Roadside Emergency Kit: What Belongs in Every Car Before Winter

The jack in your trunk has never been used. Neither has the spare, if you still have one. That's how cars work now: you drive for years, nothing happens, and then a tire goes flat on a county road with no shoulder and the temperature is falling.

A roadside emergency kit isn't a shopping list. It's a short set of answers to three problems: get the car moving again, stay warm if it won't move, and don't get hit while you work out which one you're in. Mid-October is the honest time to do it, because the first storm is a bad place to learn what you forgot.

What actually strands people on the side of the road?

Boring mechanical failures, not disasters. AAA handled over 27 million emergency roadside service calls in 2024. About 13 million were tows and about 7 million were battery issues, close to 74 percent of everything they did. An earlier AAA breakdown put battery failure, flat tires, and lockouts at 17 million calls in one year, and found two-thirds of Americans had never had a battery tested before it failed.

Crashes are the other half. NHTSA's 2023 crash summary counts an estimated 6,138,359 police-reported crashes, 2,442,581 people injured, and 40,901 killed. Weather is a steady slice: FHWA puts the five-year average at 744,911 weather-related crashes a year, about 12 percent of all crashes, with 3,807 killed.

So build for the common case. Your kit will get used on a dead battery in a parking lot, not in a whiteout. It just has to work in the whiteout too.

What is the real danger if you get stuck in a car overnight?

Cold and carbon monoxide, not hunger. You can skip meals for a day without consequence. A car with the engine off is an uninsulated metal box, and the engine that keeps you warm is also making exhaust.

The National Weather Service gives the rule plainly: "Run the motor about 10 minutes each hour for heat," "open the window a little for fresh air," and "Clear snow from the exhaust pipe to avoid gas poisoning." Maine Emergency Management adds the detail most people miss: keep one window cracked anyway, "as heavy snow and ice can seal a vehicle shut." Minnesota's Department of Public Safety says the same about clearing the tailpipe.

CO has no smell and no color, and CDC says the symptoms get mistaken for the flu: headache, dizziness, weakness, confusion. More than 400 Americans die each year from unintentional CO poisoning not linked to fires. An honest limit: CDC doesn't break that total out by vehicle, and no federal agency we found publishes a yearly count of people who die of cold or CO inside a stranded car, so we won't invent one. The same physics applies at home, which is why we wrote up carbon monoxide safety around a running generator.

Should you stay with your vehicle or walk for help?

Stay, in almost every case. Maine puts it best: "Stay with your vehicle unless you know exactly where you are, how far it is to possible help." A car is shelter, a windbreak, a heat source, and a large object search crews can see. You're none of those on foot in the dark.

Three things flip it: you can see the help rather than believe in it, the car sits somewhere unsafe (a travel lane, a blind curve, rising water), or someone is already coming. If you stay, make the car findable. NWS says raise the hood once the snow stops. Maine suggests a bright cloth on the antenna, and Minnesota's kit list includes a red bandana for that. Our longer walkthrough covers exactly what to do if you are stranded in your car during a blizzard.

What is the most dangerous part of a roadside breakdown?

Standing next to the car. AAA reports that since 2015, more than 1,600 people have been struck and killed outside a disabled vehicle, plus an average of 24 roadside responders a year. Move Over laws exist in all 50 states and the District of Columbia, but 23 percent of surveyed drivers didn't know their state had one. Visibility is the first item in the kit, not an afterthought.

1. Get fully off the road first. A flat tire is cheaper than a car. Roll it to the shoulder or an exit on the rim if you have to.

2. Hazards on before you stop, so traffic behind you starts reacting early.

3. Exit on the traffic-free side. Climb across the seats if you must.

4. Stand behind the barrier, up the embankment or behind the guardrail, well behind the car. Not in front of it, which is where a struck vehicle gets pushed.

5. Set reflective triangles, one close and one farther back, farther still on a highway or a curve.

Triangles beat flares for most drivers. They work for hours in rain, can't start a grass fire, and don't expire in the trunk. Flares are brighter through fog and heavy snow, but they burn out, they're a fire risk around spilled fuel, and some states restrict them. Add flares only if you drive rural highways in fog country.

What belongs in a roadside emergency kit?

Six tiers, each solving one problem. Build tiers 1 and 2 first and you have covered most of what happens.

Tier 1: get moving again

This tier answers the 20 million calls AAA takes for tows and batteries.

• A lithium jump pack. It works without a second car, which matters at 2 a.m. in an empty lot. Charge it twice a year or it's dead when you need it.

• A tire plug kit and a 12-volt compressor. A plug fixes a nail in the tread in about 10 minutes and gets you to a shop. It won't fix a sidewall.

• The jack, the lug wrench, and the wheel lock key. AAA reported missing wheel lock keys stopped technicians from changing 21,000 tires in one year.

• Traction help. Sand or cat litter and a folding shovel, both on Minnesota's list.

Tier 2: stay warm

• Wool, not cotton. Alaska's cold stress data sheet says to "Wear inner clothing which retains warmth even when it's wet, such as wool or polypropylene. Avoid cotton clothing." Down "loses almost all insulating value if it gets wet," and hypothermia happens above freezing.

• A real blanket. Wool or a sleeping bag, not a foil emergency sheet. The foil sheet is a supplement, not a plan.

• Hat, mittens, and boots. Most people dress for the walk from the car to the office.

• Hand warmers, which have a shelf life. Check the dates.

• A candle in a can, with limits. It takes the edge off a small space, but it's an open flame burning oxygen in a sealed car. It never replaces ventilation, or the blanket.

