GMC 1999 Sierra 1500 Pickup Owner's Manual page 230

Your Driving and the Road
Winter Driving
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AM480004
Here are some tips for winter driving.
Have your vehicle in good shape for winter. Be sure your engine coolant
mix is correct.
Snow tires can help in loose snow, but they may give you less traction
on ice than regular tires.
If you do not expect to be driving
in deep
snow, but may have to travel over ice, you may not want to switch to
snow tires at all.
You may want to put winter emergency supplies in your vehicle.
Include an ice scraper, a small brush or broom, a supply of windshield
washer fluid, a rag, some winter outer clothing, a small shovel, a flashlight, a
red cloth, and a couple of reflective warning triangles. And, if you will be
driving under severe conditions, include a small bag of sand, a piece of old
carpet or a couple of burlap bags to help provide traction. Be sure you
properly secure these items in your vehicle.
Driving on
Snow
or Ice
Most of the time, those places where your tires meet the road probably have
good traction.
However, if there is snow or ice between your tires and the road, you can
have a very slippery situation. You'll have a lot less traction or "grip" and will
need to be very careful.
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