What is the Three-Second Rule used for?

• A. To measure reaction time.
• B. To maintain a safe following distance under normal conditions.
• C. To determine braking distance.
• D. To calculate speed.

Answer: (B)

The main idea is to keep a safe following distance that gives you time to react and stop if the vehicle ahead suddenly slows. The three-second rule provides a simple, practical way to gauge that gap under normal conditions. Pick a fixed object on the road ahead. When the vehicle in front passes it, start counting seconds. If you reach that object before you’ve finished a count of three, you’re too close and should increase your following distance. This rule isn’t about measuring reaction time or calculating braking distance exactly; it’s a simple benchmark to ensure you have enough time to react and brake smoothly. Remember to extend the gap in poor conditions (rain, snow, night, or slick roads) since stopping distances are longer.