In message , at 10:05:25 on Fri, 4 Aug
2017, Someone Somewhere 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 with
double decker buses/coaches than it has from trams (once).
Neil
Indeed - a quick search for coach overturned on google returns a
considerable number of examples.

All the ones I found in a quick search were either because they'd
swerved to avoid another vehicle, or they'd left the road and typically
toppled into a ditch. Neither of these is very likely to be echoed on a
tramway.
--
Roland Perry