Driving in fog

Fog creates dangerous driving conditions. It reduces visibility, makes it hard to spot hazards, and it becomes difficult for a driver to judge distance. The unusual weather condition can create optical illusions. Drivers may misjudge their own speed or have a hard time determining if other cars are moving.

Fog is a cloud formation near the surface of the earth. It's common near lakes and the coastline in the morning or evening. It can form at other times and other places. Check your local weather forecast before driving.

When possible, do not drive in foggy conditions. Dense or light fog is a major cause of accidents, including pile-ups. If you cannot avoid driving in fog, here are some tips to ensure safe driving.

• Fog lowers visibility. You may not see objects in front of you until they are too close. Reduce your speed, and increase the following distance to give yourself more time to react. Avoid bunching up near other cars, even if it feels like it improves visibility.
• Do not use cruise control and be prepared to brake quickly.
• Be sure to check your speedometer regularly. Fog can create the optical illusion of driving slowly. This causes many drivers to speed up. Don't rely on your eyesight, but check the speedometer instead.
• Be patient while driving in foggy weather. Brake slowly to give other vehicles a chance to react. Turn on your signal lights early to provide plenty of notice. As the road is obscured, avoid passing other cars.

• Fog can get thicker without warning. If visibility gets too low, be sure to pull off the road. Find a parking lot or driveway where you can safely pull over. If necessary, drive far off the shoulder of the road or onto a grassy area. Move a reasonable distance away from the main roadway.
• Keep your hazard lights on but turn off headlights; this allows other drivers to see you but avoids looking like you're still moving.
• It's best to avoid the dangerous weather. Do not drive until visibility improves. Try to find shelter away from your car. If you must remain in your vehicle, then keep your seatbelt on.

• Turn on your rear fog lights. They improve your visibility to other drivers. In dense fog, you can also turn on your hazard lights or flashers.
• If your vehicle has fog lights or driving lights, turn them on. Fog lights use a color and position that avoids the glare created by a headlight.
• You should only use the low beam headlights. Do not use high beam headlights. High beams get diffused and reflected by the water droplets in the fog, making it harder to see.

• Driving safely in fog requires paying careful attention to your surroundings. Reduce all distractions. Turn the radio off. Ask your passengers to be quiet and watch for obstacles.
• It's easy to drift out of your lane while driving in fog. Watch the lines on the road or stay on the right side of the road to ensure that you stay in your lane. Do not change lanes or pass other cars. Be aware of the position of oncoming traffic.
• Open your window a bit to hear outside; this improves awareness of things near your car.           
• Be prepared to stop rapidly. Vehicles, people and bikes can appear from nowhere. Some animals also feel bolder in the fog and may enter the roadway.
• Moisture will buildup on the windshield and windows in foggy conditions. Keep them clear by using windshield wipers and defrosters. Adjust their settings as the conditions change.