Motorcycles in your bus lane

OK, so who has actually seen any studies that prove that there is a significant risk to cyclists/motorcyclists where motorcyclists are allowed to use bus lanes? By studies, I don't mean mutliple anecdotes - this is not scientific.

Or should the case against be based on discouraging m/cyclists from using the road?

isn't this the experimental period to collect data for those studies?

does anyone know of this type of arrangement being in place in any other countries?