Anyone who lives in a place that gets snow during the winter should keep a sand shaker in all their vehicles. All it takes is a little ice or slick, packed snow and you may be stuck. To get moving again simply shake a little sand under you drive tires and along the path you want to take and drive out. This doesn't work all the time but it is surprising how a little sand solves the spinning tire problem.
To make a sand shaker simply save a plastic container with a screw-on lid. I like grated Parmesan containers since they have a snap lid. Fill whatever container you have with dry sand and put it in your trunk. Make sure the sand is dry or you may have a frozen mass of sand when you need loose grains.
If you have enough containers and sand, give sand shakers to family and friends to put their vehicles. Carry a spare and pass it on to anyone you see who needs one.