Every summer the same story runs, and every summer people assume it could not happen to them. It happens to careful, loving parents, most often on a day when the routine changed. Understanding the actual physics helps, because the numbers are worse than most people guess.
The numbers
A parked car acts like a greenhouse. Sunlight passes through the glass, heats the dashboard, seats and carpet, and that heat radiates back at a wavelength the glass will not let out. On an 80-degree day, the inside of a car can pass 100 degrees in about ten minutes and reach roughly 120 degrees within an hour. On a 95-degree day it can push past 140.
Roughly 80 percent of that temperature rise happens in the first half hour. There is no safe window of time, not even for a quick errand.
Why cracking a window does not work
Studies that compare cars with windows cracked to cars fully closed find only a few degrees of difference, nowhere near enough to matter. Shade helps more, and a light-colored car helps a little, but neither makes a parked car safe.
Children overheat faster than adults
A child's body heats up three to five times faster than an adult's. Heatstroke begins when core body temperature reaches about 104 degrees, and it becomes lethal around 107. A child strapped into a rear-facing seat cannot move out of direct sun, cannot open a door, and often cannot be seen from outside the car.
The habits that actually prevent it
- Put something you cannot leave without, your phone, wallet, badge or left shoe, in the back seat next to the child.
- Open the back door every single time you park, even when you know the seat is empty. Make it muscle memory. "Look before you lock."
- Ask your daycare or sitter to call you within ten minutes if your child does not arrive as expected.
- Keep cars locked in the driveway and keys out of reach. A significant share of hot car deaths involve children who climbed in on their own to play.
- When your routine changes, who is driving, which stop comes first, set a phone reminder. Routine changes are the common thread in most of these cases.
If you see a child alone in a car
Do not wait and hope the driver returns. Call 911 immediately. Get the child out if they appear to be in distress, and move them somewhere cool. Many states, Texas included, have laws that protect a person who acts in good faith to rescue a child from a hot vehicle.
Older adults and pets too
The same physics apply. Seniors, especially those on medications that affect temperature regulation, and pets of every size are at serious risk in a parked car.
Hope Drives puts working families back on the road
We give donated vehicles to people in Greater Houston who have the job and the housing, and are held back only by transportation. Applying is free.
