Mapping Food Deserts by Drive Time: Takeaways From the SDOH and Places Symposium
Written by Jaelyn Braswell, Data Analyst at Metopio
I recently had the privilege of speaking at the third annual SDOH and Places Symposium in Chicago, IL. It was my first time attending, and it didn’t disappoint. The three-day event was packed with networking, workshops, lightning talks, sessions, and fellowship presentations on the latest in public health GIS research.
Some of my favorite moments were meeting fellow public health folks and learning about their work. I got to meet the passionate and kind Beth Beyer from the TEC Alliance, who introduced me to her work bringing sound into community spaces to support holistic health and environmental justice. One of the goals of her project is to elevate people's experiences in green spaces and help them feel more connected to the nature around them, hopefully enough to inspire them to take action. I also met the funny and brilliant Ben Spoer from the City Health Dashboard, this year's keynote speaker, who gave a memorable talk on the emotions behind data dashboards and why that matters at a time when public distrust of government and public health agencies is so high. Every presentation I saw connected back to the equity-focused work I do at Metopio, and a few sparked some fresh ideas: better dashboard practices, more human-centered approaches, and new measures in lesser-explored corners of public health, like linguistics, hourly access to grocery stores and health care facilities, and the intersection of heating, cooling, and health.
My talk was part of the Poverty and Policy session, and it covered a recent project where I used drive time to identify food deserts. Funnily enough, I learned while I was there that drive-time access is the hot new way to measure access — so the timing couldn't have been better.
Here's the synopsis:
“Food deserts” are areas where people have limited access to affordable, nutritious food, and they're linked to poorer diets and worse health outcomes. That makes identifying them accurately a public health priority. The standard approach comes from the USDA's Food Access Research Atlas, which flags an area as a food desert when it's both low-income and low-access (known as the LILA criteria). The catch is that the 2019 USDA measures access using straight-line distance, which ignores how people actually get around. Roads don't run in straight lines, and rivers and mountains get in the way. Drive time gives a much more realistic picture of how accessible a grocery store really is.
For this project, I kept the USDA's LILA criteria but swapped in drive time as the access measure, using current, publicly available data. I calculated drive times from census block centroids to grocery stores along the actual road network, then rolled the results up to several sub-county geographies, including Chicago's community areas.
I found that in Chicago, 2.8% of residents have low access to grocery stores, and 1.5% (42,471 Chicagoans) live in food deserts. Non-Hispanic Black residents experienced food desert exposure at 3.1%, about twice the citywide rate, and community areas on the South Side, including Burnside, Riverdale, and Pullman, had the highest shares of residents living in food deserts. These results line up with past research showing that low-income areas are disproportionately cut off from healthy food. By pinpointing these gaps at the sub-county level, a drive-time approach gives public health practitioners and policymakers a precise tool for getting resources to the communities that need them most.
How Can You Use This Information?
This project isn’t just specific to Chicago. The food desert data covers the entire country and is available on Metopio's platform at the US, state, county, ZIP code, census place, and census tract levels, plus Chicago's community areas. You can find it here.
Alongside the percentage of the population living in food deserts, we also publish four related topics:
Drive time to the nearest grocery store
Population living in food deserts (count)
Low access to grocery stores
Very low access to grocery stores
And since drive time turned out to be such a useful approach, we applied it to health care, too. You can also find low access to hospitals, stratified by hospital type.
The data for food access currently covers 2024, and we plan to publish updates annually, so do keep an eye out as new years roll in.
Final Notes From the SDOH and Places Symposium
The thread connecting so many of the talks I saw, mine included, was a push to make data reflect how people actually live. I left the symposium energized, full of new ideas, and already looking forward to next year.
And none of this would have happened without some amazing people. I’d like to give a huge thank-you to Metopio’s COO and co-founder, Angie Grover, for introducing the opportunity, the Metopio data team for supporting every step of the work on this project, as well as my Data Analyst colleague, Jess Post, for being in my corner at the symposium. And of course, thank you to the organizers for putting together such a thoughtful event, and to everyone who stopped by to chat. If you're working on something similar, I'd love to connect with you!
You can connect with Jaelyn on LinkedIn by accessing her profile here.