Density is Destiny

Economically, cities have a certain magic we don’t yet fully understand. In his Wall Street Journal piece Urban Planet: As World Crowds In, Cities Become Digital Laboratories, Robert Lee Hotz quotes some key urbanists thus: 

By studying dozens of per capita measures world-wide, Dr. Bettencourt and theoretical physicist Geoffrey West detected a fundamental pattern underlying the growth of all cities, from ancient Mexico to modern China. In studies over the past 12 years, they determined that every time the population of a city doubles, every individual measure of human interaction there also increases by 15% to 20%.

Not so long ago, futurists predicted that the ease of electronic connectivity would make big cities obsolete. Instead, Harvard University economist Edward Glaeser and others now say that improvements in information technology strengthen cities that are centers of innovation by speeding the flow of ideas. Urban density facilitates contact between smart people and fosters innovation, increasing urban incomes as new businesses take hold, they say.

“With cities, we increase the possibility of more interactions among ourselves, to create the buzz of a city, to create more ideas, more wealth. That is the attraction of a city and why they are so successful,” says Dr. West.

It stands to reason that whatever the magic of cities consists of, it has something to do with people being close to other people or people being close to things. And the way to have many people close to one another is to have a high density. (However good transit is, distance is always going to matter for travel times.) So a key goal for architects who want to build a prosperous future is to figure out ways to make high density both inexpensive and delightful. 

To my taste, to have high density be delightful, there are five key desiderata:

  1. plenty of floor space in the home
  2. no stairs within an individual family’s home (particularly important given the aging of the population)
  3. plenty of windows looking out
  4. excellent soundproofing
  5. plenty of green space nearby

All of these are compatible with very high density, given good design. The key is to have no height restrictions. Instead of the usual condos or other multifamily dwellings where one or two wall’s worth of windows are lost, and inhabitants would be either driven as they age or doomed to climbing stairs in their old age, build buildings in which each family has exactly one floor. Different buildings can have different sized cross-sections to allow for families at different income levels. Three or four such buildings can be arrayed around a common elevator shaft (that also has stairs for emergencies) without losing too many outward-looking windows.  

Of course, hearing the family above is no treat. So excellent soundproofing is a must. But modern technology has provided many materials that could be used between floors to provide very effective soundproofing. The key here is to provide enough information on noise levels in building to give builders and building owners enough incentive to put sound-proofing in and take other common-sense steps to keep noise down. What is needed is something that I think could make someone a tidy amount of money right now, relative to the cost of doing it: an app that lets people give noise ratings for their experience in a home they are renting. The business model is similar to a website such as The one difference is that this would be (I think that name might actually be available.) I would love to hear about any such app or website that already exists, and if it doesn’t exist, and anyone builds it, I will advertise it with a blog post here. 

Building up allows green space to be maintained on the ground. But the other way to provide a lot of green space in the city is to have green space on the roofs of buildings. It would be great if many of these green spaces on the roofs of buildings could be common areas for all of the residents of a building to enjoy, not just the family in the penthouse apartment.

Given a wise city policy to encourage such buildings and therefore essentially automatic approval for buildings designed on this basis that are fundamentally like other buildings that have already been built, the remainder of the task of making them inexpensive comes down to architectural and engineering innovation. As long as the buildings are tall enough, land prices shouldn’t be too big a problem. It is just a matter of being able to build the physical structure in an inexpensive way–partly through some degree of standardization, and partly through the use of stronger, cheaper materials.

Even as things are now, I think Manhattan is very pleasant. With residential buildings like the ones I am describing, almost any city could have high density and be even more pleasant than Manhattan is now–except for one thing: as long as each family gets plenty of floor space, no stairs to climb, plenty of windows, excellent soundproofing, and plenty of green space, when it comes to cities, bigger is better. And New York City has a head start.