Haven't heard of any frequent accidents involving the tail of
the bendy striking a person/vehicle while negotiating the road. At
least so far.
But there are many complains from other road users that the tips of
the back trailers almost hit them, especially when the road is wet.
But mounting kerbs seems pretty common.
It is generally accepted that articulated buses are more
suitable for shorter services with a constant flow of passengers
boarding and alighting. This is because articulated buses
promote faster dwell times at stops due to the ease of access.
As stated by others above, articulated buses have several major
advantages: they are the same height as a single-deck rigid bus
meaning that they can travel (almost) anywhere that a normal
single-deck rigid bus can and they are generally safer for
passengers.
Articulated buses also tend to share a high proportion of parts
with the corresponding single-deck rigid bus, so the extra
servicing complexity is minimal.
Double deckers are suitable for longer limited stop and express
services where the frequency of stops (and therefore movement of
passengers on and off the bus) is less. A crowded double
decker bus is likely to take much longer to unload than a crowded
articulated bus, and passengers need to negotiate a staircase in
order to disembark from the upper deck. Additionally, double
decker buses are much taller and much consideration needs to be
taken for the route that they are used on. Double decker
buses place more weight per axle onto the road and are therefore
more damaging to the road network, but on the other hand, they take
up less depot space and road space.
Actually bendy buses are the most harzardous model among the 3
types of buses used in Singapore.
Bendy buses have the highest accident rates here, followed by
single deckers with double deckers (10.6m and 12m versions) the
safest on the roads. This is according to someone who have friends
working in LTA.
Bendy buses have longer length and thus higher risks of meeting
an accident with other vehicles. Moreover, bendy buses joints are
controlled by an electronic turntable. No matter what, electronics
will not always be failproof and is worse if not maintained
properly. There will be instances that it might malfunction and
cause slight sways for the trailer. Worn out tires, wet roads, plus
inbalanced loads at either trailers would cause potential hazards
of swaying trailers. However all these can be prevented with costly
maintanance but this will just increase operating costs for such
kind of buses as compared to a double or single decker.
And more, bendy buses accounts the highest number of burnt bus
incidents started by themselves in Singapore.
Thus bendy buses are more dangerous as it seems in
theory.
One incident today had further made me believed that bendy buses
are not suitable here, especially in big numbers.
A bendy broke down this morning at 811/854 berth Yishun
interchange. The whole bus almost blocked the passage way, leaving
a small gap which other buses still can go through slowly. Other
buses behind got a bit delayed with the slow traffic. One
replacement bus, a Dennis Lance have to move in front of the broken
down bendy to carry those stranded passengers. And just bad timing,
a 854 bendy had to fetch its passengers as well and so have to park
behind the broken down bendy but BC realised he parked too near
behind so had to reverse a bit, then BC honked at the queue to
board. The first few passengers can't see the bus number at first
as it was too far off the berth and thought cannot board. Then
these passengers also have to walk a long way bypass the broken
down bendy to board the 854 bus.
The length of the 854 bendy again blocked the 171/812 berth,
which cause another 812 bus had to delay in stopping at the berth.
One single decker along the slow traffic honked at the slow
traffic, presuming that the BC had already been late. 
Just look at the choas caused by a broken down empty 17.5m bus,
and it slows down other buses and passengers and the operations of
the bus intercahnge. If the bus is a 12m, would it be so chaotic???
And Yishun interchange is bigger than some of the newer ones. The
future Yishun interchange might be smaller and if this happens, it
will be much worse. 