WASHINGTON (AP) After their 16-year-old daughter died in a car crash, David and Wendy Mills wondered whether she would be alive if federal rules on rear seat belt warnings had been issued on time.

Four years later, with no rule and traffic fatalities spiking, theyre still at a loss over the inaction.

The teenager was riding in the back seat of a car to a Halloween party in 2017 just a mile from her house in Spring, Texas, when she unfastened her seat belt to slide next to her friend and take a selfie. Moments later, the driver veered off the road and the car flipped, ejecting her.

Kailee died instantly. Her three friends who remained buckled walked away with minor scrapes.

A 2012 law had directed the National Highway Traffic Safety Administration , an agency of the Department of Transportation , to implement safety rules requiring car manufacturers to install a warning to drivers if an unbuckled passenger is sitting in a rear seat. The agency had three years to act.

But the regulation wasnt done when Kailee climbed into her friends car. Its one of more than a dozen car safety rules now years overdue, according to an analysis by The Associated Press.