Urban Planning

July 31, 2004 12:00 PM

Urban Planning Filter: When I first moved to Seattle, someone explained how the city managed urban growth, particularly tall buildings. [M^I]

Supposedly at some time in the past, a big table of all buildings was drawn up. Each building was given a height variance equal to its actual height. For each year that a building's owner paid their property tax in full, they got an additional 1/2 floor variance. When someone wants to build a new, tall building, they can buy variances from people who own small buildings. They then take the variances to the city, and ask for approval.

Is this how it actually works in Seattle? What about NYC, Chicago, LA, and other cities with tall buildings? It seems like a good system - real estate developers have to fight among themselves to get the variances they need. The government only needs to get involved after the developers have gone through that process and shelled out lots of dollars for the variances. Since the whole city grows by an average of 1/2 a story a year, highly speculative projects that fail are less likely.

posted by Kwantsar to Society & Culture (3 answers total)

Current Seattle Zoning Regulations for the Downtown Commercial Zone. I don't find anything like your "height increase for paying taxes" inference, but there certainly are ways to transfer ("sell", but perhaps "swap") variances from one location to another -- check out the parts about Transfer of Development Rights and Transfer of Development Credits. There certainly seems to be a Maximum FAR [Floor Area Ratio] for a given block, for instance. Certainly broad-based increases are on the political table, but not using any arcane formulae. Here's a history of urban and density planning in Seattle which may supply context.

Chicago has air rights, which normally pertain to the specific property over which a building is being constructed. Originally the concept was invented to permit buildings to be built over railroad rights-of-way; today many Loop-area structures employ air rights. Air rights are also transferable to a certain extent.

In New York, the famous period of stepped-back skyscrapers resulted not from a preference of style but from zoning regulations intended to preserve air and light as public amenities. Eventually NYC adopted a scheme of Transferable Development Rights (i.e. air rights, which included not only the space above a building where no building existed, but also -- importantly -- the space where no building would be permitted due to setback zoning) which allowed ever-higher skyscapers to be built using the unexploited space over nearby blocks. The most famous case was Grand Central Terminal, which was financed by the sale of air-rights -- but still designed with a skyscraper above in mind (e.g. vacant elevator banks), and an famous case decided that they could sell those rights again, more or less.
posted by dhartung at 12:36 AM on August 1, 2004

I don't know how Seattle did it, but the Brazilian city of Curitiba has employed some fairly effective measures to channel the placement, sizing, and density of urban buildings.
posted by troutfishing at 8:57 AM on August 1, 2004

In the case of Curitiba, it's called heavy handed central planning. The Brazilian junta running the place had a fit of foresight and decided to zone tall buildings along their busways, which are more like heavy rail on the surface than anything else. So you have central planning ensuring that the density faces the busways and their stations, gradually de-densifying outward from the stations and along the feeders.
posted by calwatch at 3:07 PM on August 1, 2004