Every year, dozens of children die after being left alone inside parked cars, which trap heat like saunas and overwhelm the ability of young bodies to regulate temperature.
Earlier this month, eight kids died such tragically unthinkable deaths across the country in a span of just seven days -- an unprecedented spike that raised attention not just to the problem, but to potential solutions.
Some companies have developed devices that alert parents and caregivers to a tragedy waiting to happen. So far, however, all of those devices have flaws that make them unreliable and inconsistent, according to a new study.
For now, government officials and advocacy organizations are endorsing awareness campaigns that teach people about the dangers of leaving kids in cars and that offer strategies to help adults remember where their little ones are.
"Technology in its current form cannot serve as the stand-alone mechanism of preventing these events from happening," said University of Pennsylvania researcher Kristy Arbogast, director of engineering at the Center for Injury Research and Prevention at the Children's Hospital of Philadelphia.
"Manufacturers are going in the right direction, they're thinking about this in the right way," she added. "But the devices you can buy off the shelf right now just aren't reliable enough for something as important as child safety."
Since 1998, when record keeping began, 550 children have died in the United States from heat stroke in park cars. There are many more near misses than that, Carr said, pointing to Palm Beach County, Fla., where the fire department received 450 calls in one year about kids spotted alone inside parked cars.
Some years are worse than others.
In 2010, for example, 49 children died inside parked cars, a number that dipped to 33 in 2011. This year started out slowly, Carr said, with just three vehicular heat-stroke deaths in May, six in June and six in July. The unprecedented string of eight deaths during the first week of August brought the tally up to 23 deaths in 14 states for the year so far.
About 30 percent of the time, Carr said, these kinds of heat-stroke deaths happen after children escape the notice of their parents and climb into cars to play but can't get themselves out. Other cases happen when adults intentionally leave kids in cars, sometimes thinking they'll only be gone a few minutes and then getting caught up in errands or work that last longer than they realized.
More than half of the time, though, these tragedies happen to loving but stressed-out adults who are distracted by something, possibly sleep-deprived and often acting outside of their normal routines, Carr said. Maybe Mom is taking the kid to daycare on his way to the first day of a new job, for example, even though Dad normally does the drop-off. These accidents happen in equal numbers across race, class and education level.
In interviews that are heartbreaking to watch or read, parents who forget kids in cars often express disbelief that it happened to them.
Some companies and entrepreneurs have responded by creating products that aim to prevent drivers from leaving kids in cars.
There are a variety of stickers, bracelets and keychain trinkets available, for example, which are supposed to work as visual reminders. When you look at them, the idea is that you remember to check if your kid is still in the car.
Other devices slide underneath the part of a car seat where kids sit. Using weight sensors, they send a beep-inducing signal to a receiver, which fits on a keychain, but only if the receiver moves a certain distance from the device, and the seat is still loaded with the child's weight. The problem with these products, found Arbogast and colleagues in a recent study commissioned by the National Highway Traffic Safety Administration, is that they frequently malfunction.
The sensor might not sync correctly with the receiver, for example. Or batteries can run out without warning. The researchers found the same level of unreliability with a device that attaches to the chest-clip on a five-point harness and alerts a driver who moves too far away from a still-loaded clip.
"What we found was that all of these concepts are engineeringly sound, and they make sense, but they did not function reliably or consistently enough to serve as stand-alone measures," Abrogast said. "I'm a parent of two kids and as a parent, I would be frustrated with these things. You've got enough going on already."
Other concepts in the works but not yet on the market, she said, include sensors that could be integrated into cars or car seats and would detect motion, carbon dioxide or heat levels.
A company called Tomy International has announced plans to release a car seat with built-in sensors that can alert drivers about any number of dangerous situations, including a kid left inside a parked vehicle.
As researchers refine the technology, the NHTSA has started a new "Look Before You Lock" campaign, which reminds people to always check their cars when they get out and to never allow a child to remain unattended in a vehicle.
On an 80-degree day, according to a NHSTA press release, a car can reach deadly heat-levels in just 10 minutes, even if a window is cracked open a couple of inches. Young children overheat as much as five times faster than adults do.
To avoid unintentionally leaving kids in cars, Carr suggests that adults set up a system of reminders. Put something you'll need at your destination, like your cellphone or briefcase, in the back seat next to the baby. Place a stuffed animal next to you whenever there's a kid in the car. Call a friend or family member as soon as you drop your child off. And ask the daycare provider to call you immediately if your children don't show up at their normal time.
Experts also urge people to call 911 immediately if they ever see children inside a locked car.
"We have generally found that when parents or caretakers are involved, they're good people, particularly the ones that are accidental," Carr said. "We'd love to see the technology solution become available, but it's simply not there yet."