>>While in Virginia I got scared each time there was snow on the pavement, because the total amount calculated as total horsepower times tons of iron divided by average IQ of the drivers divided by their cumulative experience in driving on snow is a number larger by a few orders of magnitude than what I was used to. Just 2mm of snow and I'm happy that american roads are so wide and the crossroadses so big, so the idiot on the other side can waltz his four-liter truck far away from me. They may have heard that they should go light on the pedals while on snow, but the distance between the ears and the brain is quite big, it takes a lot of time for the content to arrive.
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>Winter tires and 4wheel drive go a long way.

If you know what you're doing. But in coastal Virginia there are about four days of snow each winter, so nobody has winter tires. OTOH, 4wd will often get you the short way into the ditch, specially if you think 2mm of snow is negligible and step on it. Daughter would frequently drive on I64 there, at the regular 60kmh or thereabouts, and would frequently be passed by personal tanks with 4l engines. "See you later" was the self-fulfilling prophecy, those guys wouldn't get far.