A cumulative opportunities approach to facility location

This study introduces a new facility location model to optimise the cumulative opportunity measure (COM), an accessibility metric frequently utilised by urban planners, but which has not to our knowledge previously been used in facility location optimisation. COM counts the (distance-weighted) number of service opportunities available within some predefined threshold distance of a demand point. We account for service equity considerations by use of a constraint bounding the Gini coefficient value for cumulative opportunities across demand points. We conduct a numerical study benchmarking the proposed model against three common facility location models (p−median, p−centre and maximal covering). Results demonstrate that COM-maximising solutions can differ significantly from those obtained by these classic models. We illustrate our approach using a case study applying the proposed model to community health centres in New York City. By utilising a metric that is well-known in the planning community, the proposed modelling approach could help to increase policy makers’ willingness to rely on optimisation modelling to inform their decision making.