DVSA Speed and Stopping Distances 2 — Questions and Answers
Question 1: What is the overall stopping distance at 20 mph?
- 6 metres (20 feet)
- 12 metres (40 feet) (Correct answer)
- 23 metres (75 feet)
- 36 metres (120 feet)
Correct answer: 12 metres (40 feet)
At 20 mph, the overall stopping distance is approximately 12 metres (40 feet) — about 3 car lengths. This comprises 6 metres thinking distance and 6 metres braking distance.
Question 2: How does tiredness affect your stopping distance?
- It reduces braking distance
- It increases thinking distance because your reaction time is slower (Correct answer)
- It only affects braking distance
- It has no measurable effect
Correct answer: It increases thinking distance because your reaction time is slower
Tiredness slows your reaction time, which increases your thinking distance. A fatigued driver may take significantly longer to recognise a hazard and begin braking. Research shows tiredness can be as dangerous as drink-driving in terms of impaired reaction times.
Question 3: What is the 'two-second rule' and when should it be increased?
- Allow 2 seconds between seeing a hazard and braking — increase in fog
- Keep at least a 2-second gap between you and the vehicle ahead — increase to 4 seconds in wet conditions and more in ice/snow (Correct answer)
- Wait 2 seconds at every junction — increase at roundabouts
- Signal 2 seconds before turning — increase on motorways
Correct answer: Keep at least a 2-second gap between you and the vehicle ahead — increase to 4 seconds in wet conditions and more in ice/snow
The two-second rule means maintaining a gap of at least 2 seconds between you and the vehicle ahead in dry conditions. In rain, double it to 4 seconds. In ice and snow, allow up to 10 times the normal distance. Pick a fixed point and count the gap.
Question 4: At 50 mph, what is the approximate braking distance?
- 14 metres (45 feet)
- 24 metres (80 feet)
- 38 metres (125 feet) (Correct answer)
- 55 metres (180 feet)
Correct answer: 38 metres (125 feet)
At 50 mph, the braking distance is approximately 38 metres (125 feet). Combined with a thinking distance of 15 metres (50 feet), the overall stopping distance is about 53 metres (175 feet) — roughly 13 car lengths.
Question 5: How does alcohol affect stopping distance, even below the legal limit?
- It has no effect below the legal limit
- It increases thinking distance by impairing judgement, reaction time, and coordination (Correct answer)
- It only affects braking ability
- It improves confidence and has no negative effect
Correct answer: It increases thinking distance by impairing judgement, reaction time, and coordination
Even small amounts of alcohol impair your reaction time, judgement, and coordination, increasing thinking distance. Your ability to judge speed and distance is reduced, and you may take risks you would not normally take. The safest option is to avoid alcohol entirely if driving.
Question 6: What is the overall stopping distance at 40 mph?
- 23 metres (75 feet)
- 36 metres (120 feet) (Correct answer)
- 53 metres (175 feet)
- 73 metres (240 feet)
Correct answer: 36 metres (120 feet)
At 40 mph, the overall stopping distance is approximately 36 metres (120 feet) — about 9 car lengths. This comprises 12 metres thinking distance and 24 metres braking distance.
DVSA Speed and Stopping Distances 2
What is the overall stopping distance at 20 mph?