Measuring access to primary health care using two-step floating catchment areas and a public/private multi-modal transport model

Floating catchment area (FCA) models are widely promoted as a technique to measure potential accessibility in a range of health applications. The period since their initial formulation in the early 2000s has seen a number of enhancements to the methodologies originally proposed to measure accessibility. Encouraged by the growing availability of sophisticated road network data, and a realisation of the inherent limitations in the use of straight line distances in such models, there has been an increasing adoption of network distances within such models. However, the majority of studies using FCA models are still predicated on the assumption that people access health care facilities using only private means of transport. This study describes how public transport availability and frequency can be incorporated into FCA models to provide a more realistic appraisal of accessibility for those population groups most likely to be reliant on public means of transport to access health care services. The potential advantages of this approach and its policy implications are illustrated with reference to a case study of access to primary health care facilities within South Wales, UK.