Which two distances comprise the total stopping distance?

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

Answer: (A)

The total stopping distance is made up of two parts: the distance you travel during your reaction time after recognizing a hazard, and the distance you travel while your brakes are applying until you come to a stop. The first part is called the reaction distance, and the second is the braking distance. Add those two together and you get the total stopping distance.

Why the other ideas don’t fit here: perception distance covers the time and road you travel while you’re recognizing the hazard, and in this framework that is already encompassed in the reaction phase. Pairing perception with braking leaves out the movement that happens during the reaction time. Including braking distance with stopping distance would be circular, since stopping distance already includes braking. And leaving out braking misses the distance covered once you start braking.