It's inevitable: Cars break down. In fact, the Automobile Association of America, the largest emergency roadside assistance organization in the country, handles between 29 and 30 million roadside calls for help each year from motorists stranded on America's highways and byways. While most mishaps can be handled with little trouble (AAA says that 3 out of 5 assistance calls it receives are fixed on location without the need for a tow), others are a little trickier because aid isn't nearby or is "closed for the evening." Waiting time for a helping hand to arrive in these situations varies greatly depending on where you are, as well as on road and weather conditions.

It's important to follow the Boy Scouts' motto while on the road: Be prepared! That means putting together an emergency road kit and carrying it around with you.

Watch Video: How to Prepare for a Roadside Emergency

The simple solution

For those who want to take the thought process out of building a kit on your own, there are plenty of prepackaged auto safety kits on the market. The manufacturers have done all the thinking for you, but they are predominantly "get back on the road" type of kits, serving as a good foundation for you to personalize.

For instance, a kit from Justin Case includes a flashlight, two D-cell batteries, a polyester blanket, emergency poncho, 12-volt air compressor, 12-foot jumper cables, 12-foot tow rope, two bungee cords, a stainless multitool, a pair of latex gloves, a roll of duct tape and a 54-piece first aid kit.

Some prepackaged kits have more tools, some more medical supplies; some are aimed at winter and some are more survival-based. Prices range from around $30 to $85.

Bing: Find a Car Emergency Kit

Do it yourself

Creating your own kit is the best way to make sure you have everything you need if stranded. Picking a bag or container is the first step to making your own kit. Consider putting Velcro on the bottom of the bag or container to keep it from sliding around in the trunk. The best thing about the DIY kit is that you can tailor it to your specific needs, taking into account the number of people in your family, the climate where you live and your mechanical capabilities. It may make sense to put together a kit for the driver and a special, secondary package with key items for the rest of the family. The secondary kit can be packed with baggage when the family goes on an extended road trip.

Read:  How to Handle a Real Auto Emergency

The basics

Whether you are simply trying to get back on the road after a blowout or trying to survive a night in the elements because your transmission seized in the middle of nowhere, there are a few must-have items for every emergency kit that can make the experience of getting stranded palatable — or at least survivable.

The first two are easy: a collection of basic tools and an easy-to-follow automobile fix-it guide — that is, if you don't have grease in your veins and can't strip down an engine in your sleep. These items will probably keep a minor problem from stranding you on the side of the road for very long and will get you to a fully stocked repair shop or auto parts store for a more complete repair job.

The following items might be the difference between spending a few inconvenient hours away from civilization and your passengers measuring you up for the Donner Party treatment until help arrives.

Read:  15 Patchwork Repairs

Food

Fresh fruit and deli meat are probably not ideal for long-term storage, but survival food bars can provide the caloric intake you need to keep your strength up and hunger pains from driving you nuts. Rated in the 200- to 400-calorie range, high-calorie fitness bars are a few steps below emergency food rations but provide ample long-term energy. The bottom line is that a box or two of your favorite granola bars will easily fill short-term needs. Remember, nonperishable items that are individually packaged will last longer.

Bing: Stock Up on Survival Food and MREs

Water

Water is essential for survival. The choice here is how much to pack: a few one-liter bottles or a family-style 2.5-gallon water briefcase? Space is the limiting factor. Freshness is also a concern, so be prepared to swap out both water and food items. You can do it quarterly on the equinoxes and solstices, or semiannually on New Year's Eve and the Fourth of July.

Do you carry an emergency roadside kit in your vehicle?