First aid is all about being prepared, whether at home, at work, or on the road. And although good car maintenance will help to prevent breakdowns, there's still the possibility that car trouble or bad weather may cause you to be stranded for a few hours, or even a few days. An emergency car kit, either purchased pre-packaged, or self-customized, will help to ensure your safety. The essential supplies to have in your car include:

Water
You can live for days, even weeks, without food. But you won't survive for very long without water. Look for emergency water pouches rather than bottled water; they'll take up less room. And check for water with a long shelf life.

Food
Look for high calorie energy bars with plenty of protein and carbohydrates, with a long shelf life and the ability to withstand hot and cold temperatures. Avoid salty foods that will increase your thirst and diminish your water supply too rapidly. Store food supplies in a hard plastic container.

Extra Clothing
A rain jacket is good year round; add seasonal clothing such as hat, scarf, and gloves as appropriate.

Blankets
One or two wool blankets will provide warmth if you need to spend the night in your car. A space blanket or bag is best for cold weather conditions. These are made of reflective material that will absorb as much as 80 percent of your radiant body heat and keep you warm even in the winter.

Flashlights
Two durable flashlights with extra batteries will light the way if you need to go for help, illuminate your view under the hood of the car, and also serve as hazard lights. Look for high power LED flashlights with a long run time.

Tools
Of course, you're going to have jumper cables and equipment for changing a flat tire. But it's good to include a basic tool kit, a knife, and a collapsible shovel for shoveling your way out of the snow or mud.

Cell Phone and Charger
You won't always be in a location where there's a signal. But if you are, you can summon help. You may also want to invest in a wind up cell phone charger.

Medications and Medical
Supplies If you take daily prescription medications, bring enough for several days. And if you use medical supplies such as a glucose meter, take it along.

First Aid Kit
A basic first aid kit with a first aid instruction chart or book will help you to treat minor injuries and illnesses.

Make sure to check and restock your emergency car kit at least once each season to make sure that you have everything you need.