Be honest: During your last emergency stop, your pulse was racing and you came to a stop just in time. You’re lucky. But braking better not be a matter of luck.

You should be able to calculate the stopping distance

Important requirement: You can estimate the distance you need to go from a certain speed to a standstill. What I’m talking about is known in the trade as “stopping distance”. You should be able to calculate this as well as the so-called “braking distance” and “reaction distance”. So that your guardian angel doesn’t have to constantly work extra shifts.

According to the Federal Statistical Office, there are about 2.4 million traffic accidents on Germany’s roads. A frequent cause: underestimating one’s own reaction time and the actual braking distance until the final stop. Once learned in driving school, the calculation of braking, reaction, and stopping distances in everyday traffic suddenly degenerates into a great unknown. But as I will show you in a moment, it is not that difficult.

Stopping distance = reaction distance + braking distance

The stopping distance consists of the reaction distance and the braking distance. The decisive variable for calculating all three distances is literally always in the hands of the motorcyclist: speed.

1. the reaction distance: seeing, recognizing, and reacting takes time

The reaction time is the time it takes the driver to notice a threat and then apply the brake. If there are no medications, alcohol or other drugs involved, this usually takes a second. The metres that the driver covers at a certain speed during this time is the reaction distance. It is calculated by the following rule of thumb: Reaction distance = (speed ÷ 10) × 3. At a speed of 100 km/h the reaction distance alone is 30 metres.

Examples for the calculation of the reaction distance:

Speed in km/h

Reaction distance in metres

Note:

If the reaction time is doubled, the reaction distance is also doubled!

2. the braking distance: estimate when your vehicle will stop after the start of braking

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Formula for calculating the braking distance.

The braking distance is the distance travelled from the start of braking to the standstill of the vehicle. In other words: how many metres your motorcycle will travel while braking. Without reaction time or reaction distance (see above). The following formula has proven to be useful for calculating the braking distance: (Speed ÷ 10) × (Speed ÷ 10). At a speed of 100 km/h the braking distance is therefore a full 100 metres..

In the case of emergency braking, in which the brake and clutch are pressed simultaneously, the braking distance is reduced by half again each time. The formula must therefore be added: (speed ÷ 10) × (speed ÷ 10) ÷ 2. At our previous starting speed of 100 km/h, it takes 50 metres to stop your machine with an emergency stop.

Further examples for the calculation of the braking distance:

Speed in km/h

Braking distance “normal”

Braking distance “emergency”

As simple as the calculation sounds:

Whether during normal or emergency braking – in both cases the braking distance quadruples at double speed. According to our rule of thumb, the stopping distance is only 9 metres at 30 km/h, but it increases to 36 metres at 60 km/h. Tragic, as every metre is vital when braking!

3. the stopping distance: the actual distance to get to a halt is decisive

The stopping distance is once again considerably longer than the braking distance. It begins when the danger is detected and ends when the vehicle comes to a halt. The stopping distance is therefore made up of points 1 and 2 – the reaction distance and the braking distance. I must therefore determine and add two partial values (reaction distance + braking distance) in order to calculate the required stopping distance.

Expressed in the formula: (speed ÷ 10) × (speed ÷ 10) + (speed ÷ 10 × 3). For my standard example at 100 km/h, the stopping distance under normal braking is 130 metres.

Further examples for the calculation of the stopping distance:

Speed in km/h

Stopping distance “normal”

stopping distance “emergency”

Important:

All the calculation models I have mentioned are based solely on rules of thumb. They assume ideal conditions like e.g. dry roads, optimal braking effect, and good tyres. If the general circumstances worsen or if technical or human deficits impair the situation, the stopping distance will also be extended.

Decisive criteria for the length of the braking distance in addition to the speed:

  • weather conditions
  • Soil or road conditions
  • Technical standard of the vehicle (e.g. ABS available)
  • Condition of the brakes
  • Brake actuation force
  • tyre tread depth
  • Condition of the driver (e.g. reaction time due to fatigue possibly higher than 1 second)

What else you should think about

Although motorcycles are lightweight compared to cars, their braking distance is usually slightly longer. This is partly due to the somewhat weaker brakes. On the other hand only two tyres have road traction. So the friction is lower and the braking effect is correspondingly weaker.

My advice

Just learn the required stopping distance for certain speed levels by heart using the formula and my examples. So you can make yourself aware of it in every situation. Apart from that: Drive with foresight and according to the conditions. If, for example, in fog the visibility is less than 50 metres and you notice obstacles and brake, you will not be able to stop in time at a speed of 60 km/h. And with the emergency braking that might save you, you risk your own fall or a rear-end collision in the rain.

More tips

You would also like some tips for driving curves? We have them for you too!

Author of the article

Thorsten Rechtien

Thorsten Rechtien

Competence Center

He is the man who knows the answer to (almost) everything. Not only during working hours, but also after work, his heart beats for vehicles – especially those with 2 wheels. But he also likes to swap the wheels for his sailing boat.

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Comments

2 Comments

  1. Roya

    Very nicely explained!
    Espetially with a fluent English from inside Germany and up to date infos!
    Very good. Thanks!

    Reply
  2. Jack Huang

    1) Braking distance depends on braking forces applied. If you ignore the braking force in your calculation, you are not doing a braking calculation.
    2) People have used vehicle braking for 1,000 years, but it looks like they don’t know how to calculate braking distances correctly theoretically. To do it right, the key word is “friction”.
    3) Reaction distance is unnecessary in braking calculation.

    Reply

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