It is raining. You choose a sign post ahead. The rear of the car in front passes the post, and you reach the post as you count "one thousand two." What should you do?

Correct answer: Drop back until you count at least four seconds before you reach the post.

Why

The count check measures time, not distance, so it works at any speed. Pick a fixed object, start to count when the rear of the vehicle ahead passes it, and stop counting when your front reaches it. Wet roads lengthen your stopping distance, so the manual calls for at least four seconds in bad weather. It also tells you to add space at night, in fog, and behind large vehicles or motorcycles.

Verified against Oklahoma Driver Manual · Following distance · p. 34, 42, 44