In message , at 09:44:03 on Fri, 4 Aug
2017, Neil Williams remarked:

There's more to do when driving a bus, therefore drivers don't fall
asleep as often. There are also very few instances of buses toppling
over because they took a bend too fast.

It certainly does happen. Indeed, it's happened a lot more

There's a lot more buses and coaches

with double decker buses/coaches than

Do you have a cite for one where it was speed, rather than a side effect
of the bus/coach having also left the road first?

it has from trams (once).

Sixty casualties. That's a whole bus-load in one go.
--
Roland Perry