Begin by filling your glove compartment. Obviously, this is where you will stash your registration and proof of insurance. Purchase a compact LED flashlight and keep it in the glove compartment. Many people put flashlights in the trunk but if you can't see to get to it, the flashlight does you no good. Folded local and national road maps (depending on the length of your trip) and a compass will fit into your glove compartment with ease, as will note pads and a pen (for leaving a note about your whereabouts). If your compartment locks, place about $20 to $40 in an envelope and keep it there.
Keep your car charger in the side pocket of the driver's side door. You should always plug your phone in right as you leave so that it charges while you're driving. This way, if you are in an accident, your phone will already be charged. Having a phone that is already charged can be a life saver, especially if your car battery dies.
Use the space underneath the front seats of your car to store smaller emergency supplies. You could place up to six medium to large snack bags or freezer bags full of supplies in this area. When filling your bags, keep similar items together. For example, one bag could be full of batteries, matches and/or a lighter and a Swiss army knife. Fill another with calorie or nutritional bars.
Fill the spare tire well with as many small and flat items as possible. The size of the well will vary based upon your vehicle but you should obviously have at least a tire and a jack in the well. You should also be able to fit at least one flare in your spare tire well.
Buy two duffel or gym bags and fill them with your clothing items. You should have two of everything, including shirts, sweatshirts and pants. Pack a few more pairs of socks and underwear since these are small items. You should also be able to fit a pair of comfortable outdoor walking shoes in one of the bags. Use the bags instead of containers as the containers will slide around in your trunk while you drive. This can be very annoying.
Place two to three warm blankets inside of your trunk. Since these can lay relatively flat if folded just once, you can lay them down directly in your trunk instead of putting them in a bag.
Keep a 12-pack of bottled water in your trunk at all times. Water is the most important supply to have in any emergency where you are trapped for several hours or even days. If you are traveling with a larger group of people, buy a 24-pack of water specifically for that trip.
