(Georgia Institute of Technology, 2023-07-28)
Moss, David
“Food deserts” are areas of an urban environment that are judged to have no
accessibility to a nearby grocery store. Traditionally, this accessibility is based on a simple
measure of Euclidean distance, i.e. a circle of a given radius drawn around the nearest grocery
store, thus ignoring the actual road network used to travel to said store. This paper proposes a
methodology for constructing isochrones, polygons which both incorporate the actual distance
travelled to reach a given grocery store, as well as the time it takes to traverse said distance via
a variety of different modes. Doing so dramatically reduces the estimated coverage area of a
given grocery store, and helps visualize the inequities inherent in using distance-based measures
of accessibility without accounting for the mode taken to travel that distance, which particularly
harms individuals without access to cars or bikes.