An Iraq war vet appeared in court Saturday, facing charges of manslaughter and criminally negligent homicide in the hot car deaths of his 1-year-old twins. The number of similar tragedies is staggering. According to the National Safety Council, 818 children have died inside hot cars over the last 20 years.

Juan Rodriguez could not hide his grief as he was charged with the deaths of his infant son and daughter. Police say the 39-year-old veteran accidentally left the twins in a hot car and after his eight-hour shift as a social worker at a VA hospital in the Bronx, he found them dead in the backseat.

In a statement, Rodriguez's wife Marissa said "he is a good person and a great father."

On Friday, temperatures in New York City reached 88 degrees. Inside the car, it was even hotter.

"The temperatures can go up to 40 to 50 degrees higher than the outside temperature and you know I can tell you at 106 or 107, a baby will die," said Janette Fennell, president and founder of Kidsandcars.org.

Fennell warned even the most responsible parent can make this deadly mistake.

"This can and does happen to anyone, so look before you lock," she said.

Fennell also suggests placing your cellphone or your handbag on the backseat to remind you to open the back door. But Fennell said enhanced technology is the best way to prevent these tragedies.

That's similar to what CBS News found at a Kia dealership in New Jersey.

Although this type of technology already exists in some vehicles, safety advocates said the auto industry has been resistant to change. But Congress is now working on what's called the Hot Cars Act, which would standardize the technology in most new automobiles.