The Highway Code gives typical stopping distances of 12 metres at 20 mph, 23 metres at 30 mph, 36 metres at 40 mph, 53 metres at 50 mph, 73 metres at 60 mph and 96 metres at 70 mph. In wet weather those distances will be at least double, and on ice or snow they can be ten times greater. The Code calls the figures a general guide, because your own distance depends on your attention, the road, the weather and your vehicle.
| Speed | Thinking | Braking | Total, dry road | Car lengths | Wet road, at least |
|---|---|---|---|---|---|
| 20 mph | 6 m | 6 m | 12 m (40 ft) | 3 | 24 m |
| 30 mph | 9 m | 14 m | 23 m (75 ft) | 6 | 46 m |
| 40 mph | 12 m | 24 m | 36 m (118 ft) | 9 | 72 m |
| 50 mph | 15 m | 38 m | 53 m (175 ft) | 13 | 106 m |
| 60 mph | 18 m | 55 m | 73 m (240 ft) | 18 | 146 m |
| 70 mph | 21 m | 75 m | 96 m (315 ft) | 24 | 192 m |
What are the stopping distances in the Highway Code?
The stopping distances in the Highway Code run from 12 metres (40 feet) at 20 mph to 96 metres (315 feet) at 70 mph, and each one is the sum of a thinking distance and a braking distance. The chart in the table above is the official one, with an average car length taken as 4 metres (13 feet).
Numbers are easier to picture as cars. At 30 mph you need about six car lengths to stop, and at 70 mph you need about twenty-four. It is worth remembering that the chart is a guide for dry conditions, so it shows what is typical, not what you should expect on a bad day. The Code says the distance will depend on these four things:
- your attention, which affects thinking distance
- the road surface
- the weather conditions
- the condition of your vehicle at the time
What is the difference between thinking distance and braking distance?
Thinking distance is how far you travel before you start to brake, and braking distance is how far you travel once you have. Add them together and you get the overall stopping distance.
What is thinking distance?
Thinking distance is the road you cover between seeing a hazard and pressing the brake. The chart gives 6 metres at 20 mph, 9 metres at 30 mph and 21 metres at 70 mph. If you work it out, those figures assume a reaction of about two-thirds of a second. Anything that takes your attention from the road makes that distance longer, and so does anything that dulls your reactions. Highway Code rule 95 says alcohol will slow down your reactions, and rule 91 says driving when you are tired greatly increases your risk of a collision. It recommends a break of at least 15 minutes after every two hours of driving.
What is braking distance?
Braking distance is the road you cover from the moment the brakes are applied until the car stops. The chart gives 6 metres at 20 mph, 14 metres at 30 mph and 75 metres at 70 mph. It depends heavily on the road surface, the weather and the condition of your vehicle. Tyres are the part you can check yourself: Annex 6 of the Highway Code says they must be correctly inflated, and cars and light vans must have a tread depth of at least 1.6 mm across the central three-quarters of the tread.
Why do stopping distances increase so quickly with speed?
Because thinking distance grows in step with your speed, but braking distance grows far faster. The chart shows the pattern clearly:
- From 20 mph to 40 mph, thinking distance doubles from 6 to 12 metres, while braking distance goes up four times, from 6 to 24 metres.
- From 30 mph to 60 mph, thinking distance doubles from 9 to 18 metres, while braking distance goes from 14 to 55 metres, about four times as far.
So twice the speed needs roughly four times the braking distance. That is one reason lower limits matter so much on busy streets, as our guide to 20 mph limits in Wales, London and elsewhere explains.
What is the stopping distance at 30, 40, 60 and 70 mph?
The typical stopping distance is 23 metres at 30 mph, 36 metres at 40 mph, 73 metres at 60 mph and 96 metres at 70 mph on a dry road. Here is how each one breaks down.
What is the stopping distance at 20 mph?
The stopping distance at 20 mph is 12 metres (40 feet), or three car lengths: 6 metres of thinking and 6 metres of braking.
What is the stopping distance at 30 mph?
The stopping distance at 30 mph is 23 metres (75 feet), or six car lengths: 9 metres of thinking and 14 metres of braking.
What is the stopping distance at 40 mph?
The stopping distance at 40 mph is 36 metres (118 feet), or nine car lengths: 12 metres of thinking and 24 metres of braking.
What is the stopping distance at 50 mph?
The stopping distance at 50 mph is 53 metres (175 feet), or thirteen car lengths: 15 metres of thinking and 38 metres of braking.
What is the stopping distance at 60 mph?
The stopping distance at 60 mph is 73 metres (240 feet), or eighteen car lengths: 18 metres of thinking and 55 metres of braking.
What is the stopping distance at 70 mph?
