Headlights should be activated when visibility is?

Headlights should be activated when visibility is low, such as during rain, fog, snow, or at dusk and dawn. This ensures that drivers can see the road and obstacles clearly while also making their vehicle more visible to others. Additionally, it's important to use headlights in poorly lit areas and when driving through tunnels or shaded regions. Always follow local laws regarding headlight use to enhance safety on the road.