Commuters in Central Florida remember well the massive pileup on I-4 back on January 9, 2008. Because of dense fog and motorists driving too fast, 70 cars and trucks crashed into each other; five people died and 38 others were injured.

At this time of year many regions of the U.S. experience dangerous fog in early morning hours which can engulf roadways rapidly, making driving extremely hazardous. What can appear to be good visibility in one stretch of road can, with one turn, quickly become thick with fog and suddenly drivers realize their speed is too great for their now severely limited visibility.

Fog is basically a cloud at ground level. It forms when the temperature drops to the dew point (the temperature at which air is saturated), and invisible water vapor in the air condenses to form suspended water droplets. It can reduce visibility to 1/4 mile or less.

The Wisconsin Dept. of Transportation offers the following tips:

Drive with your lights on low beam. High beams will only be reflected back off the fog and actually impair visibility even more.

Reduce your speed -- and watch your speedometer. Fog creates a visual illusion of slow motion when you may actually be speeding.

Listen for traffic you cannot see. Open your window a little, to hear better.

Use wipers and defrosters as necessary for maximum visibility.

Use the right edge of the road or painted road markings as a guide.

Be patient. Do not pass lines of traffic.

Do not stop on a freeway or heavily traveled road. If your car stalls or becomes disabled, turn your vehicle's lights off, and take your foot off of the brake pedal. People tend to follow tail lights when driving in fog. Move away from the vehicle to avoid injury.

Remember, in fog you need to be extremely attentive. More space between vehicles give you more braking space and time to avoid a possible collision.