The stopping distance at 70 mph is 96 metres (315 feet), or twenty-four car lengths: 21 metres of thinking and 75 metres of braking. These are the limits you meet on the road, and our guide to the national speed limit in the UK shows which one applies where.
How much longer are stopping distances in the wet?
Stopping distances in the wet are at least double those on dry roads, because your tyres have less grip on the road. That comes straight from Highway Code rule 227, and "at least" is the important part. Double the chart and you get these minimum figures:
- At 30 mph, at least 46 metres.
- At 40 mph, at least 72 metres.
- At 60 mph, at least 146 metres.
- At 70 mph, at least 192 metres.
Rule 227 also has practical advice for rain:
- Keep well back from the vehicle in front, which also helps you see and plan ahead.
- Remember that rain and spray can make it hard to see and be seen.
- Be aware of spilt diesel, which makes the surface very slippery.
- Take extra care around pedestrians, cyclists, motorcyclists and horse riders.
What should you do if your steering feels light in the rain?
Ease off the accelerator and slow down gradually. Rule 227 says that if the steering becomes unresponsive, it probably means water is preventing the tyres from gripping the road.
Should you slow down in the rain?
Yes, whenever conditions call for it. Rule 125 says the speed limit is the absolute maximum and does not mean it is safe to drive at that speed whatever the conditions, and it tells you to reduce your speed when weather conditions make it safer to do so.
What is the stopping distance on ice and snow?
Stopping distances on ice and snow can be ten times greater than on dry roads, according to Highway Code rule 230. On that basis, the 23 metres you need at 30 mph on a dry road could become around 230 metres, which is why the Code asks you to keep well back from the road user in front.
The rules for winter driving are short and sensible:
- Rule 228: check the forecast and do not drive in icy or snowy conditions unless your journey is essential.
- Rule 229: you must be able to see, so clear all snow and ice from all your windows before you set off.
- Rule 230: drive with care even if the roads have been treated, and be prepared for conditions to change over relatively short distances.
- Rule 231: drive extremely carefully on icy roads and avoid sudden actions, as these could cause loss of control. Drive at a slow speed in as high a gear as possible.
Rule 231 includes a useful warning too: when travelling on ice, tyres make virtually no noise. If the road suddenly sounds quieter on a cold day, slow down gently.
What is the two-second rule?
The two-second rule means leaving at least a two-second gap between you and the vehicle in front on high-speed roads, and in tunnels where visibility is reduced. It comes from Highway Code rule 126, and it is the easy everyday version of a much longer rule: never get closer than the overall stopping distance.
- Pick a fixed point ahead, such as a bridge or a sign.
- When the vehicle in front passes it, count two seconds.
- If you reach the point before you finish counting, drop back.
What gap should you leave in the wet?
Rule 126 says the gap should be at least doubled on wet roads, so at least four seconds. On icy roads it should be up to ten times greater.
Do lorries and motorcycles need more room to stop?
Yes, rule 126 says large vehicles and motorcycles need a greater distance to stop. It also says a large vehicle in a tunnel should allow a four-second gap, and that if you have to stop in a tunnel you should leave at least a 5-metre gap to the vehicle in front.
How do you remember stopping distances?
The easiest way to remember the overall figures is a simple sum in feet. Multiply your speed by a number that goes up by a half each time, starting at 2 for 20 mph:
- 20 mph × 2 = 40 feet
- 30 mph × 2.5 = 75 feet
- 40 mph × 3 = 120 feet (the chart says 118)
- 50 mph × 3.5 = 175 feet
- 60 mph × 4 = 240 feet
- 70 mph × 4.5 = 315 feet
Thinking distance is easier still. In the chart, it is the same as your speed in feet: 30 feet at 30 mph, or 9 metres. For the metric figures, the car lengths are a handy shortcut: 3, 6, 9, 13, 18 and 24.
Are stopping distances accurate for modern cars?
Treat them as a guide rather than a measurement of your car. The Highway Code itself says the distances are a general guide, and it asks you to drive at a speed that lets you stop well within the distance you can see to be clear.
What do stopping distances mean for your next drive?
On your next trip, try the two-second count on a dry day and four seconds when it rains. Notice how much road that really is. Then match your speed to what you can see, because the road you can see to be clear is the road you have to stop in. Where limits change suddenly, such as smart motorways, that extra space gives you room to respond smoothly.
Ghost gives you extra time in a similar way. It warns you about known fixed speed cameras and average-speed zones about 700 m ahead and again at 250 m, with one tone and no voice, so you can check your speed early and calmly rather than at the last moment. It runs in the background next to any navigation app, works on CarPlay, Android Auto and Apple Watch, and covers more than 125,000 speed cameras worldwide. Rain or shine, it helps you stay relaxed and arrive safely.
