Some cities simply can't do this, such as Los Angeles, Dallas, and Atlanta. It's not in their DNA. Things are simply too far apart and the infrastructure couldn't hold it. Other cities are moving toward "no cars" by simply allowing gridlock to make driving a car worthless. I visit NYC very often, and we used to take cabs all the time. Now, we never do, unless we have so much luggage we can't manage - it's a nightmare…
One thing I'll add, the "allowing gridlock" is like "allowing water to fill a container". It more or less is what an incompressible fluid does which is essentially what traffic is. That's why road widenings don't neccessarily decrease congestion, when you take into the non-linear effects (induced demand).
Oh no, more people can get to their destination by their preferred mode of transportation! How horrible!