A few more thoughts on recent discussions of density.  Better Cities and Towns offers a summary of Richard Florida’s recent speech (video is corrupted, unfortunately – it gets very choppy 1/3 the way through) at CNU. The twitter summary: quality of place trumps density.

Like previous discussions on the topic, I can’t help but argue semantics. Quality of place is no doubt extremely important – but I would argue it doesn’t trump density at all.  Rather, density is a somewhat independent variable. Density is an abstraction, it is merely the concept of how much stuff is in a given space.  For many discussions, whether on innovation or affordability or vitality, I would present density as the necessary-but-not-sufficient condition that makes it all work.  With that in mind, framing some other factor as one that ‘trumps’ (which I read as if I were playing cards: outranks, surpasses) density seems wrong.

Don’t conflate density and design: From the Better Cities and Towns summary:

One of the false statements is that density and skyscrapers are the key ingredients to urban vitality and innovation. “This rush to density, this idea that density creates economic growth,” is wrong, he said. “It’s the creation of real, walkable urban environments that stir the human spirit. Skyscraper communities are vertical suburbs, where it is lonely at the top. The kind of density we want is a ‘Jane Jacobs density.’”

What is the ‘Jane Jacobs density’?  Is it that of her home in Death and Life, the West Village?  If so, it’s worth remembering that the West Village is very dense.  The 2010 Census (easily accessed with the New York Times’ handy mapping tool) shows the West Village census tracts with population densities in the range of 80,000-100,000 people per sq. mile.

My good friend Mike Lydon linked to a review of sorts of Miami’s Brickell neighborhood, noting many of the urban design deficiencies of the place. Craig Chester writes:

Now, I enjoy Brickell primarily because I can walk for nearly all of my basic human needs – groceries, a barber, a slice of pizza etc. It’s also well-served by MetroRail and Metro Mover, both accessible from my doorstep. It’s a rare Miami neighborhood in that regard. But increasingly, I find myself questioning if Brickell is a “walkable environment that stirs the human spirit” or merely just a semi-walkable streetscape in the shadows of impersonal towers functioning as suburbs in the sky.

First, some context.  Brickell’s density from the 2010 Census tops out at 77,000 people per sq. mile in one census tract – surrounded by tracts with much lower population densities.  The max there, in other words, is lower than that of the West Village – and the West Village is bordered by residential areas with even greater population densities.

Chester continues with a number of critiques on the urban design of the area – how the buildings interact with the streets, how the retail spaces are arranged, how the neighborhood makes use of the transportation systems, and so on.  The descriptions are all fascinating, but I don’t see density as the primary (or even secondary) culprit in any of Chester’s critiques.

I increasingly find myself leaving Brickell on my bicycle in search of more authentic urban experiences found elsewhere in the city. Actually, I need to leave Brickell just to go to a bookstore or bicycle shop….

….usually found in “Jane Jacobs” density.

I’ve not visited the area so I can’t speak to the accuracy of Chester’s critique in person, but I have no reason to doubt the descriptions of the place.  However, I think the conclusion is all wrong (echoed by the language Florida uses), and sets up a false dichotomy (and therefore a false tradeoff) between density and place.  Searching for a place with ‘Jane Jacobs’ qualities is one thing, but extrapolating that to some magic ‘Jane Jacobs density’ isn’t well supported.

Don’t conflate density and the ‘human scale.’  Another tidbit from the Better Cities and Towns summary of Florida’s speech:

The urban/suburban debate is likewise false, he said. “Great communities and great neighborhoods pretty much look the same,” he said. They are human-scale, include a mix of uses, and are close to transit. “These are the kind of things that people desire, and it is not just in the urban core that you find them,” he said.

I fully agree that the urban/suburban distinction is mostly useless, but the relentless focus on the human scale is another one of those turns of phrase that can be easily misconstrued.  While there’s some relation to the absolute scale (building heights, etc), the tradeoffs between human scaled look and feel of a place (e.g. design) and the absolute mass of stuff (e.g. density) are not absolute – as sometimes implied. There’s plenty of room to go up, to be more dense, without sacrificing the human scale – the key is in how you do it.

Density (eventually) requires height, but height does not prevent place.  Alon Levy has made the point about the need for height to achieve density at some point. While there’s a tremendous opportunity for the ‘missing middle‘ in most places, many others have market conditions that already demand more space.  It’s also useful to remember that density is just an abstraction of stuff/area – the kinds of stuff you’re measuring can vary.  Tall Manhattan and short Paris are both very dense, but that’s because the tall stuff isn’t captured in the metric of population density:

Unfortunately, this point is easy to miss, since the headline figure of density is residents per unit of area, and residential skyscrapers are rare. Skyscraper-ridden Manhattan and height-limited Paris have about the same residential density, but Manhattan’s skyscrapers are predominantly commercial. Aside from project towers, Manhattan’s residential urban form is mid-rise, with most buildings not exceeding 6-12 floors; this is similar to Paris.

So, yes, we must build up at some point:

To get higher density, one must build higher. Some parts of Manhattan do: the Upper East Side and Upper West Side have a fair number of buildings in the 20-30 story range, and although as Charlie computes only 1% of New York City’s residents live above the 19th floor, the proportion is much higher on the Upper East Side and Upper West Side, and becomes even higher if one relaxes the limit from 20 floors to 12, already well beyond the limit traditional urbanists and high-rise opponents accept (Christopher Alexander proposes 5 as the limit).

Height does not prevent place – human scaled urban design can work in incredibly dense places with tall buildings, because the key elements to the human experience is what goes on at street level.  New Yorkers don’t look up at their skyscrapers because it’s not a natural position for a human.  Our HDTV screens mimic our own physiology – wide, peripheral vision with limited vertical views.  Develop the first 5 or so stories well, provide some setbacks for the taller portions above that, and you’ll do just fine for creating a sense of place at a human scale.  Adherence to this scale need not be absolute.

Beware statements of universality. It’s interesting to see one kind of density (even if people are really arguing for place, not density) pushed out as the ‘right’ level of density.  There’s a big difference between observing various geometric rules of an environment and pushing one’s taste, via observation, as if it were the rule.

The argument about the “Jane Jacobs density” is a great example.  West Village densities would represent a tremendous increase in most places around the US – just not in New York.  New York is the exceptional case.  Achieving Greenwich Village densities in other cities might be a tremendous increase – likewise, maintaining Greenwich Village densities in New York’s context (given the market conditions, etc) is likely a severe constraint on supply (see Ed Glaeser).

So, what makes the ‘Jane Jacobs density’ the right density?  How can anyone even pretend to know what that would be, without considering the context, the market conditions, the baseline of development, etc?  One element of Ryan Avent’s The Gated City that I admire was his steadfast refusal to state which level of density is ‘correct’ or ‘right’ or ‘good,’ but rather to focus on the process that cities go about changing their densities (and how that process is currently constrained by things like zoning codes).

Likewise, Ed Glaeser’s Triumph of the City focused on the market aspects of density, as far as density and overall supply are related.  So long as the cost of new stuff (housing, offices, etc) is fairly even with the cost of construction, then you’ve got a fairly efficient market.  This could be a step towards defining what the ‘right’ density is, but of course that answer is going to provide a different number in every situation.