Summer is road trip season, and it is also the season when a car can become dangerous in a matter of minutes.
A quick stop for gas, a restroom break or a souvenir shop can turn serious if a child, a pet or a sleeping passenger is left behind in a parked vehicle.
Heat also wears on everyone in the car during long days of driving.
This guide covers how a parked car heats up, the habits that keep children and pets safe at every stop, and how to recognize heat illness before it becomes an emergency.
How fast a parked car heats up
Most people underestimate how hot the inside of a car gets.
According to the National Weather Service, even on mild days in the 70s, studies have shown that the temperature inside a parked vehicle can rapidly rise to a dangerous level for children, pets and even adults.
The sun shines through the windows and heats every surface inside.
The NWS notes that a dark dashboard or car seat can quickly reach temperatures in the range of 180°F to over 200°F, and those surfaces then heat the air trapped in the cabin.
Cracking the windows is not a solution.
The NWS states that leaving the windows slightly open does not significantly decrease the heating rate.
Why children are at special risk
Children are not just small adults when it comes to heat.
The NWS points out that newborns, infants and young children are particularly vulnerable to heat-related illness, because their bodies are less able to adapt to heat and they warm at a faster rate than adults.
The NWS also warns that each year dozens of children and untold numbers of pets left in parked vehicles die from hyperthermia, which means the body has overheated. Many of these tragedies happen to loving, careful families during a change in routine, and a road trip is exactly that kind of change.
The rules for every stop
The NWS lists a short set of habits that prevent hot car deaths.
They are simple enough to follow at every gas station and rest area on the trip.
- Never leave a child alone in the vehicle. Not even with the windows down, and not even for just a minute.
- Check the back seat every time. Always make sure children have left the car when you reach your destination, and do not leave sleeping infants in the car.
- Lock the car. Always lock the doors and trunk, even at home, and keep keys out of children's reach.
- Teach kids that cars are not play spaces. Children can trap themselves in a hot vehicle while playing in or around it.
- Touch the car seat first. Before buckling a child in, touch the safety seat and the belt buckle to make sure they are not too hot.
On a long drive with several adults, agree on who is responsible for each child at every stop.
Saying it out loud prevents the dangerous assumption that someone else has the baby.
Pets need the same protection
The same physics applies to dogs and cats.
A pet waiting in a parked car while you grab lunch is exposed to the same rapid heating, with no way to cool down or escape.
Plan stops around your pet. Choose pet-friendly restaurants with outdoor seating, use drive-throughs, or travel with another adult who can stay with the animal in the shade or in an air-conditioned building.
Carry water and a bowl for your pet, and give them a chance to drink at every break.
Keep everyone hydrated
A long day in a warm car is dehydrating even when the air conditioning is running.
The NWS recommends drinking plenty of water and other non-alcoholic, decaffeinated fluids, even if you do not feel thirsty.
Pack a cooler with water and easy snacks. The NWS suggests light, cool, easy-to-digest foods such as fruit or salads, and reminds travelers to keep packed food in a cooler or with an ice pack, because meats and dairy products can spoil quickly in hot weather.
Dress for the heat, too.
Lightweight, loose-fitting, light-colored clothing reflects heat and sunlight, which helps a lot when you step out of the car into a hot parking lot.
Plan the day around the heat
The NWS advises reducing or rescheduling strenuous activities to the coolest time of the day.
On a road trip, that often means hiking, sightseeing and long walks in the morning or evening, with driving in the hottest hours when everyone is inside an air-conditioned car.
Check the forecast for every region on your route, not just your destination.
Extreme heat also affects the road itself: the NWS notes that high heat can deteriorate and buckle pavement.
Before leaving, make sure the air conditioning works well.
A weak A/C is an inconvenience at home and a real problem on a desert highway with young children in the back seat.
Know the signs of heat illness
Heat illness can sneak up on travelers who spend the day moving between a cool car and hot outdoor stops.
The NWS heat illness page, which draws on CDC guidance, describes the warning signs.
- Heat cramps: painful muscle cramps and spasms, usually in the legs and abdomen, with heavy sweating. They may be the first sign of heat illness.
- Heat exhaustion: heavy sweating, weakness or tiredness, cool, pale, clammy skin, a fast and weak pulse, dizziness, nausea or vomiting, headache or fainting.
- Heat stroke: a throbbing headache, confusion, slurred speech, a body temperature above 103°F, hot, red, dry or damp skin, a rapid and strong pulse, or loss of consciousness.
For heat exhaustion, the NWS advises moving the person to a cooler place, preferably an air-conditioned room, loosening clothing, applying cool, wet cloths and offering sips of water.
Seek medical attention right away if the person vomits or the symptoms get worse or last longer than an hour.
Heat stroke is a severe medical emergency.
Call 911 or get the person to a hospital immediately, move them somewhere cooler and lower their body temperature with cool cloths while you wait.
The NWS says not to give fluids to someone with heat stroke.
A hot-weather road trip checklist
- Test the air conditioning before you leave.
- Pack a cooler with water, light snacks and ice packs.
- Bring water and a bowl for pets.
- Agree on who watches each child at every stop.
- Look in the back seat every time you lock the car.
- Touch car seats and buckles before buckling children in.
- Schedule outdoor activities for the cooler hours.
The bottom line
A parked car in summer heats up far faster than most people expect, and cracked windows do not change that.
Never leave a child or a pet inside, even for a minute, and build the habit of checking the back seat at every stop.
Keep everyone hydrated, plan outdoor time for the cooler hours and know the signs of heat illness.
With those habits in place, the heat becomes part of the scenery instead of a danger.
Sources and Further Reading
- National Weather Service: During a Heat Wave — supports the parked-vehicle heating facts, the dashboard temperature range, the cracked-window finding, the child and pet safety tips, the hydration, food and clothing advice and the effect of heat on pavement.
- National Weather Service: Heat Cramps, Exhaustion, Stroke — supports the symptoms and first aid steps for heat cramps, heat exhaustion and heat stroke.