First, these cities should be fixed by removing the traffic magnets. It's far past the point where we used the old obsolete ideology of trying to supply as much traffic capacity as possible.

But anyway, your statement is actually not true anywhere in the US except NYC. Even in Chicago, removing ALL the local transit and switching to 6-seater minivans will eliminate all the traffic issues.

Car traffic magnets like highways inside urban cores? Or people traffic magnets like office buildings, colleges, sports stadiums, performing arts venues, shopping malls?

6-seater self-driving municipal minivans would be fantastic, too. (I would still call that a "bus", but I don't care what we call it.)