How much distance should you leave?

The following distance is the safe distance you keep between your car and the vehicle in front, so that you have enough time to react if it suddenly brakes.

In dry weather, you can roughly estimate this distance by dividing your speed by two. For example, if you are driving at 50 km/h, you should keep a distance of about 25 metres. The faster you drive, the greater this distance should be.

You can easily check it using the two-second rule: choose a fixed point, such as a lamppost. As soon as the vehicle in front passes that point, start counting. If you reach it in less than two seconds, you are driving too close.

The reaction distance is the distance you travel between the moment you notice a hazard and the moment you start braking.

The time needed for this is called the reaction time. For an alert person, this is about one second on average.

In one second, you travel approximately:

• 14 metres at 50 km/h
• 20 metres at 70 km/h
• 34 metres at 120 km/h

So you cover this distance before you actually start braking. The higher your speed, the longer your reaction distance will be.

The braking distance is the distance you travel from the moment you start braking until you come to a complete stop.

The higher your speed, the longer the braking distance. It also depends on several factors:

• the road surface: on a dry road, the braking distance is much shorter than on a wet or snow-covered road
• the condition of your brakes and tyres
• whether your car is equipped with ABS

Add the reaction distance to the braking distance, and you get the stopping distance. This is the distance you travel from the moment you notice a hazard until you come to a complete stop.

The stopping distance is difficult to calculate exactly, but at the most common speeds it is approximately: