Originally Posted by CKwik

I'd have to disagree here. Try driving an older car that uses Sealed beam headlamps in the fog. You will quickly realize how poor these lamps are for fog as much light goes up. Fog lights have sharp cut-offs to prevent light from going upward as this upward light will hit the water droplets directly in front of you and make it harder to see the road. They have no provisions to actually aid other drivers to see you better. In fact, anything that does so would likely mean this light is directed towards another driver's eyes, which would reduce their visibilty. This could raise the potential for a head-on collision. Generally, if you are in fog, you speed should be adjusted as such. Any headlamp of any color will likely be easy to spot in fog if you are driving a safe speed for conditions. Fog lights use cutoffs and are generally mounted lower than headlamps to help minimize the amount of fog that is in the light between you and the road. This helps a driver to see more of the road better.