What distance describes the movement from recognizing a hazard to starting braking?

• A. Reaction Distance
• B. Perception Distance
• C. Braking Distance
• D. Stopping Distance

Answer: (A)

The distance from recognizing a hazard to starting braking is the reaction distance. This is the portion of travel that occurs during the moment you process the danger and decide to brake, before the brakes are actually applied. It depends on your speed and your reaction time: Reaction distance = speed × reaction time. Perception distance, in contrast, is the distance traveled while you’re still recognizing the hazard, which happens before you decide to brake. Braking distance is the distance covered after you apply the brakes, and stopping distance is the sum of reaction and braking distances. So the term that matches the interval from recognition to brake activation is reaction distance.