There’s a new tool for viewing information about census tracts

A new website created by artist and urban planner Neil Freeman lets users view information about density, the built environment, and commutes from the Census's 2014 Five-Year American Community Survey.

Since the website only shows one tract at a time, it is not the easiest way to get the feel of an area one isn't familiar with. However, if you have an interest in a particular neighborhood or region, the information presented can be quite illuminating.

Population and housing density

Along with the usual population density, Freeman's site presents some other information about the housing in a given Census tract. In particular, it provides housing density: both as number of housing units per square mile, and as median number of inhabitants per housing unit.

The website also presents median income and median cost of housing (regardless of whether it is rented or owned) for Census tracts. This shows some interesting patterns, including the very large differences in income and cost of housing between tracts on opposite sides of Rock Creek Park. However, one unfortunate problem with the income and cost-of-housing data is that they're not directly comparable to allow one to figure out how rent-stressed the Census tract is.

Median income is presented as calculated for people 15 and older who have income. However, median cost of housing is provided for housing units with known housing costs. Although data is also presented on the median number of people in a household, it is not possible to know how many incomes the median household has, so is isn't really clear what housing affordability for the median household is.

The website also presents information about the median age of housing units in a tract. However, it is important to keep in mind that this is calculated per unit and not per building. A large apartment building surrounded by single-family homes may contain the majority of housing units in the area.

Furthermore, there appears to be some kind of glitch or simplification that shows that all residences built before 1939 have been built in 1939. Georgetown and almost all Census tracts between the Capitol and the Anacostia list this as their median year of construction.

You can suss out interesting commuting patterns

While commutes to work are not the only trips people make and the availability and use of transit for other trips is important, there is a tendency to focus on commutes when discussing mode share. In part, this is because the American Community Survey asks residents what mode they use for the longest part of their commute to work. Freeman's website provides this mode share information for each Census tract, and I noticed a few interesting things in it.

Eighty percent of Americans drive alone to work, and there is a tendency to think of most people's commuting options as being driving or transit. However, the Census tract in Langley Park that contains the year-old Takoma-Langley Transit Center has a 50 percent carpooling mode share, with 21 percent of commuters using public transit and 24 percent of commuters driving alone. (Only 2 percent of Americans live in tracts with lower percentages of commuters driving alone.)

I'd be interested to find out more about why the rate of carpooling is so high in Langley Park. Presumably part of the answer is that the area is both poor and very dense, so many residents likely don't own their own cars and live near people who work in the same area as them. However, the fact that nearly two-and-a-half times as many people carpool as ride public transit in an area served by a number of bus routes and a newly-built bus station seems to indicate that bus service in the area is not effectively serving residents. Hopefully the Purple Line, which will have a stop at the transit center, will help with this.

What patterns do you see in this data?