic Engineering MCQ with answer and solution

Concept

Definitions of traffic speed parameters

Formula

NONE

Step-by-step solution

1. Review fundamental traffic speed definitions: - Spot Speed: Instantaneous speed at a specific cross-section or point. - Running Speed: Average speed while vehicle is in motion (excluding stopped delay). - Travel Speed: Overall journey speed (total distance divided by total elapsed time including delays). - Average Speed: Mean speed of traffic stream (time mean or space mean speed). 2. The instantaneous speed at a specified cross-section is defined as Spot Speed. Answer: D

Explanation

Spot speed is defined as the instantaneous speed of a vehicle as it passes a specific point or transverse section of a highway. It is typically measured using an enoscope, pressure contact detectors, radar speed meter, or laser gun. In contrast, running speed is computed over a distance divided by moving time, while travel speed (journey speed) incorporates total travel time including all stopped delays.

Why the other options are wrong

A) Incorrect: Travel speed is measured over a route and includes all stopped delays. B) Incorrect: Average speed is a statistical aggregate over time or space. C) Incorrect: Running speed is measured over a stretch of road while the vehicle is in motion.

Shortcut

Instantaneous speed at a point = SPOT speed (measured at a single 'spot').

Common mistake

Confusing Spot Speed (instantaneous at a point) with Running Speed (measured over length excluding stops).