The National Highway Traffic Safety Administration (NHTSA) is adjusting its stance on seat belts and for the first time is endorsing three-point seat belts on school buses.

Initially, the NHTSA had said that retrofitting the buses to include seat belts would be too costly, saying passengers were already adequately protected by the cushioned seat backs, according to WISH-TV. However, evidence has shown this "protective envelope" of close seats and cushioned backs isn't effective in every situation. Last month, a school bus without seat belts flipped over in Virginia, injuring 28.

The agency estimates four children die every year in large school bus crashes and believes seat belts would cut that number in half.

"It's this big void in our safety system," said NHTSA Administrator Mark Rosekind, according to CBS News.

Despite the change in stance, schools don't necessarily have to adjust their buses accordingly yet. So far, only six states - California, Texas, Florida, Louisiana, New York and New Jersey - require seat belts on school buses.

Rosekind was clear that he was not announcing a new rule. Rather, the administration will launch a series of projects aimed at improving data on seat belt safety, reported the Atlanta Journal-Constitution.

"Our goal is a three-point belt for every child on every bus," he said.

Provided that any city or state wants to install seat belts on its buses, such an endeavor won't come cheap. The NHTSA estimates retrofitting the buses would cost between $7,300 and $10,300 per bus.

However, Rosekind believes the results are worth the price. "Seat belts save lives, and that includes seat belts on school buses," he said.