Stopping distances in the Highway Code
Your stopping distance is the distance you travel while you react, plus the distance you travel while you brake.
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Thinking plus braking
If the car in front stops suddenly, you need time to notice, time to move your foot and time for the car to stop. The Highway Code splits this into two parts:
- Thinking distance: how far you travel before you start braking.
- Braking distance: how far you travel once you are braking.
Add the two together and you get the overall stopping distance. Rule 126 says never to get closer to the vehicle in front than this distance. It also says to drive at a speed that lets you stop well within the distance you can see to be clear.
The typical stopping distances chart
These are the figures from the Highway Code’s chart. It uses an average car length of 4 metres (13 feet).
| Speed | Thinking | Braking | Total | Car lengths |
|---|---|---|---|---|
| 20 mph | 6 m | 6 m | 12 m (40 ft) | 3 |
| 30 mph | 9 m | 14 m | 23 m (75 ft) | 6 |
| 40 mph | 12 m | 24 m | 36 m (118 ft) | 9 |
| 50 mph | 15 m | 38 m | 53 m (175 ft) | 13 |
| 60 mph | 18 m | 55 m | 73 m (240 ft) | 18 |
| 70 mph | 21 m | 75 m | 96 m (315 ft) | 24 |
Notice the pattern: thinking distance goes up by 3 metres for every 10 mph, but braking distance grows much faster. In the chart, the total at 70 mph is eight times the total at 20 mph.
It is a guide, not a promise
The chart itself says the distances are a general guide. The real distance depends on your attention, the road surface, the weather and the condition of your vehicle at the time.
Leave a bigger gap in bad weather
- Rule 126: allow at least a two-second gap between you and the vehicle in front on high-speed roads.
- The gap should be at least doubled on wet roads and up to ten times greater on icy roads.
- Rule 227: in wet weather, stopping distances will be at least double those on dry roads.
- Rule 230: in icy or snowy weather, stopping distances can be ten times greater than on dry roads.
A way to practise at home
Cover the “Total” column and add up thinking and braking for each speed. Then ask someone to call out a speed and answer in metres. Playing it as a race makes the numbers stick.
Quick check
At 30 mph, what is the typical overall stopping distance?
A. 9 metres · B. 14 metres · C. 23 metres
Show answer
C. 23 metres. 9 metres thinking plus 14 metres braking. Source: The Highway Code, rules 103 to 158 (Rule 126: stopping distances), GOV.UK
How many car lengths does the chart show at 70 mph?
A. 13 · B. 18 · C. 24
Show answer
C. 24. 96 metres is about twenty-four car lengths. Source: The Highway Code, rules 103 to 158 (Rule 126: stopping distances), GOV.UK
On a wet road, the gap to the vehicle in front should be:
A. the same as on a dry road · B. at least doubled · C. halved
Show answer
B. at least doubled. Rule 126 says at least doubled on wet roads. Source: The Highway Code, rules 103 to 158 (Rule 126: stopping distances), GOV.UK
Sources
- The Highway Code, rules 103 to 158 (Rule 126: stopping distances), GOV.UK
- Typical stopping distances (PDF), The Highway Code, GOV.UK
- The Highway Code, driving in adverse weather conditions (rules 226 to 237), GOV.UK
Contains public sector information licensed under the Open Government Licence v3.0.