If it's that bad, the biggest trouble spot is likely the big hill right at the edge of town, and I can always carry the bike up that and treat most of the rest of the trip as a really unstable sled ride. :D
I have thought about studded tires, but really for the 2-3 days a year it tends to ice up here, I could either ask the boss to pick me up in his 4x4 (not that I think it has a better chance of getting to the office, but then it's his fault if I don't make it in) or call in sick.
Seriously, there have been plenty of times when I had a car, that if my legs had been in the shape they are now, I'd have ridden the bike then, just for the ability to push or carry it through the bad spots. The tread on the Gavin MTB shoes I ride in is just about as good as you're going to get for light-to-medium ice, short of actual crampons. (Now there's a thought; get some old pedals, put spikes on the bottom and make SPD compatible crampons for ice riding.)