Stopping distances made simple | RAC Drive (2023)

A car’s stopping distance is an important part of any learner driver’s theory test –but it’s also something we all-too-soon forget.

Following too closely to other cars –or tailgating –is one of the biggest causes of road accidents in the UK and it could result in failing your driving test too.

Whether you're new to driving or have years of experience, knowing your stopping distances is a crucial part of staying safe on the roads, here we'll explain what they are, what affects them and how best to remember them.

What are average stopping distances?

It's first worth noting that a stopping distance = thinking distance + braking distance.

The following stopping distances relate to an average sized family car in normal weather conditions, however, it is also worth mentioning that a number of other factors can affect the stopping distance of a car (which we have outlined below).

Stopping distances made simple | RAC Drive (1)

Unsurprisingly, the faster a car is travelling, the longer it takes to stop.

Travelling at 40mph rather than 30mph means it’ll take an extra 13 metres (more than three car lengths) to come to a stop –think about that next time you consider breaking the 30mph speed limit.

Stopping distances are can be split into two main categories: the thinking distance and the braking distance.

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What is thinking distance?

Both categories are pretty self-explanatory. The ‘thinking distance’ is how long it takes for the driver to react to a hazard and apply the brake.

At higher speeds, the car will cover a greater distance while the driver realises he or she needs to brake to avoid a hazard. The Highway Code provides the following thinking distances at different speeds:

At motorway speeds, you could cover the length of four cars before you even apply the brakes.

There are a number of factors that could affect a driver’s thinking distance. We’ll come onto those shortly.

What is braking distance?

The second part of the overall stopping distance is made up of the braking distance. This is how far your car travels while you’ve got your foot on the brake attempting to bring it to an emergency stop.

These are the official braking distances provided by the Highway Code:

At 20mph, the braking distance is exactly the same as the thinking distance. These combine to provide a total stopping distance of 12 metres.

At 70mph, the 75-metre braking distance makes up nearly 80% of the overall 96-metre stopping distance.

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Techniques to remember stopping distances

Stopping distances are a favourite part of the theory test, but they’re not easy to remember. That’s unless you know a special trick...which we’ll reveal here.

It takes a bit of maths, but bear with us. All you need to do is multiply the speed by intervals of 0.5, starting with 2. That’ll give you the stopping distance in feet, which is acceptable for the theory test. For example…

20mph x 2 = 40 feet

30mph x 2.5 = 75 feet

40mph x 3 = 120 feet

50mph x 3.5 = 175 feet

60mph x 4 = 240 feet

70mph x 4.5 = 315 feet

There are 3.3 feet in a metre –so divide the distance in feet by 3.3 to get the stopping distance in metres. You’ll need a calculator for that, but it shouldn’t be necessary for the theory test.

How to practice for your driving theory test

There are a number of different ways topractice foryour driving theory test.

You can take free driving theory mock tests here on the officialGovernment site.

You can also brush up on your road signs knowledge on our very ownroad signs quiz page.

As for apps,Driving Theory Test UKis a great place to start, with all necessary learning materials, hazard perception clips and Highway Code info included. You can download it here:

Stopping distances made simple | RAC Drive (2)Stopping distances made simple | RAC Drive (3)

What other factors affect stopping distances?

As we’ve already mentioned, stopping distances can be influenced by a number of factors.

Some people suggest the stopping distances in the Highway Code are out of date because modern cars, with ABS systems and better tyres, can stop a lot quicker.

But remember, factors like this will only affect the braking distance. Unless the car’s fitted with an automatic emergency braking system, it won’t reduce the thinking time.

1. Weather

In poor weather conditions, a car’s total stopping distance is likely to be longer for a number of reasons. For a start, poor visibility might mean the driver takes longer to react –increasing his/her thinking distance. But slippery roads caused by rain, snow or ice will also extend the braking distance.

Research suggests braking distances can be doubled in wet conditions –and multiplied by 10 on snow or ice. That means, in the snow, it could take you further than the length of seven football pitches to stop from 70mph.

For help tackling the conditions check out our winter driving guide.

2. Road condition

It’s not always as obvious as ‘bad weather equals long stopping distances’, either. A road might be particularly greasy if there has been rain after a period of hot weather, or if oil has been spilt on it.

Be prepared for black ice on cold days, and watch out for loose surfaces such as gravel. All these could make it difficult to stop in a hurry.

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3. Driver condition

While all these factors can affect the braking distance, the individual behind the wheel is responsible for the thinking distance –and that can have a huge effect on the overall stopping distance.

A driver’s age, how awake they are and if they’ve consumed any drugs or alcohol can all influence how quickly it takes them to react.

Using a mobile phone rather than concentrating on the road can have devastating effects on a driver’s stopping distance –just a few seconds glancing at your phone can add an football pitch to your overall stopping distance at motorway speeds. If the traffic ahead has stopped, that could ruin your day very quickly.

Other distractions in the car –such as loud music and passengers –can also affect the thinking time before you apply the brakes.

4. Car condition

While many modern cars may indeed be able to stop in shorter distances than the official Highway Code states, a car’s condition can also have an impact.

For example, cars equipped with budget tyres can take an extra 14 metres to stop from 70mph in wet conditions compared to cars with ‘premium brand’ tyres, or five metres in the dry.

