What are the requirements for headlights when driving in fog?

When driving in fog, using low-beam headlights is the proper choice. Low-beam headlights are designed to provide better visibility in conditions that are common with fog, such as reduced visibility and low light. High-beam headlights can create a glare that reflects off the fog droplets, making it more difficult to see.

In contrast to high beams, low beams aim downward, illuminating the road immediately in front of the vehicle and minimizing the amount of light that is reflected back by the fog, rain, or snow. This is crucial for maintaining visibility and safety while driving in these challenging weather conditions.

Fog lights, while useful, are typically used in conjunction with low beams rather than as a sole option. They are designed to light up the ground directly in front of the vehicle and are most effective when it is very foggy or during rain or snow, yet they do not replace the need for low-beam headlights. Not using any headlights at all is also unsafe and illegal, as it drastically reduces a driver's visibility as well as their visibility to others on the road.