Originally Posted by John Forester

This is partly correct, partly fallacious, hence rather mendacious. Vehicular cycling was the dominant mode from the invention of the bicycle, and hence was the condition in which the enormous development of cycling occurred. Your claim pertains only to after the introduction of mass motoring, when cycling of all kinds declined.

Your claim regarding vehicular cycling in the USA is false, because the predominant, official, socially desired mode of cycling in the USA has been cyclist-inferiority cycling, now enforced by bikeways. The decline of cycling in the USA has nothing to do with vehicular cycling; the causes are much more associated with general social, demographic, and economic conditions.

Great Britain's experience fits your example, but the UK was very different from the rest of Europe over all these decades, being, as far as transportation is concerned, more like the USA than the central European nations. In 1952, two years after British petrol rationing ended, bicycle traffic constituted 25% of the vehicle miles on British roads, and it has declined since.

Your claim that "Where cycling facilities have been installed, and motor vehicle use has been discouraged, cycling for transportation has soared to be as much as 25% of all trips" is false, both in fact and in reasoning. It would be more accurate to state that in those nations in which there had been the greatest bicycle modal share, the decline has been less, with some areas having a modal share as high as 25%. These areas were developed as walking cities in which walking is convenient, although bicycling is faster, and motoring is inconvenient, and the authorities have maintained those characteristics as much as possible. Only one of the means has been the provision of bicycling facilities, and there is no means of evaluating the effect of the various means and conditions.