What is perception reaction distance (PRD)?

What is perception reaction distance (PRD)?

• A. The distance traveled during the perception reaction time
• B. The distance to the hazard plus reaction distance
• C. The distance after braking begins
• D. The sum of perception and reaction time

Answer: (A)

Perception reaction distance is the distance your vehicle covers from the moment you notice a hazard to the moment you begin to brake or take action. It equals speed multiplied by perception-reaction time, so it increases with faster speeds or longer reaction times. This distance is the first part of stopping distance, with braking distance following once braking starts. It’s not the distance to the hazard, not the distance after braking begins, and not a time value.

Perception reaction distance is the distance your vehicle covers from the moment you notice a hazard to the moment you begin to brake or take action. It equals speed multiplied by perception-reaction time, so it increases with faster speeds or longer reaction times. This distance is the first part of stopping distance, with braking distance following once braking starts. It’s not the distance to the hazard, not the distance after braking begins, and not a time value.