I have 42 clients (from a single rollover) that would quite like to argue otherwise...
But it's a rare occurrence...
...especially given the number of kids per day that are bused somewhere.
The problem with quoting statistics is that you stop considering the minority. How'd that work out for the world so far?
Only 13 people died as a result of GM's faulty ignition switch...yet there was a kind of a big deal made out of that...and Toyota's "unintended" acceleration? 1 person apparently died, and an even bigger deal was made of that. Statistics are inherently flawed.
If a bus were driving normally and was T-boned by a Mack truck, yeah, that's a "rare" occurrence that you cannot adequately plan for. My 42 clients were on a ski trip on a school bus, none of which are ever equipped with snow tires, and are known to be awful in the snow. That doesn't really matter though, since the accident was caused by the driver trying to take an off-ramp at a speed that was inappropriate for the conditions.
Summary: we should have higher standards for school bus drivers. Not necessarily saying that "only the elite can apply," but give better training to them.