It’s very important to make sure you have a safe distance between you and the vehicle in front, so you have enough time if you need to stop suddenly. It also gives you a better view of the road ahead and the hazards you need to avoid. 

Several seconds will pass from the time you see the hazard until you can come to a complete stop. This is because you need time to react to the hazard and take action. Consider the time it takes to put your foot on the brake, as well as the time for the brakes to slow the vehicle down. 

The faster you’re going, the longer it’ll take to stop. This means you must increase your following distance as you increase your speed.


Some people take longer to react to hazards than others.

If you’re tired, or your reaction times are slower than normal, you should increase your following distance.

Keeping a safe following distance

A good way to make sure you always keep a safe following distance is to use the 2-second rule or the 4-second rule.

The 2-second rule

Under normal conditions, the 2-second rule is an easy way to make sure you’ve allowed enough following distance between your vehicle and the vehicle in front, no matter what speed you’re travelling at. 

To check if you’re travelling 2 seconds behind the vehicle in front:

  • watch the vehicle in front of you pass a landmark – such as a sign, tree or power pole – at the side of the road
  • as it passes the landmark, start counting ‘one thousand and one, one thousand and 2’
  • if you pass the landmark before you finish saying those 8 words, you're following too closely – slow down, pick another landmark and repeat the words to make sure you've increased your following distance.
A blue car is travelling behind a red car. A black arrow is stretched between the 2 cars with the text 2-second rule along it. The side of the road shows markers. 0 seconds is written above the 1st marker and 2 seconds is written above the 2nd marker.

The 2-second rule

The 4-second rule

In bad weather, when the road is wet or slippery, or if you’re towing a trailer, you need to increase your following distance to 4 seconds, because you’ll take longer to stop if you need to.

If the vehicle behind you is following too closely you should:

  • increase your following distance to 4 seconds from the vehicle in front of you. This gives you time and space to slow down gradually and reduce the risk of sudden braking and being hit from behind.
  • when it’s safe, you can pull over to the side of the road and let the vehicle pass you.

To check that you’re travelling 4 seconds behind the vehicle in front, follow the instructions for the 2‑second rule, but count from one thousand and one to one thousand and 4 instead.


When you’re following another vehicle and you don’t intend to overtake them, you must leave enough space in front of your vehicle for vehicles behind you to pass.