Originally Posted by genec
While I fully agree with you that cyclists should not pass a right turning motorist on the right, and should in fact leave a BL as they approach an intersection, let's bear in mind that all too many motorists don't bother looking, or signaling their intent as they do their little moves on the road.
I know this too well, and it pisses me off, but the OP seems to indicate the motorist did communicate his desire to turn. Otherwise I'd expect the OP to complain about turning w/o a turn signal across his path.
Anyway, at least the car slowed down. That in itself is screaming "right turn" regardless of whether the turn signal was on or not. I'm not trying to imply it's ok to neglect to signal, but if you SEE anyway the driver is turning right, might as well pass on the left . In fact, it doesn't even matter why the driver is slowing down. If you're going to pass, do it on the left.
As you know, many people on this forum advocate moving to the centre of the lane at EVERY intersection to avoid right hooks. It can get tiresome and a lot of the time it's not necessary for various reasons, but there is definitely merit to that view, and in some conditions that probably is the absolute best way to ride.