Measuring Vulnerable Population's Healthy and Unhealthy Food Access in Austin, Texas.

Food deserts-areas with a significant low-income population experiencing low accessibility to healthy food sources-have been well studied in terms of their connection to obesity and its related health outcomes. Measuring food accessibility is the key component in food desert research. However, previous studies often measured food accessibility based on large geographic units (e.g. census tract, zip code) with few transportation modes (e.g. driving or taking public transit) and limited vulnerable population measures. This paper aims to demonstrate a new method to measure food access for different vulnerable population groups at a smaller geographic scale with different transportation modes. In detail, this paper improves on previous studies from the following three perspectives: (1) Measuring food accessibility with a smaller geographic scale: block group vs. census track which on average includes 1000 people vs. 4000 people; (2) Measuring food accessibility with different transportation modes: walking, biking, transit, and driving vs. driving only; and (3) Measuring food accessibility for different vulnerable population groups. The proposed method was tested in the city of Austin, which is the capital of Texas and the 11th largest city in the US, and measured people's accessibility to both healthy and unhealthy food sources within the city. The methods can be applied to address food accessibility issues in other cities or regions.