SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/drive-count-following-gap

How do you measure a three-second following gap?

Count from when the lead car passes a fixed point.

  1. Count between the same fixed point ✔
  2. Count car lengths in your mirror
  3. Count lane lines beside you

Why: Pick a sign, shadow, or other fixed point. Start counting when the vehicle ahead passes it, and make sure at least three seconds pass before you reach it.

Huh, didn't know that: If you reach the point too soon, ease off the accelerator and rebuild the gap.

The dad joke
The roadside sign became a counting coach without saying a word.
Like this card?
Play the game

References

Answer: Count between the same fixed point. Pick a sign, shadow, or other fixed point. Start counting when the vehicle ahead passes it, and make sure at least three seconds pass before you reach it.

  1. California Driver's Handbook, Glossary www.dmv.ca.gov/portal/handbook/california-driver-handbook/glossary
    When the vehicle in front of you passes a certain point, such as a sign, count three seconds.
    Checked 2026-10-09.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Cars & DrivingIn good conditions, what minimum following gap do many state manuals recommend?Cars & DrivingWhat is safer than weaving through traffic?Cars & DrivingLap and shoulder belts cut a front-seat car rider's risk of being killed in a crash by about how much?

That's stuff everyone should know.