I think that if you don't have winters on, and you rear-end someone who does, there should be an additional fine for not having the right vehicle set-up for the conditions - vehicle set up is as important as driver ability in crappy weather I think.
(Full disclosure: "Winter" is a new concept to me, so you need to take my opinions on the subject with a grain of salt - actually, scratch that, we need the salt for the roads).