Functional Cities, Administrative Boundaries: Metropolitan Infrastructure and the Cost of Fragmentation

Abstract

Cities are functional systems defined by commuting, water catchments and waste flows, while the authorities that plan and fund their infrastructure are defined by administrative lines drawn for other purposes. This study examines the consequences of that divergence and what follows for infrastructure design. The method is a structured review of research published between 2017 and 2024 combined with a synthesis of published quantities on urban expansion, fragmentation and cooperation. Three findings follow. The functional city is now the majority setting: a global delineation identifies 8,790 functional urban areas containing roughly 3.9 billion people, some 53 per cent of the world population, and across 363 million-plus cities urban land expanded at 1.08 per cent annually between 1970 and 2014 while the influence of economic growth on that expansion rose markedly after 2000. Growth has moved outward: in one Indonesian conurbation corridor urban land rose from 10.26 to 22.27 per cent of area between 2000 and 2020, while in another metropolitan region the primary city was relatively stagnant and development intensified in secondary cities. And fragmentation is costly, with fragmented metropolitan governance associated with lower productivity by an amount its authors describe as at least as important as the benefit of city size. The study argues that the operative design question is not whether jurisdictions should cooperate but which functions should be delegated upward, since the cooperation evidence indicates savings arise specifically where delegation to a higher tier occurs.