Dedicated lanes help with that. One way streets with timed lights help with that. Express Bus Routes work the same way, and do a good job of transforming paved roads into mock-mass transit systems. Not as efficient as trams, but still better than raw traffic.

But taking a lane out of circulation drives the car culture folks nuts. It's red meat for the talk radio screaming heads. And it tends to provoke an outsized political response from upper-middle class types who think they're too good to sit on the bus. Nevermind when a city reduces fairs to increase participation among poor residents. Then it's pillared as a welfare system, which we absolutely cannot have.

it’s crazy all the cities that just ripped their tram networks out

laughs in Henry Ford

Crazy, yes. It's an amazing coincidence how they got ripped out practically at once.