EXd-ize

One of the issues with broad, sweeping, simple policy changes is that as soon as the “broad” change is implemented, people immediately start trying to carve out exceptions.

When you look at “full Houstonization” – removing zoning in a metropolitan area that has traditionally had it – you have to consider these effects. So for instance, let’s say for the sake of argument that zoning was removed in all of the ADAG counties – yes, it would never happen, but that’s what “for the sake of argument” means. What would be the result? Well, it’s not too hard to figure out that almost every slice of postwar single-family residential would be immediately declared “historic” and off limits. For instance, here’s a screenshot from the recently released NCHRP 723: A Model for Identifying and Evaluating the Historic Significance of Post-World War II Housing:

We're doomed.

“A Planned Neighborhood of Affordable Housing.” So, basically every subdivision ever built, ever. By contrast, there’s a lot of developable land in the hills around San Jose. A lot of is in private ownership, and it’s hard to argue it’s a “historic district” when there’s nothing there. There are also substantially fewer people to mount a NIMBY campaign to prevent development in these areas. For sure, there’d be letters and petitions, “Save the Santa Cruz Mountains” and so forth, but ultimately people make a bigger fracas about their own… backyard.

Without taking any kind of stance on whether a ten-lane Highway 17 would be a negative or positive development, I think it’s reasonable to surmise that dezoning coupled with deed restrictions and historic districts would on net increase sprawl in the Bay Area.

How, then, to mitigate this? One alternative, crazily enough, comes to us from Portland.

EXd in the Portland zoning heirarchy stands for Central Employment with Design Review. What is Central Employment? I quote the code: “The zone allows mixed-uses and is intended for areas in the center of the City that have predominantly industrial type development. The intent of the zone is to allow industrial and commercial uses which need a central location. Residential uses are allowed, but are not intended to predominate or set development standards for other uses in the area.”

This… is a lie. Any part of Portland where residential doesn’t “predominate” is going to be zoned IG1 or some other traditional Euclidean classification. EXd is for dense, mixed-use neighborhoods like the Pearl District or the South Waterfront. But the code needs to say that as a retort to newly-arrived NIMBYs who might otherwise complain that a longstanding industrial neighbor is an “incompatible use.” It’s a useful legal fiction.

What can EXd do for you? Well, one of the big benefits of Houston’s non-zoning is that there’s a lot of reasonably dense redevelopment everywhere. In closer-in areas you get the walkable mid-rise that so many other cities spend decades planning for, and in more outlying areas you get a heterogeneous mix of townhomes and teardowns and rehabbed garden units and pedestrian-friendly strip centers. Since almost every American city has a planning and zoning regime that preferences low-density, sprawling development, what you want to do is start off by allowing a substantial amount of redevelopment in existing areas and then allow more outward expansion as formerly single-family neighborhoods closer in bulk out. An EXd type zone is perfect for exactly this.

Allowed uses: Pretty much everything

As you can see, EX allows essentially everything except quick lubes, u-stor-its, recycling centers, and public parking garages.

Are there problems? You Betcha. For one, Portland confines EXd to a few “headline” urban districts, and the exclusions reflect that. In a broader EX type zone there isn’t any good reason to ban gas stations or oil change places. Mini storage units are one of the most compatible land uses known to man, and will happily nestle up to everything from residences to refineries. And the conditional use requirement for public parking facilities seems to reflect a particularly Portland skittishness about parking. If you’re going to eliminate minimum parking requirements, you also need to allow for standalone public garages to fill latent demand for spots.

Portland’s EXd also contains a 65′ height limit. Portland tends to avoid tall buildings in general, perhaps out of fear that they will block someone’s view of Mount Hood. But good lighting and air circulation are better achieved with slender towers than blocky mid-rises. Where a block of 4:1 FAR might translate into a six-story mid-rise with a central courtyard, that same 4:1 FAR could be a single story of retail with a slender 20-story tower rising out of one corner of the lot. The latter casts far less of the adjacent streets in shadows as the sun moves through the sky.

But regardless of the specific issues with EXd as applied by Portland, the basic concept of creating one broadly inclusive zone for redevelopment is useful for almost every American city besides Houston. In a city with intricate, parcel-by-parcel zoning like SF, a big chunk of EXd would be a breath of fresh air.

5 thoughts on “EXd-ize”

  1. Short of having no zoning at all, I think these types of “General Urban” zones are a great solution for American cities trying to increase densities and urbanize while working within an established zoning framework. Nashville has adopted a similar zone for its downtown and surrounding ex-industrial areas in connection with abolishing minimum parking requirements, and I believe other cities have been considering and adopting them as well.

