It is recommended that you use low beams while driving in fog. The low beams are aimed slightly downward, and thus the light reflects downward off the water droplets in the fog and onto the ground ahead. Still, a small amount does reflect back to the driver's eyes, but not nearly so much as if the high beams are used.
IF your vehicle is equipped with "Fog Lights" then use them in addition to the low beams. The amber/or yellowish color of the fog lights does not reflect back as badly as white or blue light, and thus reduces glare and appears to provide better "penetration" of the fog.
No, you should not use high-beam headlights at all in heavy fog.
Yes, when driving in foggy conditions you should use your headlights which allows oncoming drivers to see you at the earliest possible moment. However, for safety, you should not use your highbeams [bright] as the fog will reflect back much of the light, reducing your ability to see into [through] the fog.
No. Either use your regular headlights since they help other drivers see you. Also, slow down.
Full beam lights in foggy conditions will reflect the light directly back at the driver. Dipped headlights should be used instead.
Not use their high beams and drive dramatically lower speeds.
overdrive
You don't want to use high beams in foggy weather or snow. It actually makes it more difficult for you to see as the light reflects off the snow or fog.
You should not use your high beams in the fog. Your high beams will reflect off of the water in the air from the fog making it even harder to see.
Fix My Headlights is a great place to go to correct foggy headlights. They are very trusted and can do a very good job. I do not know anyone who has used it but it seems good.
low beam
When its foggy or a snowstorm
Your headlights should be on whenever it will make a difference on the road. If you can look at the road and be able to tell that your headlights are on/off, then they should be on. Some states, such as New York, require headlights to be on when visibility is limited, such as in rain or fog, even in the day, regardless of whether or not you can see them on the road. In fact, one of the criteria for headlights is whether or not you are using your windshield wipers. At dusk or, in some states where mandated, when it is raining or foggy and you need to turn on your windshield wipers.