What is the purpose of the “three-second rule” in driving?

The three-second rule is specifically designed to help drivers maintain a safe following distance from the vehicle in front of them. By counting three seconds from the moment the car ahead passes a fixed point (like a sign or tree) until you reach that same point, you can gauge whether you are maintaining a proper distance. This distance is crucial because it gives you enough time to react if the vehicle in front of you suddenly stops or slows down. Maintaining this following distance can drastically reduce the risk of collisions, especially in varying driving conditions such as rain or traffic congestion where stopping distances may be longer.

The other options do not pertain to the purpose of the three-second rule, as they focus on different aspects of driving, like determining speed limits, merging into traffic, or assessing signs, all of which are important but distinct from the concept of following distance.