Take black ice out of the picture.

Automotive Tip fo the Week: Last one on tires for a while I think/hope. Snow tires are a bit of a misnomer. Ice/cold tires or simply "winter" tires is really a better description. While they improve snow traction the biggest gains are in cold and ice traction. Continental released data on their tires a couple years ago saying "anytime below 45°F use a snow tire" showing the increase in braking performance and cornering forces. The difference can be greater than 20% just for regular (no ice/snow) braking! On top of that the wet and ice traction are hugely better. Personal anecdote that illustrates this: two winters ago we got freezing rain and I live near a hill I drive every day. I pulled out on to the hill and had to stop. A 4WD Jeep Cherokee with all season tires was struggling and slid over sideways in to the curb. I let go of the brakes accelerated slowly and passed them. On the hill. I drive a RWD car with snow tires and no limited slip differential. This happens at stop lights and the like throughout the winter. I stop and start without issue, other people often struggle or slide about. It's not about having the tires for snow, it's about having them for traction on all the days there is black ice, packed snow, and leftovers from the plow which seems like more days than not! Also, while the initial investment is not small, one minor fender bender and your insurance deductible will have paid for the tires. Additionally, getting 4-5 years out of a set of snow tires is not abnormal since people drive a little less in winter and you only run them for about 5-6 months. Your summer tires last longer then too. I know I'm thankful for the tires at least a half dozen times every winter. If you are curious about tests comparing snow tires to regular tires tirerack.com has a few and it shows how big the difference really can be. Remember, it's not so much about driving in snow, but driving in the cold and on ice you may not see.