NASHVILLE, Tenn. -- A rollover crash involving a school bus is one of those worst-case scenarios for school officials.
That's because, without seat belts, students have little to protect them.
Another reminder of that issue came Thursday when a Washington County school bus in East Tennessee ran off the road and flipped, resulting in 22 students being sent to the hospital.
School transportation officials have long argued that buses do not need seat belts because of something they call compartmentalization. That refers to those big, cushioned seats that are supposed to absorb the impact and protect children in a crash.
But, as our investigation discovered, it doesn't do a lot of good when the bus flips off the road.
Test video, from a company that makes seat belts for school buses, shows exactly what happens in the case of a rollover. Crash dummies are thrown around like clothes in a dryer.
And video from a real-life school bus crash shows just how violent a rollover crash can be.
"Rollovers are very common in accidents where children are hurt," said seat belt developer James Johnson.
"So while they may represent a small number of the accidents across the country, when they do happen, children can get hurt. That's when you'll find injuries and fatalities."
In fact, federal safety regulators have been warning for over a decade that school buses need to be made safer.
The National Transportation Safety Board wrote in 1999 that "current compartmentalization is incomplete in that it does not protect school bus passengers during lateral impacts with vehicles of large mass and in rollovers."
That's exactly the type of crash that has now traumatized another community.
The two big arguments against seat belts are that kids might abuse them, perhaps even use them as weapons. Transportation officials say it would be very expensive -- and these kind of crashes do not happen often enough to be worth the money.
So, in some ways, it's measuring kids' lives against the cost to taxpayers.