When must you use headlights during the day?

Answer: B — When visibility is poor, such as in fog or heavy rain

The requirement to use headlights during the day primarily focuses on safety and visibility concerns. Option B highlights the importance of using headlights when visibility is poor, such as during fog or heavy rain. In these conditions, it may be difficult for other motorists to see your vehicle, which can lead to dangerous situations. By using headlights, you increase your vehicle's visibility to others, thereby improving overall safety on the road. In many jurisdictions, including areas covered by US Forces in Germany, drivers are encouraged to keep their headlights on during low-visibility conditions to enhance their own visibility and the awareness of others about their presence. This practice helps prevent accidents and ensures that vehicles are more easily seen in challenging weather conditions.