Driving at 55 mph on dry pavement, you need approximately how much distance to stop?

Driving at 55 mph on dry pavement, you need approximately how much distance to stop?

• A. The length of a football field
• B. Two football fields
• C. One city block
• D. Five car lengths

Answer: (A)

Stopping distance is the total of how far you travel while you perceive a hazard and react, plus how far you must coast while braking. At 55 mph on dry pavement, a typical driver takes about 1.5 seconds to react, which puts you roughly 120 feet behind the hazard before you start braking. The braking distance from 55 mph on dry pavement is commonly around 170 feet, so the total is near 290–300 feet. That total is about the length of a football field, so this option is the best match. The other choices are either too short or too long for this speed on dry pavement (five car lengths is far too short, and two football fields or a city block are longer than the usual stopping distance).

Stopping distance is the total of how far you travel while you perceive a hazard and react, plus how far you must coast while braking. At 55 mph on dry pavement, a typical driver takes about 1.5 seconds to react, which puts you roughly 120 feet behind the hazard before you start braking. The braking distance from 55 mph on dry pavement is commonly around 170 feet, so the total is near 290–300 feet. That total is about the length of a football field, so this option is the best match. The other choices are either too short or too long for this speed on dry pavement (five car lengths is far too short, and two football fields or a city block are longer than the usual stopping distance).