Headlights must be used when a regulatory white road sign states that headlights must be on:

• A. True
• B. False
• C. Only at night if visibility is poor
• D. Only when driving in fog

Answer: (A)

When a regulatory white sign tells you that headlights must be on, you must turn them on. This kind of sign creates a mandatory rule for that area or situation, so compliance is required regardless of whether it’s day or night, or what the weather is like. It’s about safety and visibility for everyone on the road in that zone.

The other ideas would ignore the explicit instruction of the sign—headlights aren’t optional or limited to nighttime or poor visibility in this case. Activate your headlights when you see the sign and keep them on as long as you’re under its guidance.