Bus-only traffic lanes (or bus/streetcar shared lanes) are also easy to “add” by repainting existing shared use lanes. Where I live (Portland OR) the city converted a few of our major streets to work like this, and it’s noticeably improved the bus experience during heavy traffic.
Some people just aren’t in a position to deal with riding around in 100F+ heat like we’ve had this last week, myself included. Having quick bus access (and busses with AC!) has been so great!