City population dynamics and fractal transport networks

We consider the dynamics between population and spatial distribution networks for the 200 largest urban agglomerations. Population dynamics are considered from 1950 to 2010 and distribution networks are analyzed in terms of vehicular transportation infrastructure. We observe that the growth of large urban agglomerations, in terms of population density, has slowed down in the second half of the twentieth century as their transportation infrastructure has become more complex. Computing inequality indices furthermore reveals that the resulting urban system is less concentrated than it used to be, with a larger share of the urban population distributed in more numerous, relatively smaller urban agglomerations. We analyze transportation infrastructure in terms of fractal dimension and found that developed continents have higher fractal dimensions and lower populations than non-developed ones. We speculate this is due to varying road widths existent in some areas and absent in others. More complex networks in effect extend the range of cities and offer increased cost to benet utility. Better understanding of universal principles associated with such networks affords an opportunity to assess our control of urban agglomerations and their relation to the larger ecosystem they inhabit. Further analysis is necessary to combine the above approaches with additional data and to develop a more comprehensive metric for assessing and addressing the long term ecologic, economic and social implications of urban development.