Because of the limited space in automobiles, storing water must be in small packages. You may have plenty of food and water, but if you're cold you'll feel miserable. Especially in the winter, warmth is a must for an auto 72 hour kit. If you get stranded on a desolate road or stuck in a snowstorm, you will be glad you have a source of warmth in your car. Also, for shelter from the rain, include a poncho or other rain gear.
Warm packs are nice for quick, concentrated heat.
You can put them in your pockets, shoes and gloves to stay warm. Wool is one of nature's warmest fibers. It provides warmth even when it's wet. It is best to get a wool blend blanket because when synthetic fibers are added to it they provide softness, washability and durability. Emergency blankets and bags are lightweight and fold to pocket size.