you need a serious traffic crisis

I would call the actual state a serious traffic crisis.

Average motorist speeds in cities hardly faster than a bicycle, gridlock whereever you look, commuter cars occupied by average 1.1 persons, almost half of driving time spent in search of parking space. And higher municipal deficits for sustaining individual motor traffic than those for mass transit.

This is Absurdistan.

I've not seen NYC when it's really bad-- midtown at noon?  Lincoln Tunnel on a Friday afternoon?

Our traffic was slower than it was when it was horse-drawn, in 1911.  About 9mph I think on average in the core of London.

I would say though that in the land of automobile and personal freedom, it has to get really bad (I sound like the Twilight Zone movie 'want to see something really scary? ;-) before something is done about it.

A big road repair programme might create the crisis eg shutting down the East or West Side Highways?