When driving in fog, you should:

1. Slow down and use your low beam headlights. ✓
2. Slow down and use your high beam headlights.
3. Turn your lights on and off to warn other drivers.

Answer: A. Slow down and use your low beam headlights.

When driving in fog, slow down and use your low-beam headlights.

Why this is the answer

The handbook's fog guidance says to drive slowly and to use low beams, because high beams bounce back off the fog and create glare. It also says to turn on low beams whenever you need your wipers because of fog, rain, or snow, and to never drive with only parking or fog lights. Slowing down pairs with the handbook's advice to keep your stopping distance inside the space you can actually see ahead.

Why the other answers are wrong

• B. Slow down and use your high beam headlights. — High beams are the wrong setting in fog because the light reflects back off the fog and causes glare, which makes it harder to see.
• C. Turn your lights on and off to warn other drivers. — Flipping your lights on and off is not what the handbook advises for fog; it says to use low beams steadily and, if the fog gets too thick, to pull off and turn on your emergency flashers.

Remember it

Think of fog as a mirror: low beams point down and under it, high beams bounce straight back at you.