A commercial driver operating an air brake-equipped vehicle observes an obstacle on the roadway and executes a complete emergency stop. Place the four sequential phases of total stopping distance in the correct chronological order from initial hazard observation to full vehicle rest.
- 1Perception distance: The vehicle travels while the driver sees, recognizes, and cognitively evaluates the roadway hazard.
- 2Reaction distance: The vehicle travels while the driver physically shifts their foot from the throttle to depress the brake pedal.
- 3Brake lag distance: The vehicle travels while air pressure flows through the lines and pushes the brake linings against the drums.
- 4Effective braking distance: The vehicle travels while friction between the brake linings and drums slows and stops the wheels.
Answer
The correct chronological sequence is: Perception distance, followed by Reaction distance, followed by Brake lag distance, and concluding with Effective braking distance.
The physical sequence of bringing an air brake commercial motor vehicle to a stop starts with cognitive perception of the hazard (perception distance), proceeds to the physical movement of the foot onto the brake pedal (reaction distance), followed by the time required for compressed air to actuate the brake shoes (brake lag distance), and concludes with the friction-based deceleration that brings the vehicle to zero speed (effective braking distance).
Step-by-Step Solution
Key Concept
Total stopping distance in air brake-equipped commercial vehicles is the cumulative sum of four sequential phases: perception distance, reaction distance, brake lag distance, and effective braking distance.
Estimated Time:1m 0s