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How Much Density Is Too Much Density?

2011 May 17
by Marc Weigum

Since returing home from my research trip to Hong Kong, I keep finding myself coming back to this picture:

And though the image does showcase the vast density of Hong Kong, it can’t possibly convey the true feeling a person experiences when witnessing this first hand. Even having been in Hong Kong for a couple of days, this sight really did leave me speechless.

And the numbers back up that impression: Hong Kong has a population density more than twenty times higher than Seattle’s.

Seattle, like an increasing number of U.S. cities, has begun to prioritize infill and transit-oriented development. The hope is that larger numbers of people living closely together allows for amenities within walking distance and the potential for more environmentally sustainable living where people can make trips by on foot or by taking public transit.

But, can there be a thing as too much density? While there are many proven benefits to dense urban environments, there is also the potential for negative externalities. A report from Demographia points out the world’s most densely populated cities generally score poorly on the prosperity scale (when focusing on price and income). Hong Kong while ranking 42nd in population was 3rd in density at roughly 66,000 people per square mile. For comparison, Bangladesh has 90,000, Mumbai has 70,000, and Seattle is a little under 3,000. However when ranking by gross domestic product, Hong Kong was 16th, Mumbai was 29th, and Bangladesh was in the 70s.

Of course the inverse is not necessarily any more true. Less densely populated cities don’t seem to have a greater chance of being prosperous, so there may not be a direct correlation between prosperity and density.

More data is needed to determine the level of density that is most efficient and sustainable for each unique urban area. However, the readily observable prosperity and livability of Hong Kong makes it clear that cities like Seattle have plenty of room to get more dense before worrying about too much density.


Marc Weigum is owner of Weigum Properties and an Affiliate Fellow of the Runstad Center for Real Estate Studies in the College of Built Environments at the University of Washington.

9 Responses leave one →
  1. Zef Wagner permalink
    May 18, 2011

    Wow, there is a huge problem with this post, which is the implication that somehow a more “prosperous” city is better. I would strongly disagree. If income is high in a city, that suggests it is not a place where poor people can live or succeed. Rents are too high (probably due to low density and high demand), transit is bad, energy and food prices high, etc. A great city is one that has plenty of prosperous people but also plenty of poor people, all mixed up together. It is one in which poor people can better their situation by working and becoming educated. As they move out of poverty more poor people move in from the countryside or other cities.

    Another problem is using Demographia to make any point. It took me five minutes on their website to see they are a pro-car anti-density organization. Why don’t you cite the Cato Institute while you’re at it? Find a reputable research organization to reference, not this hackery.

    • Zef Wagner permalink
      May 18, 2011

      Read Ed Glaeser’s book Triumph of the City for a lot of analysis on urban poverty. Basically, cities don’t cause urban poverty–urban poverty exists because cities are good places for poor people to live, so they choose to live there. The problem is when poor people are concentrated in ghettoes through exclusionary land use policies. Mixed-income cities like Hong Kong are great. Yes, the rich get their fancy pent-house condos, but the poor can also afford the tiny apartments. In Seattle we have such low density that many poor immigrants are forced to live in suburbs even though they would probably rather be closer to the jobs in the core.

  2. Joshua Daniel Franklin permalink
    May 18, 2011

    Marc, I’ve often asked myself the same question how much density is “too much” or “enough.” I think we need enough to support what Portland calls “20-minute communities,” where residents of a variety of age and income can meet their everyday needs within a 20 minute walk, and I think this can be done via the 50 housing net units per acre suggested guideline and a cluster of midrise mixed use buildings in a commercial area, such as in Roosevelt. I am not convinced that every mass transit station “needs” high rises however.

    I have to question whether “more data is needed” though or whether it’s simply a matter of preference. People obviously do choose to live in Hong Kong or Manhattan but also in many less dense but still walkable neighborhoods.

  3. Dan Staley permalink
    May 18, 2011

    IIRC, Marc, when I went to grad school there we had some students from Hong Kong and it was interesting to hear them speak about the density they grew up with – they felt safer because of all the people, and that density was ‘normal’ to them. Even at lunchtime on the Ave it wasn’t (comparatively) crowded.

    IOW: its what you’re used to. When I used to visit Manhattan, it was overwhelming alone, and I sure was glad I had someone there to take me around…

  4. May 19, 2011

    Is there such a thing as too much density? Maybe, but in the U.S. it’s hardly a pressing problem. Many of the infill cities are struggling for 5 story buildings. It is worth noting, for those advocating walkability and transit, 5 story buildings can be enough in many places. A wise developer told me that it doesn’t make any sense to put all your eggs in one 20 story building in a downtown with lots of vacant lots when you could build four 5-story buildings with the same program and created a place worth walking in. Somewhere down the line someone may knock one of those down and build a 20 story building after the neigbhorhood is built out.

    If the market is not overly constrained I think it’s a poor decision to try to limit density for fear of livability decline. People choose to live in cities for a variety of reasons and as wealth fluctuates they will be willing to live at different densities with different conditions and amenities.

    You also have to distinguish between building density and people density which can vary drastically. The person density of many cities has dropped drastically as family sizes shrink and wealthier people knock down walls to create bigger apartments. Of course the reverse happens as well; multi-story townhouses are subdivided into flats. The law should allow this to happen letting the same built environment serve different users and densities over time and making neighborhoods more resilient. In other places what appears to be a lot of built density is masking a lot of structured parking.

  5. g_dub permalink
    May 19, 2011

    Ironic for you to post this – you of the more-density-everywhere in Seattle mindset. I love dense communities too, but there’s not unlimited, endless demand for growth in this region in the next 5 minutes. Seattle’s zoned capacity already dramatically outstrips the amount of growth we could ever reasonably see in the next several decades. Density pushers in this town need to chill a little and understand the actual dynamics of growth in the region. We’re not Hong Kong, New York, Sao Paulo, Mexico City or even Chicago. There are no alarm bells going off saying we need post tension concrete towers in every urban village. Maybe this post is a recognition of the density feeding frenzy among the kids that you’ve helped to create.

    • dan bertolet permalink*
      May 19, 2011

      g_dub: I’ve written a lot about density but never have I said that density belongs everywhere in Seattle, or that Seattle needs to be just like Hong Kong or NYC, etc. The fact that you try to use that straw man says more about you than me.

      I do however, believe that “post tension concrete towers” have a place in urban villages that have light rail stations. Do you?

      • g_dub permalink
        May 19, 2011

        Maybe a few decades from now, but not necessarily at the moment. And it would need to come through a reasoned comprehensive plan level discussion – not spot-by-spot fenzy about density this instant. Fact is we’ve got many holes in the gound citywide that can accommodate mucho capacity and that doesn’t even start to scratch the surface of the reservoirs of auto-corridors vacant strip malls and urban nowheres region-wide that we could fill first. Seattle overestimates the amount of density it needs to accommodate in the near term is basically what I’m saying and the numbers support that if anyone wants to look at them.

        • dan bertolet permalink*
          May 19, 2011

          In your view, how much density is appropriate at Yesler Terrace? Do you think residential towers make sense there? I do.

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