Aug. 22, 2010, was the worst day of Jenny Stanley's life, and she wants to make sure other families don't experience one like it.

That Sunday was the day her 6-year-old daughter, Sydney, died in a hot vehicle. Stanley believes the little girl crawled into the family's SUV outside their home in Alpharetta, Ga., to search for a craft from church and died of vehicular heatstroke.

Tragically, the family's loss has been followed by hundreds of others. The previous two years have seen 54 and 53 such gruesome deaths, respectively, in the United States, the most children lost in such a span. The number is expected to be even higher this year, with more vehicles parked at home because of COVID-19 restrictions, often unlocked, rather than driven to, say, an office.

There's also the problem of harried parents — their stress level heightened by the demands of the pandemic — unintentionally leaving their children in the back seat of the car.

After she lost her daughter, Stanley became an advocate, working with the nonprofit group KidsandCars.org.

"I wanted to be sure that another child didn't pass away to heatstroke. I wanted to be sure that another family didn't have to go through this. So now my mission is to have every car installed with a child detection device," Stanley said.

Last year, automakers pledged that systems reminding drivers to check the rear seat before exiting the vehicle would be standard equipment on almost all passenger vehicles sold in the United States by the 2025 model year. But safety advocates have blasted the move as inadequate. They want systems that detect the presence of children, not just remind someone to check the back seat, and can alert the driver after he or she has left the vehicle.

They believe that such technology already exists, pointing to a General Motors pledge in 2001 to roll out sensor technology by 2004 "so sophisticated that it can detect motion as subtle as the breathing of an infant sleeping in a rear-facing child safety seat."

When asked about the issue last year, GM, which has defended its focus on safety, explained that "systems that accurately and reliably detect children in vehicles have not been widely deployed across the industry due to continued challenges with the accuracy of sensing systems given the broad number of vehicle/seating configurations and the varied positions of children in vehicles."

A universal problem

The families that have lost children in hot vehicles range across racial, educational and socioeconomic backgrounds. And while the occasional alarming news report surfaces about parents deciding to leave children in the car while they run an errand, the vast majority of the incidents are inadvertent, experts say.

That describes what Janette Fennell, founder of KidsandCars.org, has seen.

"All it takes is a simple change in routine when parents are totally sleep-deprived and stressed," she said. "Everyone who has had children knows that that first year of a child's life we're operating in a bit of a fog, and because that is simply a fact, I know as a country we can do more to protect our littlest, precious babies."

There are laws prohibiting leaving children unattended in cars, and some parents have been prosecuted. But that doesn't serve as a deterrent when the act is unintentional.

Fennell called the cost of adding child detection technology inconsequential to the price of a new vehicle, ranging from an extra $10 to $40. Her organization also has noted that because of the length of time it takes the vehicle fleet to turn over — the average car in the United States is 12 years old — it would be years before new technology would be installed in a majority of vehicles.

In the meantime, proponents are making an educational push. One suggestion is to put something that you're certain not to leave the car without, such as a purse or wallet, in the back seat.

"Make it a habit to check your entire vehicle — front and back — before locking the door and walking away. Train yourself to park, look, lock, or always ask yourself, 'Where's baby?' " the National Highway Traffic Safety Administration suggests.

Heatstroke can begin when the body temperature reaches 104 degrees. It also can happen quickly. A vehicle's interior temperature can rise almost 20 degrees in 10 minutes, according to experts. A cloudy day is not a defense against vehicular heatstroke, they add.