BOSTON (TheStreet) -- You won't freeze to death if your car breaks down during a summer driving vacation the way you might in winter, but other dangers abound -- so here are some key emergency items to carry on your trip.
"A severe breakdown during the summer can be an inconvenience at the very least, and a risk to your life at the worst," says Mike Calkins, an ASE-certified master auto technician and national technical-services manager for AAA. He says that while you won't get stuck in a snowbank or skid on ice this time of year, hot summer weather can do a number on plenty of your car's systems, from the radiator to the tires.
"If you take a car with underinflated tires, load it up with family members and all of the stuff that you take on vacation and drive it on hot pavement in high temperatures, the tires can easily overheat and blow out," Calkins says. "That's not something you tend to see in the winter."
Read on for a look at a few things that the expert recommends everyone take on driving vacations this summer in case of emergencies, along with tips for where to buy them and approximately how much to pay.
Cellphone, car charger and a spare battery
"A cellphone is your No. 1 line of defense today if your car breaks down," says Calkins, who recommends preprograming your phone with the number of a roadside repair service such as AAA's (800-AAA-HELP).
He also advises carrying an adapter that will allow you to charge your phone's battery via your car's cigarette lighter. These cost as little as a dollar or so, and you can find them everywhere from big-box retailers to drugstores these days.
Calkins also suggests buying an a spare external battery pack for your phone and throwing it in the glove box for emergencies. These widely available devices typically cost between $10 and $80 and will power up your phone or other electronic devices for an hour or more.
Emergency food and water
Carrying water can literally mean the difference between life and death if your car breaks down in a remote area during summer heat.
"You definitely need to have enough water on hand for you and your passengers -- and if you're traveling with a pet, keep them in mind too," Calkins says.
The expert says how much water to carry depends on how far off the beaten path you plan to go.
"You can probably get by with nothing if if you're traveling from one side of Los Angeles to another -- but if you're going from L.A. to Bakersfield, that's a different story because you're going to be in the middle of nowhere for a while," Calkins says.
He also recommends having some dried fruit, packaged nuts and/or energy bars on hand to provide food in case you're stranded on the roadside for a while.
Calkins suggests drivers with enough do-it-yourself know-how to change tires carry a tool kit, tire-pressure gauge and/or x-bar lug wrench (those four-pronged tools that look like big crucifixes).
"The lug wrenches that come with [cars' spare tires] aren't that big or strong, so I like the big x-bar wrenches," he says. "There's really no substitute for them when you have a flat tire."
X-bar wrenches typically cost around $10 to $30, while emergency toolkits run about $15 to $50 and tire-pressure gauges range from roughly $2 to $20.
While many consumers can change flat tires, Calkins recommends calling for help rather than trying to fix an overheated engine yourself, as those who try to add coolant to hot radiators run the risk of serious scalding.
He says overheated engines can also suffer permanent damage if not addressed quickly and properly. "Today's engines have got a lot of aluminum components that are built to very tight tolerances and can warp pretty easily," Calkins says.
Emergency flares and reflective triangles
Flares or reflective triangles cost almost nothing to put down on the road when your car breaks down, but can save you and your family from potentially fatal accidents.
"It can really ruin your whole day if you have a breakdown by the side of the road and someone plows into you," Calkins says.
Most emergency-repair kits come with flares and/or reflective triangles in addition to tools. You can also buy flares as stand-alone items for around $3 to $5 for a three pack, while triangles cost about $10 apiece (although they're often sold in multi-packs).