Buick 1993 Roadmaster Owner's Manual page 182

Driving in Fog, Mist and Haze
When you drive into a
fog
patch, your$sibility will be
reduced quickly. The biggest dangers
are
striking 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 clear or, 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 derise fog may extend only for a few feet
(meters) or for miles (kilometers); you can't really tell
while you're
in
it.
You
can only treat 'the situation with
extreme tare.
One, common fog condition - sometimes called
m i s t
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 dip into 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 see through it for several
hundred feet (meters). Or-it might he 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.