if you have that much snow and drive so much, i would consider getting dedicated snow tires. It may cost a little extra up front, but it would save wear on your summer tires, and it is way cheaper than getting in an accident
four 195/60R15 General Altimax Arctic for 2005 Ford Focus mounted on new steel wheels.
492$ + shipping (probably about another 50-100$)
just the tires is ~300$
May 2014 ROTM, June 2015 ROTM
for auto-x: '04 Liquid Grey ZX3
for street: '02 Infrared SVT