<P> The two - second rule (also known as the three - second rule in some states) is a rule of thumb by which a driver may maintain a safe trailing distance at any speed . The rule is that a driver should ideally stay at least two seconds behind any vehicle that is directly in front of his or her vehicle . It is intended for automobiles, although its general principle applies to other types of vehicles . </P> <P> The two seconds is not a guide to safe stopping distance . It is more a guide to reaction times . </P>

The minimum safe following distance in traffic is