Driver's License Test Prep
California Practice Defensive Driving

Fog becomes too thick to drive safely. What should you do?

  1. A.
    Continue slowly with your parking lights on
  2. B.
    Pull off the road, turn on emergency flashers, and wait Correct
  3. C.
    Follow closely behind a truck ahead of you
The Why

The answer is "Pull off the road, turn on emergency flashers, and wait"

The manual says that when fog becomes too thick to drive safely, you should pull off the road, activate your emergency flashers, and wait for conditions to improve. Choice C tempts drivers who reach for the folk trick of following a truck's taillights through fog, a habit the manual specifically warns against by telling you to add following distance, not shrink it.

Why the others miss

The traps in the wrong answers

A. Continue slowly with your parking lights on

The manual forbids driving using only parking or fog lights. This answer keeps moving with what looks like a minimal-glare setup, a folk habit the manual overrides by banning parking-lights-only driving.

C. Follow closely behind a truck ahead of you

The manual treats close following in fog as unsafe; its instruction is to increase following distance or pull off. This answer reaches for the folk trick of trailing a truck's taillights, a habit the manual specifically flags as unsafe in these conditions.

The Rule

This question tests your knowledge of Defensive Driving in California. Source: California Driver Manual, "Fog or Heavy Smoke," p.64..

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