For the stopping distance at 55 mph, which choice is correct?

• A. Less than 200 feet
• B. About 400 feet
• C. More than 600 feet
• D. More than 400 feet

Answer: (D)

Stopping distance at 55 mph is the total distance your vehicle travels from the moment you decide to stop until you come to a complete stop. It combines two parts: the distance you cover during your reaction time (reaction distance) and the distance you travel while braking (braking distance). At 55 mph you’re moving about 80–85 feet per second. With a typical reaction time around 1.5 seconds, the reaction distance is roughly 120 feet. The braking distance on dry pavement for most vehicles at this speed is several hundred feet, often in the 300–360 feet range depending on conditions. Add those together and you’re commonly looking at about 420–480 feet.

Because the total stopping distance is over 400 feet, the correct choice is the one that says more than 400 feet. The other options underestimate the distance at this speed under typical conditions.