It's very important to make sure you have a safe distance between you and the vehicle in front, so you will have enough time if you need to stop suddenly.
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 - putting your foot on the brake - as well as time for the brakes to slow the vehicle down.
The faster you are going, the longer it will take to stop. This means you must increase your following distance as you increase your speed.
When driving a heavy vehicle, following distances should be increased from two seconds (for a car) to four seconds, depending on how laden your vehicle is. If fully laden, it will take much longer to stop.
You will need to increase your following distance when fully loaded, in bad weather and when going downhill. A heavy combination vehicle should have a six-second gap.
A heavy rigid vehicle should have a four-second gap. To check you are travelling four seconds behind the vehicle in front:
If you pass the landmark before you finish saying those 16 words, you are following too closely – slow down, pick another landmark and repeat the words to make sure you have increased your following distance.
The purpose of the two and four second rules is to provide a safe following distance between vehicles travelling at the same speed.
Reaction times can be longer for some people, or when you are tired, so take this into account and increase your following distance.
Last updated: 16 July 2014