What Goes Into the Trunk (and What Doesn't)
Your car's trunk is one of those spaces that can slowly become a dumping ground for everything from groceries to gym bags, and most of us don't think twice about what we've left back there. But certain items can be damaged, dangerous, or even prohibited to store in a vehicle, so it's worth knowing what you can and can't keep in the back of your car. Here are 10 things you should stop leaving in your trunk—and 10 you always can (and should).
1. Medications
Most prescription and over-the-counter medications are sensitive to heat, and a trunk can reach temperatures well above 100°F on a warm day. Prolonged exposure to those conditions can break down the active ingredients, making your medication less effective or even unsafe to take. Keep your prescriptions stored at home or in a climate-controlled bag if you need them on the go.
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2. Sunscreen
It might seem logical to keep sunscreen in your car so it's always within reach on sunny days, but the heat can degrade the formula faster than you'd expect. Once sunscreen breaks down, it won't provide the SPF protection listed on the label, which means you're not getting the coverage you think you are. Store it in a cool, dry place at home (yes, even the extras—no stocking up in your trunk) and transfer it to your bag when you know you'll need it.
3. Aerosol Cans
Hairspray, spray paint, and other aerosols contain pressurized contents that can become extremely dangerous when exposed to high heat. In a hot trunk, the pressure inside the can can build to the point of explosion, which poses a serious risk to anyone nearby. These items should always be stored at room temperature in a garage or cabinet, never in a vehicle.
4. Electronics
Laptops, tablets, and external hard drives are all vulnerable to heat damage that can corrupt data or permanently disable the device. Batteries in particular can degrade or swell when left in high temperatures for extended periods, which creates both a performance issue and a safety hazard. Take your devices inside with you rather than leaving them to bake in the back of your car.
5. Groceries
Perishable food items left in a hot trunk can enter the temperature danger zone where bacteria multiply rapidly, putting you at risk of food-borne illness. Even a short trip with meat, dairy, or prepared foods can become a problem if you make extra stops along the way. Plan your errands so grocery shopping is your last stop, and get those items home and refrigerated as quickly as possible.
6. Important Documents
Passports, Social Security cards, and vehicle titles should never live in your trunk because vehicles get broken into far more often than homes do. Losing those documents can mean weeks of bureaucratic headaches to replace them, and in some cases, they can be used for identity theft. Keep sensitive paperwork locked in a secure location at home, such as a fireproof safe.
7. Lighters and Matches
Fire-starting tools are genuinely hazardous when left in a hot car, as extreme heat can cause lighters to leak butane or even ignite unexpectedly. The risk might seem small on a mild day, but summer temperatures inside a parked vehicle can reach dangerous levels within minutes. Always carry lighters in your pocket or bag rather than stashing them in the trunk.
8. Wine and Beer
Heat spoils alcohol faster than most people realize, and wine left in a hot trunk can turn in a matter of hours. The expansion caused by heat can also push corks out of wine bottles or cause beer cans to leak or burst, which makes for a pretty unpleasant surprise. If you're transporting bottles, go directly to your destination and keep them out of the sun.
9. Pets
This one should go without saying, but it's worth stating plainly: never leave an animal in a trunk or a locked car in warm weather. Temperatures inside a vehicle rise at an alarming rate, and animals can suffer from heat stroke and die within minutes. If you're running errands and can't bring your pet inside with you, leave them at home where it's safe.
10. Paint Cans
Paint is more vulnerable to temperature extremes than most people realize, and storing cans in your trunk can cause the formula to separate, thicken, or dry out entirely. If the can has already been opened, the repeated heating and cooling cycle can compromise the seal and lead to leaks, which is a mess you definitely don't want to deal with in your vehicle. Store paint in a climate-controlled space like a basement or utility room where the temperature stays relatively stable year-round.
So, what are some things you can leave safely stored in your car trunk? Here are 10 things you won't have to worry about.
1. A Spare Tire and Jack
A flat tire is one of the most common roadside emergencies drivers face, and having the equipment to handle it yourself can save you a long wait for roadside assistance. Your spare doesn't have to be a full-size tire since a compact spare, also called a donut, will get you to a shop safely. Just make sure you check the spare's air pressure every few months so it's actually ready when you need it.
2. Jumper Cables
A dead battery can happen to anyone, whether you accidentally left a light on or your battery is simply aging out, and jumper cables let you get back on the road without waiting for help. They don't take up much room, and a decent set of cables will last for years without requiring any maintenance. Keeping a pair in your trunk means you can also help out a fellow driver who's stranded in a parking lot.
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3. A First Aid Kit
Minor accidents, cuts, and injuries can happen anywhere, and having basic medical supplies on hand means you don't have to improvise with a napkin. A compact first aid kit with bandages, antiseptic wipes, and pain relievers takes up very little space and covers a wide range of common situations. Many pharmacies sell pre-assembled kits that are perfectly sized for a glove compartment or a corner of your trunk, though we think it's best stored somewhere you can easily reach.
4. Reusable Shopping Bags
Reusable bags are one of those items that are only useful if you actually have them with you when you shop, and stashing a few in your trunk solves that problem entirely. They're lightweight, fold down to almost nothing, and can handle far more weight than a standard plastic bag. Having them within reach also means you won't find yourself standing at the register trying to decide if you really need to buy yet another bag.
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5. Emergency Reflective Triangles or Flares
If your car breaks down on the side of the road, visibility is one of the most important factors in keeping you safe while you wait for help. Reflective triangles and road flares alert other drivers to your presence, especially in low-light conditions or on curves where your vehicle might be difficult to see. Both options are inexpensive and compact enough to tuck into a corner of your trunk without taking up any meaningful space.
6. An Ice Scraper and Snow Brush
If you live somewhere that gets snow or freezing rain, an ice scraper is a non-negotiable item to keep in your vehicle year-round, because winter weather has a way of arriving when you least expect it. Trying to clear your windshield with a credit card or your bare hands is both ineffective and miserable, and driving with impaired visibility is genuinely dangerous. A good-quality scraper and brush set costs very little and takes only seconds to find when the season changes.
7. A Blanket
A compact emergency blanket or even a regular throw blanket is a smart thing to keep in your trunk, particularly if you live in a region where temperatures drop significantly at night. If you're ever stranded in cold weather waiting for a tow truck, having something to stay warm with can make a frustrating situation a lot more bearable. It doubles as a useful item for tailgates, picnics, or anytime you want a little extra comfort on an outdoor adventure.
8. Windshield Washer Fluid
Running out of windshield washer fluid at the wrong moment can make driving surprisingly difficult, especially on roads where grime, salt, or bugs are an issue. Keeping an extra jug in your trunk means you can top off your reservoir whenever you notice it getting low, without having to make a special trip to the store. It's one of those small conveniences that costs almost nothing but proves its worth the moment you actually need it.
9. A Change of Clothes
Keeping a spare outfit in your trunk is one of those things you'll forget about entirely until the day something spills on you, or you need to go somewhere unexpectedly after the gym. A basic set with a fresh top, pants, undergarments, and a pair of socks doesn't take up much room, especially if you roll everything up and tuck it into a small bag. It's the kind of low-effort prep that feels unnecessary right up until the moment it saves you from a genuinely awkward situation.
10. Basic Tools
A small toolkit with a multi-tool, zip ties, duct tape, and a few basic wrenches can be a real lifesaver for minor fixes that don't require a mechanic. Loose hose clamps, a dragging bumper, or a rattling panel are all things that can be temporarily addressed roadside with the right tools on hand. You don't need to pack an entire toolbox since a modest selection of versatile items will cover the vast majority of minor automotive headaches.
