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Difficulty: EasyStopping Distance Components

A commercial driver operating a heavy vehicle equipped with air brakes is traveling at a speed of 40 mph40\text{ mph} on dry pavement. Under standard conditions, the stopping sequence consists of 103 ft103\text{ ft} of perception distance, 44 ft44\text{ ft} of reaction distance, 23 ft23\text{ ft} of air brake lag distance, and 110 ft110\text{ ft} of actual braking distance. What is the vehicle's total stopping distance in feet?

Answer: 280 ft

Answer

280 ft
For commercial vehicles equipped with air brakes, total stopping distance is the exact sum of four sequential components: Perception Distance (103 ft103\text{ ft}) + Reaction Distance (44 ft44\text{ ft}) + Brake Lag Distance (23 ft23\text{ ft}) + Braking Distance (110 ft110\text{ ft}) = 280 ft280\text{ ft}.

Step-by-Step Solution

1
Identify the four distinct physical components that comprise total stopping distance in an air-brake system.
The components are Perception Distance (103 ft103\text{ ft}), Reaction Distance (44 ft44\text{ ft}), Brake Lag Distance (23 ft23\text{ ft}), and Braking Distance (110 ft110\text{ ft}).
Air brake systems require accounting for mechanical brake lag in addition to human perception, human reaction, and mechanical braking.
2
Calculate the sum of all four distance components.
103+44+23+110=280 ft103 + 44 + 23 + 110 = 280\text{ ft}
Total stopping distance equals the total distance traveled from the initial hazard perception until the vehicle comes to a complete halt.

Key Concept

Air Brake Total Stopping Distance Formula
Estimated Time:45s
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Topics

Stopping Distance Components

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