What is the "2-second rule" used for?

The "2-second rule" is a guideline that helps drivers maintain a safe following distance from the vehicle in front of them. This rule states that when following another vehicle, a driver should ideally stay at least two seconds behind it. This time gap allows drivers adequate time to react to sudden stops or emergencies, reducing the risk of rear-end collisions.

To use the 2-second rule, a driver simply picks a stationary point along the road, such as a sign or a tree. When the vehicle in front passes that point, the driver should count "one thousand and one, one thousand and two." If the driver reaches the same point before finishing the count, they are too close and should increase their following distance. This technique not only enhances safety but also provides a buffer against variable driving conditions, such as wet or icy roads where stopping distances may increase.

In contrast, the other options do not relate to the primary purpose of the 2-second rule. Calculating travel time is more about distance and speed, while measuring speed directly involves instruments like a speedometer. Estimating fuel efficiency focuses on how far a vehicle can travel on a certain amount of fuel, which is unrelated to following distances between vehicles.