Optimal Municipal Size, Population Density and Urban Growth: The Unexplored Nexus

This study contributes to identification of optimal municipal size by investigating the latent relationship between urban growth, population density and municipal area in an European metropolitan region (Athens, Greece) expanding between 1951 and 2011. Transformations in municipal boundaries or creation/suppression of new administrative units were hypothesized to reflect a progressive adjustment toward a more balanced distribution of population over space. In rapidly expanding metropolitan regions, municipal size is an important variable outlining amount and spatial concentration of services and infrastructures, being functionally related with both population density and land availability to building. Based on these premises, a quantitative analysis of the relationship between population density and municipal area provides basic knowledge to assess optimal municipal size, identifying policy and planning adjustments to a more balanced spatial distribution of population and land among local government units. Descriptive statistics, correlation analysis and linear regressions were used to evaluate such relationship over time. Average municipal size in the study area decreased moderately over time with a slight increase in spatial heterogeneity; conversely, average population density per municipality increased more rapidly with an evident reduction in spatial heterogeneity. Linearity and significance of the relationship between municipal size and population density increased consistently over time, reaching the highest values in 2011. Results of this study suggest that urban concentration across metropolitan areas has progressively adjusted to municipal size, with a more balanced distribution of resident population. These conditions represent a base for informed analysis of the spatial structure of local administrative units.