Several years ago there was a national tragedy here in Pennsylvania where a simple snow storm caught too many people on a major highway that emergency responders were not able to get to all of them. There were so many cars and so much snow on the ground that plowing was impossible. People sat in their cars waiting for help as the snow piled deeper and deeper. Something like this caught everyone off guard and there were politcal fallout from it, but, the real problem was nobody had any backup plan for this and they should have.
I’m a big fan of keeping emergency survival blankets in my car because people don’t realize that sitting in a car and idling is only going to give you about 8-12hrs of heat and energy and then you will have lost your heat source. Something like the recon sleeping bags like the recon 2 are all you need for a basic SHTF car break down where you might be better off using that an waiting for help rather than depend on your car heater keeping you warm. The Recon 2 is so small that it hardly takes up any room in your trunk and is a great investment.