This morning we saw a prime example of the variable, quickly-moving, and dangerous power of fog.  According to the National Weather Service, think of fog as a cloud at ground level.  Fog 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.
Fog can easily and unexpectedly reduce your visibility to 1/4 mile or less, creating hazardous driving conditions.  Of course it was the right mix of fog and low-level smoke from area brush fires which triggered the deadly Polk Pile-up along I-4 in January. 
If you can’t postpone your trip until dense fog lifts—usually by late morning or the afternoon – here are several important tips to respond to fog and low visibility conditions:
• Use your low beam lights when driving in fog. High beams reflect light off of the fog, actually decreasing your visibility. 
• Lower your speed.  Speed obviously reduces your opportunity to respond to rapidly changing conditions and road hazards and increases the likelihood of chain-reaction collisions. 
• Monitor your speedometer.  Fog creates a visual illusion of slow motion, causing you to unintentionally increase your speeds. If can’t see more than 40 feet ahead (only several car lengths), your speed needs to be reduced to less than 20mph.
• Use wipers and defrosters when needed. 
• Listen for traffic you cannot see.  Roll down your window a few inches to hear accidents ahead, emergency vehicles or stranded motorists.  .
• Use the clearest road markings, often to the right side of the road, to guide you when highways lines and lanes are blurred because of fog. 
• Be patient and do not pass other traffic when driving in fog.
• Pay special attention to roadways near or over water.  Bridges and low-lying are especially susceptible to fog. 
• Do not stop on a freeway or heavily traveled road. If your vehicles stalls or breaks-down, take your foot off of the brake pedal and turn your lights off.  Drivers tend to follow tail lights when driving in fog. Get out of your vehicle and move to a safe location to prevent injuries if your vehicle is rear-ended.