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Missouri driving lesson · Safe Driving Basics

Stopping distance

A 2-minute lesson from the Missouri 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
Safe Driving Basics
Checkpoint questions
6
Source pages
60

Stopping takes more room than most drivers expect. Your total stopping distance is your reaction distance plus your braking distance, and driving fast, being very tired or having bad brakes makes it longer.

Reaction distance

The distance you travel after you see a danger and before you apply the brakes. The handbook's chart assumes 1.5 seconds.

Handbook p. 60 ↗

Braking distance

The distance you travel after you apply the brakes until you stop. The chart assumes good brakes and tires, good weather and a good road.

Handbook p. 60 ↗

Know the rule

Stopping distance = reaction distance + braking distance.

Handbook p. 60 ↗

Know the rule

If you're driving fast, very tired, or your brakes are bad, you need more space to stop.

Handbook p. 60 ↗
1.5 seconds

Reaction time used in the handbook's stopping chart; you must be alert to react this fast

Handbook p. 60 ↗

Average stopping distance, cars on dry level pavement

Average stopping distance, cars on dry level pavement
SpeedReaction (ft)Braking (ft)Total (ft)
20 mph441862
30 mph6640106
45 mph10090190
55 mph121134255
60 mph132160292
65 mph143188331
80 mph176284460
Handbook p. 60 ↗

Put it into practice

At 55 mph you travel 121 feet before your foot even reaches the brake, then 134 more feet while braking: 255 feet in all. At 30 mph, the total is just 106 feet.

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.

What two components make up your total stopping distance?
  1. Reaction plus following distance
  2. Following distance plus signal time
  3. Vision distance plus headlight range
  4. Reaction plus braking distance

Answer: Reaction plus braking distance

Stopping distance equals your reaction distance plus your braking distance.

Handbook p. 60 ↗
What is 'reaction distance'?
  1. Distance traveled before you brake
  2. Distance traveled while braking
  3. Space between you and the car ahead
  4. Total distance to a full stop

Answer: Distance traveled before you brake

Reaction distance is the distance you travel after seeing a danger and before applying the brakes.

Handbook p. 60 ↗
What is 'braking distance'?
  1. Distance traveled before you brake
  2. Distance traveled while braking to a stop
  3. Distance to the vehicle ahead
  4. Reaction plus braking distance

Answer: Distance traveled while braking to a stop

Braking distance is the distance traveled after you apply the brakes and before the vehicle comes to a complete stop.

Handbook p. 60 ↗
In the handbook's stopping distance chart, what reaction time is assumed for the reaction distance figures?
  1. 0.5 seconds
  2. 1.0 seconds
  3. 1.5 seconds
  4. 2.5 seconds

Answer: 1.5 seconds

The reaction distance figures in the chart are based on a reaction time of 1.5 seconds.

Handbook p. 60 ↗
Which factor listed in the handbook increases the space you need to stop your vehicle?
  1. Driving slower than the posted limit
  2. Using cruise control on a dry highway
  3. Keeping your tires properly inflated
  4. Driving fast, fatigue, or bad brakes

Answer: Driving fast, fatigue, or bad brakes

If you are driving fast, are very tired, or your vehicle has bad brakes, you will need more space to stop.

Handbook p. 60 ↗
Braking distance figures in the handbook's chart assume good brakes and tires, in good weather, on a good road.
  1. True
  2. False

Answer: True

The braking distance chart is based on a vehicle with good brakes and tires, in good weather, on a good road.

Handbook p. 60 ↗
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