Driver's License Test Prep
California Practice Defensive Driving

You are driving in heavy fog. Which headlights should you use?

  1. A.
    High-beam headlights
  2. B.
    Fog lights on their own
  3. C.
    Low-beam headlights Correct
The Why

The answer is "Low-beam headlights"

In heavy fog the California manual tells you to use low-beam headlights, because high beams reflect back off the fog and cause glare that makes it harder to see. Some drivers reach for high beams thinking more light equals better visibility, but the reflection off the fog undoes any extra brightness.

Why the others miss

The traps in the wrong answers

A. High-beam headlights

The manual says high beams reflect back off the fog and cause glare, so they make visibility worse. This answer applies the general night-driving reflex that more light equals more visibility, missing the fog exception the manual spells out.

B. Fog lights on their own

The manual forbids driving using only parking or fog lights. This answer treats fog lights as sufficient by themselves, when the manual bars that setup and still requires headlights.

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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