I think all of you are missing a central point to BicycleCrazy's post. Studs on your bike can make riding a bicycle in ice conditions ("black ice" is an over used term) possible. But studs do nothing for the cars that are around you. They don't even make it easier to get out of the way.
When it 'frizzles' (freezing drizzle) around here, it's time to take drive or take the bus. Being the 8 ball in a game of automobile billiards isn't good for preserving your 3rd dimension. Snow? I'll ride. Frizzle? Nope.