Some Thoughts on Squares & Transportation

I was idly thinking about how transportation (be it mass transit, roads or highways) corresponds to population centers (more specifically squares and neighborhood centers) and I came to the realization that it is your classic chicken or the egg quandary. In order for people to travel to and from a location they need a means of transport, but in order for their to be a means of transport their needs to be a location. Which leads to the question why do we build new or better transportation? Is it because the population demands it or is it in anticipation of the coming population? I would say it's probably a mixture of both with their being extremes on both ends. Governments build bridges to nowhere and subsidize rural airports but they also are forced to add lanes to highways and expand train/plane capacity. An interesting thought experiment either way.