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Difficulty: MediumStopping Distance Components

A commercial motor vehicle equipped with an air brake system is operating on a dry, level roadway. During a sudden stop, telemetry records a perception distance of 105 feet105\text{ feet}, a reaction distance of 45 feet45\text{ feet}, an air brake lag distance of 30 feet30\text{ feet}, and an effective braking distance of 180 feet180\text{ feet}. What is the total stopping distance in feet required for this vehicle to come to a complete stop?

Answer: 360 feet

Answer

360 feet
Total stopping distance for a commercial motor vehicle equipped with air brakes is the sum of four distinct components: perception distance (105 ft105\text{ ft}), reaction distance (45 ft45\text{ ft}), air brake lag distance (30 ft30\text{ ft}), and braking distance (180 ft180\text{ ft}). Summing these values yields 105+45+30+180=360 feet105 + 45 + 30 + 180 = 360\text{ feet}.

Step-by-Step Solution

1
Identify the formula for total stopping distance in an air-braked commercial vehicle.
Total Stopping Distance=Perception Distance+Reaction Distance+Brake Lag Distance+Braking Distance\text{Total Stopping Distance} = \text{Perception Distance} + \text{Reaction Distance} + \text{Brake Lag Distance} + \text{Braking Distance}
Air brake systems include mechanical air lag distance in addition to driver perception, driver reaction, and vehicle braking distance.
2
Substitute the provided component values into the formula.
105+45+30+180=360 feet105 + 45 + 30 + 180 = 360\text{ feet}
Adding all four discrete distance phases calculates the complete stopping distance from the moment the hazard is seen until the vehicle reaches zero velocity.

Key Concept

Four-component total stopping distance formula for air brake systems
Estimated Time:1m 0s
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Topics

Stopping Distance Components

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