As a prologue, we must remind you that driving in fog is much more dangerous than any other weather condition, with the highest rate of fatal accidents per number of cars on the road. If you encounter thick fog, it's best to get fully off the road and wait for the conditions to improve. But if you must keep driving, following these precautions can greatly increase your chances of arriving safe:

Use your fog lamps. And if your car has rear fog lamps, make sure they're on—in addition to your regular headlights—as they greatly aid visibility to other traffic approaching from the rear. Fog-lamp use, in poor-visibility conditions, could mean the difference between an accident and not. Some cars have lights that look like fog lamps, but they're only cheap, non-functional imitations: Generally, real fog lamps have glass lenses and are hot to the touch, and they should carry an SAE-F rating (as opposed to driving lights, which carry an SAE-E rating and are for looks only). Also make sure they're aimed properly (mounted at most 30 inches from the ground with the top of the beam aimed four inches down over 25 feet). Special tinted lenses have not been shown to help in fog either, and they tend to distract other drivers. And never use your fog lamps in clear weather: They might improve your visibility a bit, but they'll blind other drivers.

Low beams are best. High beams will disperse in the fog, making visibility worse for you and other drivers. Also, if your headlights have a dipped setting (aimed downward), use it (though few American vehicles do). Make sure your full headlights—not just daytime running lamps—are on in fog even if it's during the day.

Keep your car clean. Ordinary road grime can reduce the brightness of headlights by up to twenty percent, and the same applies to front and rear fog lamps. Get in the habit of wiping off your lights at the gas station; that way you're ready for those low-visibility conditions.

Keep the view clear. When fog is obscuring your visibility already, the last thing you want is fogged windows. Periodically, if not constantly, use the defroster and windshield wipers. Moisture can build up on the windshield both inside and out; the air conditioning setting will help keep moisture from building up inside.

Minimize your distractions. Don't listen to music or talk on your cell phone. Turn down distracting noises so you can listen for vehicles you cannot see.

Use the side of the road as a guide. Use the right edge of the road or the painted white line along the right side of the lane as a guide for positioning the car in your lane. Approaching cars could blind you momentarily if you're looking at the centerline.

Brake and signal early. If you miss a turn, never brake quickly or back up to the intersection. Remember the car behind you can't see any better. If you need to pull off the road and can do so only partially, or if your car unexpectedly stalls out, make sure you have some easily accessible emergency flares in your car.

Check your rear-view mirrors. Look for approaching headlights. Gently touch the brakes as another car approaches from behind, to signal the other driver.

Be alert for slick roads. Remember that fog is a form of precipitation; it may leave the roads slick or icy, especially in cold weather or mountainous terrain. If there's fog AND ice, pull off the road at the next safe place—it's not worth going on.

Slow down. Most accidents in foggy conditions happen because the driver of one of the vehicles is going too fast for the conditions and can't slow down in time for another vehicle. If the fog lifts, proceed cautiously. Fog tends to be patchy, and you could be enveloped in it again.


©2008 by The Car Connection™ All Rights Reserved—The Car Connection is a Trademark of Car Advisory Network

Bengt Halvorson

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