Time to put seat belts and rear facing seats in school bus.
There are a lot of practical reasons why seatbelts on public school buses aren't the best idea. Kids aren't going to put them on correctly, for one. For another, imagine how long a bus route would take, if kids are having to fasten and unfasten them. Passive safety devices such as extra padding are probably better. Seatbelts wouldn't have saved those killed in this crash, either. They'd have been crushed by that tree while strapped in their seats.
Rear facing seats would help with frontal impacts but not rollovers. I remember riding in the back of station wagons with rear facing seats as a kid. Better bring some Dramamine. Riding backwards seems cool but triggers motion sickness in my experience.