The past half-century has seen explosive growth in the world population, with society's numbers burgeoning from 2.5 billion in 1950, to 7.3 billion in 2015. During this same period, the population of the United States followed suit, more than doubling, from 157 million to 325 million.
This rapid population increase has strained natural resources and infrastructure systems in myriad ways, at multiple scales – but disproportionately so for urban areas, where more than 80% of the U.S. population now resides. The population density challenges range from ensuring the safety of tens of millions of citizens, to managing highly dynamic energy, water, and transportation demands, to mitigating pollution impacts.
The challenges are so complex that they have outstripped humans' unaided intellectual capacity to address them. This important observation is a fundamental tenet of the Smart City vision, and a focal point for researchers working in the Infrastructure Systems area.