UK Stopping Distances Explained (and How to Memorise Them)
Thinking distance, braking distance and total stopping distance — what they mean, when they appear in the test, and a trick to remember the numbers.
RC
Rob Cordina
Long-time UK driver and editor at PassTheory.live. Writes plain-English revision guides based on the current Highway Code and DVSA theory test syllabus.
Stopping distance questions come up in almost every theory test. Examiners want to know you understand the relationship between speed, reaction time and braking — not just that you have memorised a table.
The three components
- Thinking distance: how far you travel from spotting a hazard to pressing the brake. Roughly one foot per mph in good conditions.
- Braking distance: how far the car travels after the brakes are applied. Increases with the square of speed — doubling speed quadruples braking distance.
- Total stopping distance: thinking + braking, in metres.
The official numbers
- 20 mph — 12 metres (3 car lengths)
- 30 mph — 23 metres (6 car lengths)
- 40 mph — 36 metres (9 car lengths)
- 50 mph — 53 metres (13 car lengths)
- 60 mph — 73 metres (18 car lengths)
- 70 mph — 96 metres (24 car lengths)
A memory trick
Start with 20 mph = 12m. Then add 9, 13, 17, 20, 23 metres as you step up in 10 mph increments. The gaps grow because braking distance scales non-linearly with speed.
Wet and icy conditions
Double stopping distances in the wet. In ice, multiply by ten. Tyre tread and brake condition matter too — bald tyres in the rain can extend stopping distance beyond even the icy multiplier.