Stopping distances and the Theory Test

Understanding stopping distances as part of your Theory Test can be one of the more difficult areas to learn. We’re here to guide you through this often complex section.

Are you preparing for your UK Driving Theory Test but keep getting caught out by the questions on stopping distances, braking distance and thinking distance?

If so, check out the information below which will explain the differences and help you remember the correct stopping distances so you’re not left confused and panicking on the day of your Theory Test!

Once you’ve read the guide, why not test your knowledge with our unique Stopping Distance 3D Simulator; designed to help you master one of the most difficult areas of the driving Theory Test.

So what are the differences between the thinking distance, braking distance and stopping distance?


What is thinking distance?

Thinking distance is the distance travelled between the time the need to brake is realised, and the time it takes to activate the brakes.

TIP: thinking distance is approximately 1 foot for every mph you are travelling at.

So for example, if you are travelling at 30mph then your thinking distance is approximately 30 feet.

What is braking distance?

Braking distance is the distance your car travels after you have applied the brakes until your vehicle comes to a stop. The faster you are travelling, the more momentum you have and the braking distance will increase.

What is stopping distance?

Stopping distance is the total distance you travel before you apply the brakes, plus the distance you travel while the brakes slow you down.

Thinking distance+ braking distance = overall stopping distance.

It’s worth noting that the estimated stopping distance formula is based on the driver not being distracted or impaired, driving a well-maintained vehicle, and normal, dry road conditions.

The stopping distance formula is best described in this image:

stopping distance formula

The distances shown are a general guide. The distance will depend on your attention (thinking distance), the road surface, the weather conditions and the condition of your vehicle at the time.
(Average car length = 4 metres (13 feet)

How to remember the stopping distance formula

TIP: Here is a great way to remember the overall stopping distances.

Starting from 20mph you simply multiply the speed by intervals of 0.5, beginning with 2, for example, 2, 2.5, 3, 3.5 etc., as follows:

20 mph x 2 = 40 feet ((12 meters) or 3 car lengths)
30 mph x 2.5 = 75 feet ((23 meters) or 6 car lengths)
40 mph x 3 = 120 feet ((36.5 meters) or 9 car lengths)
50 mph x 3.5 = 175 feet ((53 meters) or 13 car lengths)
60 mph x 4 = 240 feet ((73 meters) or 18 car lengths)
70 mph x 4.5 = 315 feet ((96 meters) or 24 car lengths)

The above calculations are a simple way to help you remember the correct stopping distances, but please be aware that these are approximate.

The overall stopping distance is really the only safe separation gap; anything less than this can be considered a risk.

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What affects overall stopping distances?

You must always remember that the overall stopping distance of your vehicle depends greatly on a considerable number of factors including:

  • How fast you are travelling. If you’re travelling at a high speed, you’ll have to leave more time to brake.
  • Whether you are on a level road, or a hill going up or down, and the steepness of that hill.
  • Weather; is it good and dry, or is it wet or icy
  • Tyres; are they good tyres and properly inflated, or worn or badly inflated
  • Brakes, are they working well, are they stopping you in a straight line.
  • Your ability as a driver. Are you ill, tired, on medication, have drunk alcohol, are distracted? All of these factors can affect your reactions when applying brakes.

Remember that being distracted while driving will reduce your concentration on the road.

Using a mobile phone is illegal while driving for a good reason, but you should avoid playing around with the radio, the heating or air-conditioning, and sat-navs.

Then, of course, there’s the distraction from other passengers, whether that’s your friends or family!

What is the separation distance?

The separation distance is simply a safety margin or empty road between you and the vehicle in front.

Separation distances are essential to allow you time to see and react appropriately to any potential or developing hazard.

Tips to ensure you don’t get caught out in the Theory Test

Make sure you read every question thoroughly. One very common occurrence is that test candidates do not read the question properly and as a result, mark the incorrect answer when being asked about stopping or braking distances.

If you’d like some practice right now, why not try our FREE Stopping Distance 3D simulator to help you learn, remember and visualise one of the toughest topics for learners!

Stopping distances

Always make sure that you read every driving Theory Test question at least twice on the day of your test, but most importantly TAKE YOUR TIME!

You’ll not score additional points for finishing your test early, so make good use of the allocated time you have to read every question and possible answer thoroughly.

Is the Stopping Distance 3D Simulator helping you to understand this often confusing topic?

Why not get our award-winning Driving Theory Test 4 in 1 App that’ll make sure you cover everything else that’s included in the 2020 Theory Test for learner drivers?

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