Each year, dozens of children and untold numbers of pets left in parked vehicles die from hyperthermia, which occurs when the body absorbs more heat than it can handle. Hyperthermia can occur even on a mild day with temperatures 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. Leaving the windows slightly open does not significantly decrease the heating rate. The younger the child the more severe the effects because their bodies have not developed the ability to efficiently regulate its internal temperature. Get free downloadable flyers, banners, fact sheets, and more on infant and toddler car safety.

The sun's shortwave radiation (yellow in figure below) heats objects that it strikes.  For example, a dark dashboard or seat can easily reach temperatures in the range of 180 to over 200°F. These objects (e.g., dashboard, steering wheel, child seat) heat the adjacent air by conduction and convection and also give off longwave radiation (red in figure below) which is very efficient at warming the air trapped inside a vehicle. Shown below are time lapse photos of thermometer readings in a car over a period of less than an hour. As the animation shows, in just over 2 minutes the car went from a safe temperature to an unsafe temperature of 94.3°F. This demonstration shows just how quickly a vehicle can become a death trap for a child.

Objects Heated by the Sun Warm Vehicle's Air


CLICK HERE FOR ANIMATION (700K)
( Hi-Res ~ 2.5 mb.WMV file)
Individual Frames:
0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min 
Animation Courtesy of General Motors and San Francisco State University. Use of this animation does not imply NWS endorsement of services provided by General Motors and San Francisco State University. 

Hyperthermia deaths aren't confined to summer months. They also happen during the spring and fall. Below are just a few of MANY tragedies.

• North Augusta, SC, April: A mother left her a 15-month-old son in a car. He was in a car for 9 hours while his mom went to work. She is now serving a 20-year prison sentence.
• Honolulu, HI, March: A 3-year-old girl died when the father left her in a child seat for 1.5 hours while he visited friends in a Waikiki apartment building. The outside temperature was only 81 degrees.
• Greenville, TX, December: A 6-month-old boy died after being left in a car for more than 2 hours by his mother. She was charged with murder. The temperature rose to 81 degrees on that day.

Adults also are susceptible to hyperthermia in vehicles. On July 12, 2001, a man died of heat stroke after falling asleep in his car with the windows rolled up in the parking lot of a supermarket in Hinds County, MS.