This sounds awesome, but I'm guessing can only work if there are few buses? (I live in London and can't imaging such an arrangement being even remotely workable around here.)
The trams in Croydon work this way. There's an induction loop on the tramway which detects an approaching tram, and tells the traffic lights to change to allow the tram to cross the road/junction.
https://www.whatdotheyknow.com/request/tramlink_tram_priorit...