When is the use of fog lights and low-beam headlights permitted during daylight?

The use of fog lights and low-beam headlights during daylight is permitted in conditions where visibility is significantly reduced, such as fog or heavy rain. Fog lights are specifically designed to illuminate the road directly in front of a vehicle in low-visibility conditions without causing glare that affects other drivers. Low-beam headlights are also appropriate for maintaining visibility in adverse weather conditions, as they provide adequate lighting without blinding oncoming traffic.

Both fog and rain can create hazardous driving situations where the normal visibility is compromised. Thus, using these types of lights helps enhance safety on the road by making the vehicle more visible to others and improving the driver's ability to see the road and obstacles. This is why the correct answer encompasses both scenarios, as each warrants the use of additional lighting to ensure safety while driving during the day when visibility is impaired.