Following distance is measured in time, not metres, and that is the whole point: the faster you travel, the more physical space those same seconds buy you.
| Vehicle | Recommended | Absolute minimum |
|---|---|---|
| Light motor vehicle (Code 8) | 3 seconds | 2 seconds |
| Heavy motor vehicle (Code 10 / 14) | 6 seconds | 3 seconds |
How to measure it
- 1Pick a fixed object ahead — a bridge, a sign, a line across the road.
- 2When the vehicle in front passes it, start counting seconds.
- 3If you reach the same object before your count is done, you are too close.
Counting in whole seconds is more reliable than judging car lengths, and it works identically at 60 km/h and at 120 km/h.
Why heavy vehicles need double
A loaded truck carries several times the mass of a car, and stopping distance scales with that mass. Six seconds is the recommendation for a heavy vehicle against three for a light one, with three as the bare minimum against two.
This is also why you should never cut in front of a truck and brake — you have just removed the gap its driver needs and cannot instantly recreate.
When to increase the gap
- Rain, or any wet or slippery surface.
- Loose surfaces such as gravel, where tyres grip far less.
- Poor visibility — mist, dust, smoke or darkness.
- When you are carrying a heavy load.
- When travelling fast.
- When the vehicle behind is following you too closely, so you have room to brake gently instead of hard.
Being tailgated is a reason to increase the gap in front of you, not close it. More space ahead means you can slow gradually rather than braking sharply into the vehicle behind.
How it is marked in the driving test
Following too closely is not a one-off penalty. If you fail to hold the minimum gap, penalty points are allocated every five to eight seconds for as long as it continues, which adds up quickly.
Frequently asked questions
Is it the 2-second or the 3-second rule?
Both. Three seconds is the recommended safe gap for a light vehicle; two seconds is the absolute minimum, not the target.
Does following distance change with speed?
The number of seconds stays the same. The distance those seconds represent grows with speed, which is exactly why time is used rather than metres.
What is the gap for a heavy vehicle?
Six seconds recommended, three seconds minimum.
Why measure in seconds instead of car lengths?
Car lengths are hard to judge accurately and mean different things at different speeds. Seconds work at any speed.