Screen capture of the car-free commute map for my current home, Los Angeles

My NCAA bracket came to a close yesterday (curse you, Michigan State), so it's fitting that March Mapness come to a close as well.

I've been working over the past month on uploading census tract boundaries for every state in the US, and Washington DC, and creating some nifty maps to show what that boundary data can be used for. Now all those maps are complete, so I compiled them into one mega-map of all 72,000 census tracts in the United States, categorized by the share of commuters who get to work by foot, by bike, or by public transportation — anything that doesn't involve a car. The colors divide census tracts into those with less than a 5 percent car-free commute share, then 5 to 10 percent, 10 to 20 percent, and so on.

Keep in mind that this map is for commute data only, so trips other than for work and school are not included. Unfortunately, that's the best the American Community Survey can offer at this level of resolution. Hopefully in the future they begin to gather data on all trip types, not just commutes. In the mean time, commuting hours are when the largest numbers of people are on the road and congestion is at its worst, so knowing how people are getting to and from is still very useful. This kind of information can be used as a first step in deciding where to place bike share stations, where to prioritize bicycle lanes or pedestrian improvements, where bus-only lanes may be warranted, you name it. Where car-free commutes are less common, it can identify seed neighborhoods that lead their city in active or public transportation use and would benefit most from investment in these modes.

With all that in mind, here's the final product:

To see the map in a full screen, click here.

The purpose of this was to provide a resource, not just in the maps themselves, but in the census tract boundary data that underlies them. I hope that readers will make use of these data to create their own localized maps of whatever they can think of. Be creative! As the amount of data we collect increases, the number of things we can visualize in interesting, meaningful ways continues to grow.

This was also a learning experience, and I've become much more familiar with Google Fusion, the free app I used to create these maps. If you'd like some guidance on how to create maps of your own, feel free to email me with your questions.

The map itself is a resource, of course, and I encourage readers to share it broadly, however you like. No permission is required, but a link back to this post would be appreciated. Post it on your own blog, share it with your local public transit agency and active transportation advocacy organizations. Call your senators! Call your mother! She misses you.

The mode share data is also freely available, and it's easy to embed the maps wherever you like.

For those interested in embedding the map on your own site, you'll want to go here, click the tab that says "Map: Car-free Commutes, all US census tracts," pull down the tab that says "Publish," and copy from there. The embedded map will show whatever you're looking at when you hit "Publish" — in my case I was viewing Seattle, for example — so keep that in mind if you want to highlight a specific area.

Here's some more information you may find useful: This is the link to the full list of US census tract boundary data, which can be merged with any data you find that's got a census GEOID associated with it. (All Census/ACS tract-level data includes a GEOID.)

And this is a brief tutorial on how to use Google's Fusion Tables. It's not the easiest thing to figure out right away, and the tutorial is a bit outdated, but compared to something like ArcGIS it's a breeze. The functionality isn't on the level of GIS, but you can do some pretty amazing things with very limited knowledge/expertise.

Commute data was taken from the 2012 American Community Survey 5-year data set, which averages data collected from 2008 to 2012.

Census tract boundary data was taken from Census.gov, here, using the generalized (not detailed) boundaries.

Last, if there's anything you feel is missing, or questions you'd like cleared up, don't hesitate to email me. Enjoy!

UPDATE:

I've added maps for public transit, bicycle, and walking commute mode shares. I didn't include those who work at home in the counts for the car-free mode share map, because they don't technically commute, but I made a map of that as well. All of them can be found below. Note that the scales vary, so while a purple census tract in the car-free commute map may represent 50-percent-or-higher mode share, for example, on the public transit map it represents only 30 percent or more.

Public Transit Mode Share

Walking Mode Share

Bicycle Mode Share

Work at home mode share

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