What is the three second rule with defensive driving?

The three-second rule in defensive driving is a guideline that helps drivers maintain a safe following distance from the vehicle ahead. It suggests that a driver should stay at least three seconds behind the vehicle in front of them to allow enough time to react in case of sudden stops or emergencies. To apply this rule, a driver can pick a fixed point on the road and count the seconds it takes for their vehicle to reach that point after the car ahead passes it. This practice enhances safety and reduces the risk of collisions.