Guess the density – you might be surprised
Posted February 5, 2010 in Living Sustainably
We know from one piece of research after another that, generally speaking, increased residential density (homes per acre) is better for the environment. It consumes less land per capita and makes transportation (assuming the density is in a good location) much more efficient, reducing carbon dioxide and other emissions per capita. It helps limit the spread of development and pavement into natural and rural watersheds. But many Americans have a negative reaction to the word and to the concept.
In this very cool video from a presentation in Palo Alto two months ago, Redwood City (CA) planner Dan Zack takes his audience through slides of 17 residential buildings and developments, inviting the audience to guess how many homes per acre each depicts. After a pause for each, he then reveals the answer. Considering how worked up people get about density numbers, it can be very enlightening to see real-life examples.
According to this post by Irwin David on Planetizen, the video was excerpted from a much longer presentation. Now I wish I could see the rest of it. My takeaway: the density number has little relation to how well the building or buildings will fit into the neighborhood.
I wish the production quality were better, but it’s still fun. Enjoy:
Kaid Benfield writes (almost) daily about community, development, and the environment. For more posts, see his blog's home page.
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Comments
Neil Alexander — Feb 5 2010 10:39 AM
Great stuff!
For full hour see:
http://www.youtube.com/watch?v=GVmfLhZUVgM&NR=1
Daniel — Feb 5 2010 12:03 PM
I watched the full thing a few days ago. Very impressive presentation, and the message seems right on. Lincoln institute's Visualizing Density page also has lots of interesting material on the differences between our perceptions and reality.
Kaid @ NRDC — Feb 5 2010 02:33 PM
Thanks for the links!
Payton Chung — Feb 12 2010 11:13 PM
Of course housing density is something that we must properly understand, and it's a necessary precondition for so much of what makes a great city -- particularly the sustainability of services like retail and transit. However, there's a danger in making it an end rather than a mean. So many other factors, like unit size, household size, parking ratios, landscaping, and occupancy rates (a high percentage of high-rise units are second homes) can have a huge effect on how density "lives" once it's built.
For instance, the Cabrini-Green building shown is being replaced with three-story walkups that might have:
- the same DUA density
- higher occupancy rates
- higher impervious surface cover
- more living space per capita
- lower population density (much smaller households)
- higher income density (much higher household incomes)
Lower population density might mean lower transit ridership, but higher incomes mean that more retail space is needed.