Modelling Local Demand and Locational Configuration in Floating Catchment Area Measures of Spatial Accessibility

Abstract

The modelling of catchment-based instead of local demand and optimal instead of sub-optimal character (i.e., locational configuration) of service delivery systems, commonly done in Floating Catchment Area (FCA) measures, generate spatial accessibility indices that might be misleading. The ability of recent FCA measures, three-step (3S) FCA, Modified (M) two-step (2S) FCA, and Balanced (B) FCA to capture local demand and locational configuration was examined in hypothetical systems and Rural Wards of Dodoma Urban District and found to be less appealing. The resulting 3SFCA, M2SFCA, and BFCA spatial accessibility indices inconsistently varied with the local demand or locational configuration. Thus, the study proposed a Modified (M) 3SFCA measure to effectively capture local demand and locational configuration. The proposed M3SFCA measure was implemented in hypothetical systems and Rural Wards of Dodoma Urban District and found to generate spatial accessibility indices that logically varied with local demand and locational configuration. The service users (or households) with low local demand or closer to service providers (or water points) are characterized by higher spatial accessibility indices and vice versa. This characterization of spatial accessibility indices is more realistic and essential for effective monitoring of progress made on the global and national development goals.