How far should your reactionary gap be when pursuing a vehicle?

• A. 4 seconds.
• B. 2 seconds.
• C. 6 seconds.
• D. 1 second.

Answer: (A)

The main idea here is how much time you keep as a buffer behind the vehicle you’re pursuing. That buffer, called the reactionary gap, is a time-based distance I need to account for—my eyes, brain, and foot all taking a moment to react and brake. In pursuit driving, four seconds is the standard minimum because it gives a solid safety margin for sudden actions by the lead vehicle (like braking hard, turning, or stopping), plus enough space to react and brake without slamming into the other car.

To use it in practice, pick a fixed point on the road. When the lead vehicle passes that point, start a four-second count; you should reach the same point after about four seconds. Adjust for conditions: in wet or icy conditions or with reduced visibility, increase the gap; in clear, light traffic you might maintain roughly four seconds, but you should never drop below that minimum.

Shorter gaps greatly increase the risk of rear-end collisions if the lead car slows or stops suddenly. Larger gaps—like six seconds—can hinder pursuit effectiveness in normal conditions, though they might be appropriate in high-risk situations. The four-second reactionary gap is the standard balance between safety and maintaining effective pursuit.