An Excerpt from the course on Transport Operations

Fog, mist, dust storms, and smog cause poor visibility.  Do the following:

1. Slow down but avoid decelerating suddenly.
2. Watch the road ahead and behind carefully for other cars that are traveling slowly.
3. Turn on your lights (never high beams), regardless of the time of day, and use your wipers.
4. If you travel 15 miles per hour or more below the speed limit, use four-way flashers. Use the four-way flashers if you pull off the road and stop.
5. Use the defroster to keep as much fog as possible off the inside of the windshield.
6. If you must stop, tap the brake pedal several times so that your brake lights warn other motorists behind you. And lastly,
7. Fog can occur suddenly, and patches of greater density may appear. Be aware of the vehicles in front of you.