Calculate braking distance: Formula helps drivers
Created: 08/16/2022, 16:25
By: Simon Mones
Ever since driving school, every driver should know how the braking distance of a car is calculated.
All you need is a formula.
There are things that every driver should know in order to be able to drive safely on the road.
Accordingly, these are discussed in the driving school and are part of the driver's license test.
One such topic is the braking distance, which everyone should be able to calculate themselves.
However, a distinction must still be made between the normal braking distance and that in the event of emergency braking.
If danger is imminent, the driver applies the brakes and comes to a standstill accordingly.
How quickly can be calculated in both cases with a simple equation.
The braking distance of a car can be easily calculated using a formula.
(Iconic image) © Panthermedia/Imago
Calculate braking distance: Formula helps drivers
To calculate the normal braking distance, only one quantity is important: the speed.
It is the factor responsible for how long it takes for the car to come to a standstill and also determines the braking distance accordingly.
First, the speed is divided by ten.
This value is then multiplied by itself.
The formula is therefore:
(speed ÷ 10) x (speed ÷ 10) = normal braking distance in meters
So if you drive at 100 km/h on a country road, the calculation would look like this: (100 ÷ 10) x (100 ÷ 10) = 100. The braking distance is therefore 100 meters.
Calculate braking distance: The formula for emergency braking hardly changes
The formula for calculating the braking distance for emergency braking is hardly any different.
Again, the speed is divided by ten and multiplied by itself.
After that, however, the result is divided by two again.
So the formula is:
also read
Huge range: BMW manages 1,650 kilometers with one tank of diesel
Tesla: Full Self-Driving does not recognize children
[(Speed ÷ 10) x (Speed ÷ 10)] ÷ 2 = Danger braking distance in metres
So at 100 km/h the calculation would look like this: [(100 ÷ 10) x (100 ÷ 10)] ÷ 2 =50.
The car comes to a standstill after only 50 meters.
Calculate braking distance: reaction time has its own formula
However, both formulas only indicate the pure braking distance, the time that the driver needs to react is not taken into account.
It takes an average of one second before your foot hits the brakes.
During this time, however, the vehicle covers further meters, the so-called reaction distance.
But there is also a formula for this that helps with the calculation.
As with braking distance, speed is divided by ten and then tripled.
So the formula is:
(velocity ÷ 10) x 3 = reaction distance in meters
At a speed of 100 km/h, the reaction distance would be calculated as follows: (100 ÷ 10) x 3 = 30. This means that the car has covered 30 meters by the time the driver has reacted and initiated the braking manoeuvre.
However, if the response time is two seconds, this value doubles.
At three seconds, it triples again.
Calculate braking distance: The stopping distance is calculated from the sum of both formulas
In order to map the entire braking process, the so-called stopping distance, you have to add the braking distance and the reaction time.
The formula is correspondingly simple:
Braking distance + reaction distance = stopping distance
At 100 km/h, the braking distance is just 100 meters and the reaction value is 30 meters.
According to the formula, the stopping distance is calculated from both factors, i.e. 100 + 30 =130.
This means that the car has to travel 130 meters before it actually comes to a standstill.
