A car is not the place to be in a cold weather emergency. To be on the safe side, your trunk should be equipped with an emergency kit that contains the following items:
Emergency First Aid Kit
Extra clothing, blankets and large plastic bags for warmth.
Blackboard eraser for foggy windows
Non-perishable snacks like granola bars, peanuts and dried fruit
De-icer spray for frozen locks or to loosen lug nuts to fix a flat tire
Ice scraper and snow shovel
Sand or cat litter for traction
Supply of change
Cellular phone and charger
Flashlight with extra batteries or a wind up flashlight/radio combination
Don't rely on your vehicle's electrical system for light. You will want to conserve the car's battery as much as possible so have a working flash light.
A hat. Experts say that up to 40% of your body heat can be lost through the head. A few inexpensive hats in your kit can make a big difference.
Location, location, location. To eliminate the dangers associated with getting out of a car and since rear collisions may result in trunk damage, MCFRS recommends that you place your emergency kit in the passenger footwell where it is easily accessible to the driver however won't become projective in a collision.
Filled Gas Tank. You should also keep your gas tank as full as possible. If you are stuck in a storm, start the car and run it for only ten minutes of every hour to keep it warm enough yet safe from poisoning.
Ventilation: The American Red Cross site also recommends keeping slightly ajar a window on the side on which the wind is not blowing.
Whistle: A plastic whistle can alert rescuers to your presence.