Practice question

When driving in fog, what lights should you use?

  1. Use your high beam headlights
  2. Use your low beam headlights
  3. Use your fog lights only
  4. Keep your headlights off

Answer: B — Use your low beam headlights

When driving in fog, using your low beam headlights is the correct approach because low beams are designed to provide adequate illumination without reflecting too much light back into your eyes, which can happen with high beams. In foggy conditions, the moisture in the air can reflect the light from high beams, making visibility worse instead of better. Low beam headlights cast light closer to the ground, which helps drivers see the road ahead more clearly without causing glare. While fog lights can also be beneficial in thick fog, low beams are essential as a primary lighting source to maintain visibility and allow other road users to see your vehicle. Keeping headlights off reduces visibility significantly and is not a safe option when driving in such conditions.

Practice more: Idaho Written Driver's License Practice Test →