Speaking of windshield wipers, it's a good idea to make sure your washer fluid reservoir is filled up and maybe that you have an extra bottle in the trunk. Chemicals and salt on the roads can gunk up windows quickly, so you'll be using more than usual if your commute is extended. Some other stuff to keep in your trunk for the winter? A small snow shovel, a flashlight with fresh batteries, a blanket, extra clothing, and some nonperishable food like granola bars and bottled water. And of course, keep your cell phone fully charged.