1993 Buick Park Avenue Owner's Manual - Page 188

Driving in Fog, Mist and Haze r When you drive into a fog patch, your visibility will be reduced quickly. The biggest dangers arestriking the vehicle ahead or being struck by the one behind. Try to "read" the fog density down the road. If the vehicle ahead starts to become less clearor, at night, if the taillights are harder to see, the fog is probably thickening. Slow down to give traffic behind you a chance to slow down. Everybody then has a better chance to avoid hitting the vehicle ahead. A patch of dense fog may extend only for afew feet (meters) or for miles (kilometers); you can't really tell while you're in it. You can only treat the situation with extreme care. One common fog condition -- sometimes called mist or ground fog -- can happen in weather that seems perfect, especially at night or in the early morning in valley and low, marshy areas. You can be suddenly enveloped in thick, wet haze that may even coat your windshield. You can often spot these fog patches or mist layers with your headlights. But sometimes they can be waiting for you as you come over a hill or dipinto a shallow valley. Start your windshield wipers and washer, to help clear accumulated road dirt. Slow down carefully. Fog can occur with high humidity or heavy frost. It can be so mild that you can seethrough it for several hundred feet (meters). Or it might be so thick that you can see only a few feet (meters) ahead. It may come suddenly to an otherwise clear road. And it can be a major hazard.