I am a little skeptical of this data. I live in a food desert despite being 2 blocks from a Mexican grocery store and a half mile from a Food Co-op. No it's not a Safeway, but they both packed a lot of variety into ~20,000 square feet. If you can live with tortillas instead of hot dog buns (one thing I know the Mexican store is missing) then it's fine.
The solution to food deserts is not more supermarkets. Our small markets fit our community. Putting a huge supermarket+parking where they are would make walking impossible for our poor and elderly residents. A real solution is strengthening our food distribution systems so that our local stores have better access to fresh produce.
I am also skeptical. I zoomed in on Big Rapids, MI (home of Ferris State University) to find the entire town and half the campus is a food desert. How is that possible? It's a college town! It has Meijer (Midwestern chain supermarket), Wal-Mart, McDonalds/BK/Taco Bell/Little Ceaser's/etc. The on-campus eateries are open to the public for $5. Plenty of local stores and restaurants.
There's absolutely no way the downtown and campus areas of a college town could be considered "low access".
Interesting. I was initially surprised by the largest food desert in my city of residence, thinking, "that's where almost every restaurant in the city is located; my wife and I regularly shop at the Trader Joe's (upper-middle-class discount grocery store) there." But this only highlighted my blindness -- almost all of these restaurants target upper-middle class consumers, not low-income; and the only other grocery store in the area is on the wrong side of a busy highway. The only food sources targeted at low-income consumers that I know of are a few corner stores on the main thoroughfare.
I think they need to work on their numbers a little, I would consider the last option "Percentage of housing units without a vehicle with low access" the most important metric.
For example, two counties next to each other one has a 13.9 for no vehicle/low access and the other has a 0.9. Both are pink.
Not having a car severely impacts your ability to buy good produce in a food desert. Imagine taking the bus to get tomatoes, onions, potatoes etc... just not happening.
tl;dr - I think these pink blocks should be shaded from dark red/light pink based on vehicle access.
The solution to food deserts is not more supermarkets. Our small markets fit our community. Putting a huge supermarket+parking where they are would make walking impossible for our poor and elderly residents. A real solution is strengthening our food distribution systems so that our local stores have better access to fresh produce.