Dense fog has been draped over parts of California over the past week, seriously compromising visibility for drivers in the state. As a result, the Automobile Club of Southern California issued a list of safety tips aimed at helping drivers avoid crashes arising from poor visibility.

But foggy conditions are of course a national concern. Last month, heavy fog led to a Thanksgiving Day traffic pileup on Interstate 10, west of Beaumont, Texas. Two people were killed and 29 others suffered injuries. About a dozen had to be hospitalized. An estimated 95 vehicles were damaged. The Texas Department of Public Safety, which is investigating the tragedy, said there were 18 separate collisions on the highway – 14 of which were on the eastbound lanes. The chain-reaction crashes left cars and trucks twisted and on top of one another. 

So now is a good time to remind your fleet drivers to take extra precautions whenever fog is in the weather forecast.

"Motorists should plan extra time and monitor their speedometer while making their commute or trip because speeding or even driving at or near the speed limit in foggy conditions is unsafe," said Anita Lorz Villagrana, manager of the Auto Club’s community programs and traffic safety. “It’s a lot more difficult to see vehicles and also to judge the speed of vehicles you can see. Fog creates an illusion of slower motion when drivers may be speeding in reduced visibility conditions.”

Here are some tips from the Auto Club of Southern California:

• Park in a closed garage. This reduces condensation and moisture on vehicle windows when you start out for your trip.  

• Defrost first. Before turning on the defroster, allow the engine to warm up. Turn the heat control on and if the vehicle’s windshield begins to get cloudy, open the side window slightly and turn the defroster to a higher speed. If you have an air conditioner, use it briefly to help clear the windows. 

• Drive with lights on low beam. High beams will reflect off the fog, creating a “white wall” effect. If your car has fog lights, now is the time to use them. 

• Reduce speed. Fog creates visual conditions that fool the driver into driving faster or slower, so slow down to a reasonable and legal speed and use your speedometer to gauge it. Multi-vehicle collisions occur because drivers are going too fast. 

• Partially open the driver’s side window. Listen for traffic you can’t see and anticipate problems.

• Keep a safe distance. In foggy weather, increase the braking distance between you and the vehicle in front of you. 

• Drive cautiously. Avoid passing other vehicles and changing lanes, if possible. 

• Stay informed. Tune into radio weather reports to know where traffic congestion or crashes might be located. If possible, avoid these areas. If stalled or a crash occurs, attempt to exit the freeway or pull well onto the shoulder and turn off lights so another motorist doesn’t mistakenly drive into you.

Car maintenance is important to safe driving in foggy weather. Motorists are advised to: 

• Make sure windshield wiper blades are in good condition. Streaks or skipping on the vehicle's windshield are signs of worn wiper blades. Many crashes occur because motorists couldn’t see out of smeared windshields.

• Keep headlights and taillights working and lenses clean. This vehicle equipment is critical to help you see and be seen by other drivers in foggy and also normal driving conditions.