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Topic 4 · Section 53

Fog

💡 Low-Beam Lights

  • Always use low beams in foghigh beams reflect off the fog and reduce visibility.
  • If equipped, use fog lights (typically yellow and low-mounted) along with low beams.

🐢 Go Slow

  • Fog can change rapidly — one moment it’s clear, the next it’s dense.
  • Drive at a speed where you can stop within your visible distance.
  • Use the right edge line (fog line) as a guide rather than the center line to avoid drifting into oncoming traffic.

🚨 Hazards in Extremely Dense Fog

  • If the fog becomes too thick to drive safely, do not continue — pull off the road (parking lot, exit, or as far off the pavement as you can).
  • Once stopped:
    • Turn on your emergency flashers so others can see you.
    • Wait for conditions to improve before getting back on the road.
  • These conditions are rare but dangerous — better to wait it out than risk it.

🪟 Open a Window?

  • Crack a window in thick fog to listen for cross traffic at intersections or curves where visibility is minimal.

🧘 Patience

  • Some drivers may speed through fog — let them go.
  • If you approach someone driving slowly, they may be doing so for good reason — follow at a safe distance unless it’s clearly safe to pass.

Check you have it

179 practice questions cover defensive driving and safe driving practices, each explaining the reasoning behind its answer.

Practise this topic

Source: California Driver's Handbook (DL 600, rev. 6/2025). Edited by Fernando Aguilera. Aprobify is not affiliated with the California DMV.

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