August 4, 2010
Rae Zimmerman resources and services for transportation, energy, communications, water supply, and wastewater collection and treatment. In large part, the increasing spread of population settlements at the periphery of cities and the increasing density and vertical integration of urban cores have increased reliance upon the connectivity that these networks provide. These infrastructure networks are, in turn, dependent upon one another, both functionally and spatially, in very complex ways, and that interdependence is increased as new capacity-enhancing infrastructure technologies are developed. The extent of these dependencies appears to be escalating, and that results in interactions among the systems and produces effects upon environments that are difficult to predict. Integrating these services can improve the performance of the infrastructures, lower investment costs, and improve urban lifestyles. However, although some spatial and functional coordination of these networks has occurred, the rapid growth in their deployment, advances in network technology, and changes in the distribution of the populations the networks serve, continue to create disruptions in the infrastructure systems.