    I will say, though, that I’d be generally supportive of reasonable height limits in a situation like this, as they seem encourage development by limiting speculation and setting common expectations (this is rarely if ever the motivation for adopting them, but it does seem to be their effect). A forest of slender towers is an appealing vision, but very few urban markets have the sort of demand and land scarcity necessary to make that a reality on any significant scale. If sacrificing a handful of towers does in fact accelerate urbanization, I think it’s a deal worth taking. Unfortunately, there has not been much written about the economics of height limits since the 1920s (a healthy debate was cut short by the Depression, and never really resumed afterwards), but here’s one guy taking a crack at it:

    http://blog.lib.umn.edu/levin031/transportationist/2011/10/height-limits-produce-a-positi.html

  2. Levinson makes a really interesting argument there. I can certainly see the appeal; one of the lasting impacts of the Main Street LRT line has been that there are still a number of vacant lots throughout Midtown within the LRT walkshed.

    But there’s a number of issues. For one thing, you don’t need land scarcity for slender towers. The Mercer is wedged between a gas station and a typical garden apartment complex; it’s there because there’s a market for condos with a view. Likewise, there’s no guarantee that height limits will lead to an engaging street environment. Camden Travis Street checks all the right urban planning boxes – mid-rise construction, articulated facade, natural materials – but scarcely engages the street at all.

    Meanwhile, adopting height limits as a means to accelerate development seems like a Faustian bargain. Even if it succeeds, it closes off the area to future upzoning. No one protests a high-rise in Midtown or Uptown or Westchase because those areas are a hodgepodge of every conceivable building type. But one attempt to put a tower in a fairly homogenous neighborhood of two-stories lead to years of outcry and a smattering of new building regulations which will hamper new development in H-town for some time.

    Going back to Washington, it’s one thing to make a theoretical argument that more of the city should be built out at 90 or 130 feet before towers are allowed. But in practice most of the city is zoned for far lower FARs and height limits and any attempt at going beyond those results in years-long permitting processes where individual neighborhoods demand concessions and kickbacks. Put in height limits now and you’ll run into the same issue 20, 30, or 50 years down the road when the area is built out.

  3. You don’t need land scarcity for towers, no, but you do need a very high degree of scarcity before residential towers become a characteristic or at least common development type within a neighborhood (that is, where the towers are built due to land scarcity rather than simply demand for views, which seems to be a negligible proportion of total residential demand in most cities).

    And I completely agree that height limits do not guarantee good urbanism – I wasn’t arguing that they did. However, if a handful of towers soak up limited residential demand for urban living, it makes a continuous urban fabric that much harder to achieve. A greater worry is that sellers in high-demand areas will all price their land in expectation of a high-rise, even though the market may only support one or two. This paradoxically results in developmental paralysis in the highest-demand areas, abetted by property tax laws which reward landholders for sitting on vacant land – again I would cite Nashville as a case in point.

    I wouldn’t worry so much about future upzoning, either – once you have a neighborhood like the Pearl District established, if it became necessary or desirable at some distant point to add more height, it would be much easier to do so there than in the typical neighborhood of single-family detached houses. This is implicit in the debate in DC, where advocates for loosening height restrictions appear to want them relaxed in those areas already set at the highest levels, rather than raising up low-rise areas to the levels of the CBD (that is the logical implication, since almost all cities have height limits outside the CBD, as DC also does, yet only DC limits them to the extent it does in the CBD itself).

    The Ashby high-rise situation I think shows that a city without any height limits or restriction may actually not be politically possible over the long term in a society where land use is controlled at the local level. I posted on this before, but in many cases, building restrictions, height limits and zoning in general were imposed after a developer built or tried to build a tall apartment building in an affluent low-rise area. That is precisely how Washington, DC got its Height of Buildings Act, for instance. Nothing sets off the NIMBYs quite like it. Better for a city to get out ahead of the NIMBYs rather than passing bad laws that hinder development in a fit of overreaction.

  4. I think I see what you’re getting at here. If you’re starting with single-family low-rise, restricting building heights at the time of the upzone could blunt some opposition. Then later there would be some opposition to allowing towers in the mid-rise district, but the sum of the oppositions might be less than the Mortal Kombat-style battles to the death that high-rises in affluent single-family neighborhoods entail.

    Makes sense.

    But two caveats. First, how much of the residential demand gets “soaked up” by a single project is a function of FAR, not of height. If I have an acre lot subject to 4:1 FAR, I’m only building 175k SF of space. Whether that gets built as a 6-story block or a 30-story tower is irrelevant.

    Second, that argument really only makes sense if you’re converting an existing single-family residential neighborhood. If the base zoning is restricted industrial – something like Dallas’s Stemmons Corridor, for instance – then there’s no reason to add the restriction except a desire to ban towers qua towers.

  5. Did you pick that Google Streetview of Bissonnet because you can see an anti-Ashby Highrise banner on a fence, or is that just a coincidence? 🙂

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