Friday, March 15, 2013

Why Density Matters

What's the question? Density is the answer. Kaid Benfield takes aim at this peculiar urbanist cult:

A few days ago, I was reviewing some good work by colleagues describing NRDC’s advocacy for sustainable cities. The original draft stressed that dense living is the way to go. Wherever the word "dense" appeared, I crossed it out substituted the word "walkable." Not only is "walkable" a much friendlier word; it also captures so many more of the things we need to make the places where we live and work more sustainable and livable.

I think "walkable" is also well on its way to becoming a cliché. I digress. We've lost sight of why density matters. Benfield refocuses attention on goals of sustainability. In that view, density is beside the point. Walkable is a more useful concept.

The lust for density is pornographic. The best example is Tony Hsieh's Las Vegas project. Density solves everything. He conflates occupational density with residential density:

Tony Hsieh talks about his Internet juggernaut Zappos in the same way that urban planners talk about cities. In fact, the language is uncanny. He believes the best ideas – and the best form of productivity – come from "collisions," from employees caroming ideas off one another in the serendipity of constant casual contact.

This is only achievable through density, with desks pushed close together in the office, or – in the case of Hsieh’s ambitious plans to leverage the new Zappos headquarters to remake downtown Las Vegas – with company employees and community members colliding into each other on the street. For the kind of "collisionable" density he’s looking for in downtown Vegas around his company, he figures the neglected area (not to be confused with the Vegas Strip) needs at least 100 residents per acre.

If office density fosters creative thinking and greater productivity, then residential density should do the same. Right? Wrong. Hsieh's reasoning is specious.

Mind you, we're not talking about sustainability anymore. The issue is innovation. I'm open to reading some research the demonstrates a density dividend for residents. I haven't seen it. Occupational density is another story:

We have examined three reasons why firms may be willing to pay more to workers in bigger cities. First, there may be some static advantages associated with bigger cities. Second, bigger cities may allow workers to accumulate more valuable experience. Third, workers who are inherently more productive may choose to locate in bigger cities. Using a large and rich panel data set for workers in Spain, we provide a quantitative assessment of the importance of each of these three mechanisms in generating earnings differentials across cities of different sizes.

Emphasis added. The effect for workers exists regardless of where they live. The benefits of agglomeration can be found in metros of tremendous sprawl. Residential density is irrelevant. Tony Hsieh is hunting snipe.


Pete Saunders said...

Jim, I get where you come from on density. Increasing density by itself doesn't promote greater economic productivity. But many planners look not just at that but also at service delivery efficiency for municipalities. The costs to cities of roads, water and sewer lines, schools, parks and the like increase drastically at lower densities. Denser cities do operate more efficiently. I'd encourage you to check out, a blog by a civil engineer who makes this argument very persuasively.

Jim Russell said...


I see the value of increasing residential density. I'm aware of the tremendous cost burden resulting from residential sprawl. I don't take issue with that line of thinking. More efficient allocation of a scarce resource such as water makes a world of sense. You offer a few great examples of why density matters.