Activity spaces as indicators of food deserts

Abstract

The theory of activity spaces (AS) originated from biological research conducted on habitat use, territorial behaviour, and mammalian home range studies dating back to the 1950-1960s. Since then, it has been applied in various fields such as the analysis of crime incident locations, accessibility to healthcare services, the impact of transit-oriented developments, or to study food deserts.

AS refer to the areas that individuals interact with in their surrounding environment and capture travel demand, supply, time limitations, and institutional constraints. AS are geospatial, statistical measures that describe the spatial use (realised AS) or spatial perception and awareness of travellers at the individual or aggregate level.

As a result of significant improvements in the quality of transport services, such as increased frequency or speed, there is a greater potential to reach further destinations. This is often reflected in larger activity spaces or time savings embedded in stationary activity times. Additionally, AS adjust dynamically due to changes in the built environment and transport services.

This paper focuses on food deserts in Perth, Western Australia and explores various formulations for measuring the potential to access opportunities by combining spatial and temporal information, such as frequency and duration. Foodscapes refer to the food environment in an area, including the availability, accessibility, and affordability of food. We distinguish between food deserts, areas with limited access to affordable and nutritious food; food swamps, areas where unhealthy food options are prevalent; and food oases, areas with an abundance of healthy food options. The analysis uses anonymised mobile phone location data to build AS, which are then compared to clusters of food environments with varying levels of richness, abundance, and diversity, as well as with socio-economic indicators. The findings suggest that individuals from lower socio-economic backgrounds have poorer AS due to limited access to food outlets near their homes (food deserts). On the other hand, those living in affluent areas or travelling further (larger AS) had greater access to food outlets and healthier food options. Working in activity centres, further from home but with access to food en route, was associated with better access to high-quality food (food oases).

Additionally, the study identifies the Perth CBD and suburban activity centres as important locations with high food abundance and diversity, as well as with socio-economic indicators.