Tier 3: be seen and signal

Reflective triangles, a vest, a headlamp, spare batteries, and that red bandana. A whistle carries farther than a voice.

Tier 4: water and food the car won't ruin

Most lists quietly fail here, because they recommend food that can't survive a trunk. Skip anything that bursts when frozen, melts, or goes rancid in summer heat. What holds up: hard candy, nut butter packets, jerky, crackers, and a sealed jug of water you accept you'll replace. Utah State University Extension says stored water should be checked every 6 to 12 months and kept out of sunlight.

Tier 5: first aid, tools, and getting out

A first aid kit sized for cuts and road rash, work gloves, a multi-tool, duct tape, and a tow strap. Keep a seat belt cutter and window-breaking tool within reach while buckled in, not in the trunk. Know its limit: AAA tested six escape tools, and 4 broke tempered side glass while none broke laminated glass. About 1 in 3 2018 models had laminated side windows, so check the label in each window's bottom corner now.

Tier 6: documents and cash

Insurance card, registration, the roadside assistance number on paper, and 20 dollars in small bills.

Why is a car trunk the worst storage spot you own?

Because nothing else you own swings through that range. A parked sedan study summarized at Vehicle Heating Dynamics, published in Pediatrics in 2005, measured an average interior rise of about 19 degrees F in 10 minutes and 43 degrees in an hour, with cracked windows changing it by under 3 degrees. Then the same space drops below freezing in January.

• Water bottles freeze, expand, and split. A cracked bottle isn't water you have.

• Batteries and the jump pack. Heat shortens life, cold cuts output. AAA found electric vehicle range fell 41 percent at 20 degrees F with the heat running, the same chemistry working against your power bank.

• Canned food. University of Minnesota Extension says store cans at 50 to 70 degrees F, and that "Temperatures over 100 degrees Fahrenheit are harmful to canned foods." A summer trunk clears that easily.

• Medication, sunscreen, adhesives, and anything pressurized. Aerosols, sealant cans, and lighters don't belong in a hot trunk. Keep medication with you.

Our rule of thumb, not an agency figure: open the kit twice a year, at the daylight saving time changes. Swap the water, charge the jump pack, check the dates, move the blanket in or out.

What pre-trip checks matter more than the kit itself?

The ones that keep you from needing it. Three pay for themselves before winter.

1. Tire pressure and tread. NHTSA says check all tires including the spare at least monthly, when cold, and replace them at 2/32 of an inch of tread. NHTSA publishes no psi-per-degree figure; the familiar number, about 1 psi for every 10 degrees F the temperature drops, is a rule of thumb Wisconsin DOT has repeated. Treat it as a reason to check, not a measurement. Colorado DOT is stricter: its traction law requires one-eighth inch.

2. Washer fluid rated for cold. Summer fluid freezes in the lines and on the glass, and salt spray blinds you in seconds. Run the reservoir down before you switch.

3. The fuel rule. Michigan State Police say keep the tank at least half full to help prevent fuel line freeze-up. Colorado DOT says keep the top half of the tank full. That's also your heat budget: every hour you sit, the engine burns fuel 10 minutes at a time.

Phone power deserves a line. A car charger only works while the engine runs, and a cold power bank holds less, so keep it in the cabin and top it up when you rotate the kit. The rest of the seasonal list is in our guide to winterizing your home and car before a blizzard.

Frequently asked questions

What should be in a roadside emergency kit for winter?

Work in three tiers. To get moving again: a jump pack, a tire plug kit and 12-volt compressor, and the jack, lug wrench and wheel lock key. To stay warm: a wool blanket, hat, mittens and hand warmers. To be seen: reflective triangles, a vest and a headlamp. Then add water, shelf-stable snacks, first aid, a window-breaking tool, traction sand, and cash.

How long can you run your car for heat if you are stranded in snow?

The National Weather Service says to "Run the motor about 10 minutes each hour for heat" and to "open the window a little for fresh air" while it runs. Clear snow off the exhaust pipe first, because a blocked tailpipe pushes carbon monoxide into the cabin. Maine Emergency Management adds that one window should stay cracked anyway, since snow and ice can seal a vehicle shut.

Should you stay in your car or walk for help after a breakdown?

Stay with the vehicle in almost every case. Maine Emergency Management says to stay "unless you know exactly where you are, how far it is to possible help." The car is shelter, a windbreak and a large object rescuers can spot. Leave only if you can see the help you are walking to, or the car sits somewhere unsafe like a travel lane.

Are reflective triangles better than road flares?

For most drivers, yes. Triangles work for hours in rain, carry no fire risk, and do not expire in the trunk. Flares burn out, can ignite spilled fuel or dry grass, and are restricted in some states. Flares are brighter in fog and heavy snow, so add them only if you drive rural highways in those conditions.

How often should you rotate the supplies in a car emergency kit?

Twice a year is our rule of thumb, not an agency figure, and the daylight saving time changes are an easy trigger. A trunk swings from well over 100 degrees F in summer to below freezing in winter, which splits water bottles and drains batteries. Utah State University Extension says check stored water every 6 to 12 months.

The numbers, in one place

You never know, but you can always be ready.

Sources: AAA 2024 roadside service data, AAA on preventable breakdowns, AAA Slow Down Move Over, AAA vehicle escape tool testing, AAA cold weather EV range, NHTSA Traffic Safety Facts 2023, NHTSA tire safety, FHWA road weather management, CDC carbon monoxide, NWS winter weather safety, Maine Emergency Management, Minnesota Department of Public Safety, Colorado DOT, Michigan State Police, Alaska Department of Labor cold stress, University of Minnesota Extension, Utah State University Extension, Vehicle Heating Dynamics.