I long ago developed a method for determining the safe speed in snow: slowly accelerate until you feel the rear wheels slip (it feels like your rear legs have been kicked out from under you) and then back off. From my old '75 Honda Civic this was about 45 mph in wet snow over car-packed snow. But you have to do it each and every time, because conditions are different every time you drive on the stuff.

Truebit, learn to use the cruise control but NEVER NEVER NEVER use it in snowy or icy conditions! I learned this the hard way when passing an 18-wheeler on the Indiana Toll Road once -- doing a 180 while next to a big truck is pretty exciting, lemme tell ya! About two days later I read a bit in the paper that told me what I had just learned the hard way.