I think bus lanes are great: the faster you make buses the more people switch from cars, which means the more frequently you can run the buses, which means even more people switch from cars. But when there's traffic drivers are often tempted to sneak over. The chances of getting a ticket are pretty low, other people are doing it, and then when a bus does come through there are cars in its way. Which loses much of the benefit of setting aside a lane for buses.
Some places (ex: NYC) handle this by putting automated traffic enforcement cameras on buses, and this was proposed for MA with Bill H.2494. [1] I think this is a good idea, but I'd like to see this go even further: put cameras on all the buses and then don't enforce it otherwise.
The idea is, in cases where you don't delay a bus then by using the lane you're making traffic a bit better for everyone else. You might be about to make a right turn, you can see that there's no bus coming, and you're going to be out of the way before any bus you don't see yet would be near. Or you're using a GPS for navigation which also knows the real-time bus locations, and it tells you you're safe to use the lane. By limiting enforcement to only cases when someone actually does delay a bus, it ought to be possible to both keep the lane clear for buses with less waste.
Since some people would still be scrupulous and want to stay out of the "buses only" lane regardless, I'd also want to see us change the law from "no cars" to "no cars slowing down the bus".
[1] The bill history ends with "1/3/2023, House: No further action
taken". I'm not sure exactly but I think maybe because it was a bill
in the 192nd congress and we're now on the 193rd this means it's dead?
I am a fan of combined bus + bike + right turn lanes. But I say this as a bicyclist and motorist, not a bus user.
The benefit to bicyclists is that we get a real full-width lane to bike in the center of, without much traffic. This provides generous distance from debris on the right, and from traffic in the lane to the left, as well as optimal sight lines to and from traffic at intersections. And bus drivers are more courteous, attentive, and law-abiding than the average motorist. I have never had a problem using the full lane ahead of a bus.
However, after reading your post I have a new appreciation for how much that could slow down buses, depending on how common bicyclists are. Of course buses can change lanes to pass just like everyone else, and buses in a bus lane have to change lanes to make left turns anyway, but in heavy traffic it would reduce some of the benefit to buses of having a special bus lane.