1993 GMC Suburban Owner's Manual - Page 208

AN459006 Fogcanoccurwithhighhumidityorheavyfrost. It can be so mild thatyou it might be so thick canseethrough it forseveralhundredfeet(meters).Or It maycomesuddenly to thatyoucanseeonlya fewfeet(meters)ahead. anotherwiseclearroad.And it can beamajorhazard. will be reducedquickly.The When you driveintoafogpatch,yourvisibility biggestdangersarestrikingthevehicleaheador being struckbytheone If thevehicleahead behind. Tryto "read"thefogdensitydowntheroad. starts to becomelessclear or,atnight, if thetaillightsareharder to see,the fog is probably thickening. Slow down to givetrafficbehindyouachance to slow down. Everybody thenhasabetterchance to avoid hitting thevehicle ahead. A patch of densefogmayextendonlyforafewfeet(meters)orformiles (kilometers); you can'treally tell whileyou're in it. You canonlytreatthe situationwithextremecare. Onecommonfogcondition-sometimes called mistorgroundfog-can happen in weatherthatseemsperfect,especiallyatnightor in theearly morning in valleyand low, marshyareas. You can be suddenlyenveloped in thick, wethazethatmayevencoatyourwindshield. You can often spotthese fogpatches or mistlayerswithyourheadlights.Butsometimesthey can be waitingforyouasyoucomeovera hill or dip into ashallowvalley.Start yourwindshieldwipersandwashertohelpclearaccumulated road dirt. Slow downcarefully. 440