Braking distance and stopping distance

Stopping distance = thinking distance + braking distance

During your reaction time you are still travelling at full speed. Only then do the brakes start to work. An alert driver needs about one second to react. If you are tired or distracted, it takes longer.

Working out thinking distance

Divide your speed in km per hour by 3.6. That gives the metres you travel each second. With a reaction time of one second, that is also your thinking distance.

30 km per hour	about 8 metres
50 km per hour	about 14 metres
80 km per hour	about 22 metres
100 km per hour	about 28 metres
130 km per hour	about 36 metres

Braking distance grows much faster

Braking distance grows with the square of your speed. Drive twice as fast and your braking distance is roughly four times as long. On a wet or slippery road, or with a heavily loaded car, it is longer still.

What the law says

You must always be able to stop within the distance you can see to be clear (article 19 of the RVV 1990). In fog, in the dark or before a bend that means driving slower, even when the speed limit is higher.

Try it yourself

Three questions from RijGo, with an explanation after every answer.