Research has also found that tyres on the legal limit of 1.6mm tread can need an extra 60% more road to stop compared to brand new tyres.

Under-inflated tyres will also have an impact on stopping distances, as will cars with poorly maintained brakes.

Click here to find out more about the importance of tyre health and a video on how to health check your tyres.

Check your brake pads to make sure they have plenty of life left in them, and test your brakes after driving through water to check for moisture left between the pads and discs.

For more on brake pads read our definitive guide to looking after your brake pads

Can my stopping distances affect my car insurance premium?

Indirectly yes. If you take out a black box car insurance policy it monitors how safely you drive. For example, information on your braking is collected. That data is then used to update your premium when you come to renew your insurance. If you’re deemed as less of a risk i.e. you have good braking habits, you could pay less.

For complete peace of mind at home and at the roadside, purchase RAC Breakdown Cover today.

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FAQs

Stopping distances made simple | RAC Drive? ›

All you need to do is multiply the speed by intervals of 0.5, starting with 2. That'll give you the stopping distance in feet, which is acceptable for the theory test.

Is there an easy way to remember stopping distances? ›

Overall Stopping Distance (on dry roads)

The factors are easy to remember - just start at 2 for 20mph and add 0.5 for each 10 mph increase in speed. Example: Question: What is the overall stopping distance at 50mph? Answer: Factor for 50mph is 3.5 and so overall stopping distance at 50mph is 50 x 3.5 = 175 feet.

What is the proper stopping distance when driving? ›

Time to Stop Your Car
SpeedPerception/Reaction DistanceBraking Distance
30 mph44 feet45 feet
40 mph59 feet80 feet
50 mph73 feet125 feet
60 mph88 feet180 feet
2 more rows

What is the formula for stopping distance? ›

To determine how far the vehicle will travel while braking, use the formula of 1/2 the initial velocity multiplied by the time required to stop.

What is stopping distance simple? ›

stopping distance = thinking distance + braking distance. This is when: thinking distance is the distance a vehicle travels in the time it takes for the driver to apply the brakes after realising they need to stop. braking distance is the distance a vehicle travels in the time after the driver has applied the brake.

What is the 4 second stopping distance rule? ›

To reduce the risk of collision, it's safest to stay 3-4 seconds behind the car in front of you. To measure this, pick a stationary object on the side of the road. Note when the car in front of you passes it, then count the seconds until you do.

What is the 5 second rule for distance? ›

If you drive faster than 40mph, it's a good idea to add an extra second for each 10mph of speed. For example, at 40mph, you should leave roughly five seconds of space between your vehicle and the vehicle in front of you. At 50mph, you may want to increase this to roughly seven seconds.

How many feet to stop at 55 mph? ›

At 55 mph, on a dry road with good brakes, your vehicle will skid approximately 170 feet more before stopping. This distance, combined with the perception and reaction distances, means you need about 300 feet to stop a car traveling at 55 mph. As a point of reference, Lambeau Field is 360 feet long, end to end.

Is the 3 second rule equal to the stopping distance? ›

California law requires you to maintain a safe traveling distance from the car in front of you regardless of how many seconds it takes to stop. Drivers should abide by speed limits and not follow other vehicles more closely than is “reasonable and prudent,” in the language of the law.

How many feet does it take to stop at 30 mph? ›

At 30 mph, the overall stopping distance is 75 feet.

What is the stopping distance at 70 mph? ›

Stopping distances at different speeds
SpeedThinking + braking distanceStopping distance
40mph12m + 24m36m (118 feet)
50mph15m + 38m53m (174 feet)
60mph18m + 55m73m (240 feet)
70mph21m + 75m96m (315 feet)
2 more rows
Aug 11, 2017

What are the 3 distances that make up total stopping distance? ›

Total Stopping Distance is the sum of the perception distance, reaction distance and braking distance. Once a driver perceives a need to slow or stop, a small amount of time passes.

What are the three things used to calculate stopping distance? ›

Stopping distance consists of three factors: Driver's reaction time + Brake lag + Braking distance.

What is the stopping distance at 25 mph? ›

One going 25 mph will cover about 55 feet of road during this time period. However, the time that it takes for the brakes to complete their job will increase at a more rapid rate. This is because the stopping distance is proportional to its mass times the square of its velocity.

How many car lengths is 2 seconds? ›

Assuming 60 mph which is 88 feet per second, 2 seconds is 176 feet. Assuming average US cars, like mid-sized sedans, 176 feet divided by 14.7 is 12 car lengths. Other sources suggest 15–16 feet is more like it. So really 10–12 car lengths.

Do you need to know stopping distances for theory test 2023? ›

You will notice from the Highway Code that there is an official chart included which clearly labels and details typical stopping distances. It's strongly recommended that you work on learning this chart, as it will help you with your theory test, should you be presented with a question about stopping distances.

Do you need to learn stopping distances? ›

Knowing your vehicle's stopping distance is an important part of passing your driving test, but it's also something that can be all too quickly forgotten in our day-to-day driving.

What are the 3 stopping distances? ›

Stopping distances at different speeds
SpeedThinking + braking distanceStopping distance
30mph9m + 14m23m (75 feet)
40mph12m + 24m36m (118 feet)
50mph15m + 38m53m (174 feet)
60mph18m + 55m73m (240 feet)
2 more rows
Aug 11, 2017

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