This is far more than a cycling issue. Rather, it concerns the conditions under which it is possible to have a high-density urban center with limited motoring, in a world in which motoring is generally available. Such a center can exist only if its attractions are extremely strong; without such extremely strong attractions people just won't go there, which means that, without people, it cannot be a high-density urban center. Of course, Los Angeles, as an urban area, is high density, but, notice, there is not really a high-density urban center to LA. Those that exist have been from before the automotive era, but have, still, attracted so much motoring as to become very congested.

Suppose that motoring in the urban area would be limited to some small fraction of what it had been. Say by some rationing system, by price or by otherwise. Would sufficient mass transit spring up to serve the center's needs? Would park-and-ride facilities to service that mass transit spring up sufficient to serve the center's needs? Would sufficient apartment buildings spring up to house all those who no longer would come into the center from outside? Or, in the face of these difficulties, would the urban center decline because economic activity moved elsewhere? I repeat, the attraction of doing business in such a center has to be extremely strong to enable it to exist, and the size of its economic activity depends on the strength of that attraction.