[h/t Kaid and Irwin Dawid/Planetizen for the video of Dan Zack’s density game]

Of course housing density is something that we must properly understand, and it’s a necessary (but insufficient) 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.