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Fog Safety

By Heather Klinefelter, Outreach Specialist

Fog is in the air tonight.  And early in the morning.  And on rainy days.  You get the idea.  Fog is a regular occurrence during fall and spring.  It is actually one of the most dangerous driving conditions you can encounter.  They don’t call it pea soup for nothing – it’s hard to see through!

Whether it’s dropping your kids off at school, your morning commute, your evening dinner date, or driving home from that midnight mandatory overtime, fog is a constant companion in the fall and spring.  Fog occurs when a cloud touches the ground.  This can happen for many reasons.

According to National Geographic: Fog shows up when water vapor, or water in its gaseous form, condenses. During condensation, molecules of water vapor combine to make tiny liquid water droplets that hang in the air. You can see fog because of these tiny water droplets. Water vapor, a gas, is invisible.  Fog happens when it’s very, very humid. There has to be a lot of water vapor in the air for fog to form.

So how do you stay safe during this weather phenomenon?  To prevent commute disruption, PennDOT offers the following safety tips for driving in fog:

  • Be cautious. Slow down and increase your following distance to ensure enough reaction time and stopping distance between vehicles;
  • Allow additional time to get to your destination;
  • Check your vehicle’s headlights, taillights and turn signals to ensure they are working properly;
  • Along with low beam headlights, use windshield wipers and defrosters to maximize visibility;
  • Use roadside reflectors or the right edge of the road as a guide. If you cannot see, pull completely off the road in a safe location;
  • Be patient and avoid passing other vehicles or changing lanes; and
  • Watch for pedestrians or slow moving vehicles along your commute route.


The National Weather Service concurs – it might be tempting to use your high beams, but in practice it really just leads to more problems.  “In extremely dense fog where visibility is near zero, the best course of action is to first turn on your hazard lights, then simply pull into a safe location such as a parking lot of a local business and stop.”

Remember, in PA if it’s misting, raining, or foggy, you must have your wipers and lights on.  It’s the law.  Go slowly and turn on your defrosters.  Because of the temperature disparities that cause fog, you can also experience fog inside your car.  You want to be able to see on your commute for your safety and the safety of other drivers.  Getting that defroster just right, even if you need to crack a window, will help improve visibility to keep you and other drivers safe.

While it may be tempting to slow down to a crawl during heavy fog, it’s not always the safest thing.  “When you come to an especially dense area of fog, your first instinct might be to stop so that you can regain your bearings. Remember that other vehicles are behind you and will be coming upon the same reduced visibility. Stopping in the middle of the road in decreased visibility will increase your chances of getting rear-ended by an approaching vehicle. Stopping your car could cause a chain reaction and a major pileup.” – Driving Tests

And of course, don’t forget the deer!  Fall is rutting (mating) season for deer, and they are out in droves trying to find a mate.  This means increased chances of hitting one during your commute.  “Overall, drivers in the United States have a 1 in 116 chance of striking a deer or another animal, according to the study. In Pennsylvania, that number drops to 1 in 51, making the Keystone State No. 3 overall.  That makes Pennsylvania a high-risk state for deer strikes.” – Patch  I’m sure we all know someone who has hit a deer or narrowly avoided one.  Be alert.

As always, stay safe on your commute and don’t forget to record your green trips in Commute PA.  Visit our website for more information, and IKYMI our last blog on fall driving safety.