What is the most important thing to do when driving in fog?

When driving in fog, using low beam headlights is the most effective approach for improving visibility. Low beams are designed to provide a wider and shorter range of light that helps illuminate the road directly in front of the vehicle without causing excessive glare. In contrast, high beam headlights can reflect off the water droplets in the fog, creating a blinding effect that makes it even harder to see. This is why low beams are recommended, as they penetrate the fog more effectively and help the driver see the road conditions clearly while also ensuring that other drivers can see them.

Driving at high speeds in fog is unsafe because it reduces the driver's ability to react to sudden changes in visibility or obstacles that may be present in the road. Additionally, turning off headlights altogether is unwise, as it would leave the driver with no illumination, increasing the risk of accidents. Therefore, using low beam headlights is crucial for safe navigation in foggy conditions.