I didn’t think of that. That would require scientific testing. Good point!

Trams on average do not drive too fast. I would imagine that bees would easily be able to evade them or even be bumped out of the way.

I’d guess less than by not having any flowers at all. Where I live, most (non metro) trams drive pretty slow, like 30km/h in long straight parts, so unless they get between the wheels and the rails I doubt anything would really hurt the bees.