Your car has a sensor that tells you when you've left the headlights on or the keys in the ignition. It probably has another reminding you and your passengers to buckle your seat belts, and still another that sounds when the door is ajar. Some cars even to tell you when the tires need inflating.
But so far, there's no standard equipment to tell you that you've left a child in the back seat.
"How many people died because their keys were left in the ignition, headlights left on?" asks Janette Fennell, who tracks hot-car deaths as president and founder of Kids and Cars. "They have the opportunity to eradicate this as a cause of injury and death to children for a relatively low cost. Why not do it?"
"The issue is not the technology; the issue is getting it to market," says Jan Null, a San Francisco-area meteorologist who also tracks child hot-car deaths.
Requiring such technology would translate into tens of millions a year in added costs to carmakers. But a spokesman for the Alliance of Automobile Manufacturers in Washington, D.C., insists cost is not the issue.
"Safety is the industry's top priority, particularly when it comes to children," says Wade Newton, whose group represents BMW, Daimler-Chrysler, Ford, General Motors, Mazda, Mitsubishi, Porsche, Toyota and Volkswagen.
Newton says no one has come up with a system that is immune to false alarms. He says the industry is constantly seeking safety improvements, but adds that all of these innovations "really work hand in hand with parental supervision."
There are products out there that could prevent most of these hyperthermia deaths. Among them:
— The Child Minder system replaces the car seat's harness clip with a "smart clip" synchronized to a key ring alarm. The unit is activated when the child is buckled in. As long as the child remains in the seat, an alarm will sound if the adult walks more than 10 feet from the automobile.
— NASA is on the verge of licensing its Child Presence Sensor, which replaces the clip with a weight-sensitive pad that fits under the car seat cushion. An alarm sounds 10 warning beeps if the driver moves too far away from the vehicle, and beeps continuously if the driver doesn't return within one minute. Engineers at the agency's Langley Research Center in Virginia developed the device after a colleague left his 9-month-old son in a hot car in May 2000.
— Volvo's flagship S80 sedan includes a Personal Car Communicator that can detect a heartbeat inside the vehicle and send a warning to the driver's wireless key fob. Volvo is marketing it as a safety option for women worried about back-seat attackers, not as a way to remind the driver of a child left behind.