this data shows that nearly all of the worlds large urban areas have extensive suburbs of much lower density outside the central cores that are characterized by higher densities in most cases some postautomobile urban areas have virtually no urban cores at allxxithese findings are backed by a joint study by unhabitat new york university and the lincoln institute of land policy on a representative sample of cities across the globe which established that the average rate of the physical expansion of cities is about oneandahalf times that of their population growth by measuring the rate at which cities consume land compared to their rate of population growth city authorities and decision makers can project demand for public goods and services identify new areas of growth and proactively influence sustainable urban development