The most obvious is: know a major storm is coming, stay home, or at least stay off the roads if at all possible. My DW and I have an understanding that a surprise blizzard or ice storm makes it okay to grab the closest hotel for the night.

Have some cold weather gear within reach of the driver. If you've lost the road and hit a power pole, you may not be in a condition to worm your way into the trunk. A queen size fleece blanket fits neatly behind the passenger seat. Better still, dress for the conditions and keep your car cool. What you're wearing may be all you have, and insulation works even when you're unconscious.

And IMO: unless you live in a place where people automatically shoot first and ask questions later, knock on the door of the nearest house, stand well back so you're no immediate threat, and ask them to call 911. People are generally better than you may have heard.