What about the tires? I accidentally drove home in a snowstorm tonight. Last two miles were pretty slippery. Maybe it would have been just as bad in another car, but those low rolling resistance tires aren't very grippy anyway.
We briefly had piston-free garage with an FFE and a Mazda RX8. But since they both have serious limitations as winter cars, I just traded the rx8 in on a Fiat 500 Abarth.
50-60 is what I get in Maryland on a cold day. Beside needing to run the heat and maybe taking a battery hit, I think the headlights are a factor too. I generally do better on the daylight trip in than coming home in the dark. I have a 60 mile commute --good thing I can charge at work.