I see the kind of fog you're probably talking about very frequently. I'm in the mountains and the hours before dawn often start with low level clouds laying down on the road and they are crazy thick. For fog/snow that thick, the best i've used are colored lenses since they bounce back less. They need to be mounted as close to the ground as possible, and the reflector should be a proper fog lens/reflector that creates the wide flat bar of light, not just a diffused wide angle, circular beam. The best fog lens setups make a wide bar beam pattern with diffused light below it and almost no light above the bar. .