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New Hampshire driving lesson · Basic Driving

Stopping distance and following

A 2-minute lesson from the New Hampshire course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.

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Read time
2 minutes
Course unit
Basic Driving
Checkpoint questions
6
Source pages
23

Stopping takes longer than you think. Before the brakes even work, you have to notice the danger and move your foot. Speed multiplies the distance, which is why NH asks for a four-second gap.

Total stopping distance

The distance a vehicle travels, in ideal conditions, from the moment the driver realizes they must stop until the vehicle actually stops.

Handbook p. 23 ↗

What adds up to stopping distance

What adds up to stopping distance
PartWhat it isAverage
Perception timeRecognizing you must stop¾ second to 1 second
Reaction timeMoving foot from gas and starting to brake¾ second to 1 second
Braking distanceBrakes slow and stop the carAbout 158 ft at 50 mph, dry
Handbook p. 23 ↗

Know the rule

The faster you go, the more time and distance you need to stop. Doubling your speed makes stopping distance 4 times longer.

Handbook p. 23 ↗
4 times

Increase in stopping distance when speed doubles

Handbook p. 23 ↗
About 158 feet

Braking distance at 50 mph on dry pavement with good brakes

Handbook p. 23 ↗
4 seconds

Minimum following distance; closer is tailgating

Handbook p. 23 ↗

Know the rule

If someone tailgates you unsafely, find a safe place to pull over and let them pass.

Handbook p. 23 ↗

Know the rule

Following more closely than is reasonable and prudent is a violation of the law punishable by a fine.

Handbook p. 23 ↗

Put it into practice

You're doing 30 mph, then speed up to 60 mph. Your stopping distance isn't twice as long, it's about 4 times as long. Leave at least four seconds of space.

Check your understanding

Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.

By how much does stopping distance increase when a vehicle's speed doubles?
  1. 8 times
  2. 2 times
  3. 4 times
  4. 3 times

Answer: 4 times

Stopping distance increases 4 times when speed is doubled.

Handbook p. 23 ↗
What is the average perception time for an alert driver, according to the manual?
  1. 1/4 second
  2. 2 to 3 seconds
  3. 4 to 5 seconds
  4. 3/4 second to 1 second

Answer: 3/4 second to 1 second

Average perception time for an alert driver is 3/4 to 1 second.

Handbook p. 23 ↗
At 50 mph on dry pavement with good brakes, about how long is a car's braking distance?
  1. About 335 feet
  2. About 100 feet
  3. About 158 feet
  4. About 250 feet

Answer: About 158 feet

At 50 mph on dry pavement, it can take about 158 feet to stop.

Handbook p. 23 ↗
What minimum following distance should drivers maintain to avoid tailgating?
  1. One second
  2. Four seconds
  3. Six seconds
  4. Two seconds

Answer: Four seconds

Drivers should avoid following closer than a four-second gap.

Handbook p. 23 ↗
The average driver's reaction time, moving the foot from gas to brake, is about 2 to 3 seconds.
  1. True
  2. False

Answer: False

The average driver's reaction time is 3/4 second to 1 second.

Handbook p. 23 ↗
The faster a vehicle travels, the more time and distance are needed to stop it.
  1. True
  2. False

Answer: True

Higher speed increases both the time and distance needed to stop.

Handbook p. 23 ↗
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