The 3-second rule is a rule of thumb for estimating how much distance you should keep between you and the car in front, as a minimum. When road conditions require it, or when driving at speeds above 80 km/h, you will need to keep a greater distance.

As this distance is largely decided by the braking distance, it is not affected by whether or not your car is equipped with ABS brakes.

A fixed distance of 45 metres to the car in front will in some instances be too long and in some instances too short, depending on speed and road conditions.