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But it will cost you absolutely nothing extra.

What’s your total braking distance at X km/h? If you don’t know the answer to that question, this blog post is for you.

It’s highly likely that you’ll have to answer a question like that on your theory exam – and even if you don’t, it’s still good to know.

And your braking distance is just a piece of the puzzle – there’s the reaction and stopping distance too.

There are two ways you can learn these distances:

 

1: You can memorise the distance for every single conceivable speed limit – but that would be more time-consuming (not to mention exhausting)

2: You learn a few simple calculations formulas to determine:

  • Your reaction distance
  • Your braking distance
  • Your stopping distance

In this blog post, you’ll learn:

  • Definitions for reaction, braking, and stopping distance 
  • How to calculate your reaction, braking and stopping distance – through a few easy formulas

IMPORTANT:

These formulas are for when road conditions are good – i.e. no water, ice, snow, or anything else that might cause loss of traction. 

Also, these measurements are for the metric system – i.e. we’re working with kilometers and meters here.

What is “reaction distance?”

reaction distance formula

Picture this – you’re out riding in a residential area. At one point, you see a car reversing out of a driveway, which blocks your path of travel.

You can’t go around it and the car driver can’t see you. You have no other choice but to stop.

The reaction distance is the distance from where you detect the car reversing out of the driveway to the point where you begin applying the brakes.

Reaction distance formula

Your reaction distance is calculated by:

  1. Removing the last digit for the speed you’re travelling at
  2. Multiplying it by 3

So for example, let’s say you’re travelling at 70 km/h.

In that case, your total reaction distance is 21 m, since:

7 (removing the “0” in “70”) X 3 = 21

Braking distance definition

braking distance formulas

Your braking distance is how far you travel between the point when you begin applying the brakes to the point when you’ve come to a complete stop.

It’s important to remember that you can’t stop a motorcycle immediately.

How to calculate your braking distance

The braking distance is a little more difficult to calculate accurately since it’s dependent on a couple of factors:

  • The condition of your tires (e.g. tire pressure & tread depth)
  • The conditions of your brakes
  • The road and weather conditions 
  • Whether you’re using both the front and rear brakes, or just one of the brakes

To make it easy for you, the formula for calculating the brake distance applies for when you’re using both front and the rear brakes, when the road conditions, your tires and your brakes are of good condition.

Similar to when you calculate the reaction distance, you remove the final digit for the speed you’re traveling at. 

However, when calculating the braking distance, you should remove the last digit and multiply the remaining digit by itself.

For example:

40 km/h = 4×4=16.

But we’re still not done – you also need to multiply that result (“16” in this case) by 0.4.

So, if your travelling at a speed of 40 km/h, your braking distance will be 6.4m, since:

16×0.4 = 6.4

 

driving test success 4 in 1 image

Stopping distance definition

stopping distance

The stopping distance is the combined distance between your reaction and your braking distance.

Pretty easy.

Overall stopping distance formula

Take the sum from the reaction distance and the braking distances and add them together.

For example, if your reaction distance is 21 meters and your reaction distance is 6.4 meters, your total stopping distance is 22 meters, since:

21+6.4 = 27.4

And that’s how to calculate your reaction, braking, and stopping distance.

To recap, here’s a quick summary:

reaction braking and stopping distance formula

Now you’ll know exactly how to answer the question “What’s your total stopping distance at x km/h?” without batting an eyelid.