Prince of Wales Promotes Health, Wealth, and Courtesy

I'm starting to like HRH the Prince of Wales. Or maybe I like Hank Dittmar, the head of the Prince's Foundation for the Built Environment, who I suspect is the brains behind the operation. Hank Dittmar is still Chairman of the Congress for the New Urbanism, and has been president of the Center for Transit-Oriented Design, a founder of Reconnecting America, executive director of the Surface Transportation Policy Project, on the White House Advisory Committee on Transportation and Greenhouse Gas Emissions and chair of the Metropolitan Working Group of the President's Council on Sustainable Development. He probably knows what he's talking about.

A few weeks ago, the Prince gave a controversial speech in which he condemned the spate of new residential towers of nine to twenty stories and the "buy to let" investors and the urban planners who seem to promote them. He drew the parallel between courtesy and good manners between individuals and what he calls vandalism against the heritage and remaining beuatiful areas of our cities. He gave several arguments in favour of adaptive reuse of existing building rather than redevelopment, and of building adaptably for the long term, one hundred years rather than twenty. He wants new construction to fit into the existing context.

And, finally, it is worth understanding the purpose of a building, or group of buildings, within the hierarchy of the buildings around it and responding with an appropriate building type and design. Doing this often implies the composition of a harmonious whole, rather than the erection of singular objects of architectural or corporate will which merely panders to ego-centric imperatives.

He discussed the principles of planning the entire built environment, with public spaces, a mix of uses within walking distance, legibility and proportion, mix of private, social and affordable housing. But he was particularly scathing about tall buildings near heritage sites, but not against tall buildings in general, which he thinks may be suitably clustered a bit outside the old city. His reasons for objecting to tall towers, especially residential ones, are not all aesthetic but also social and environmental.

Many people believe, erroneously, that the only way to achieve environmental efficiencies in development is by building very tall buildings. Indeed, improving the average density of building in England is critical to achieving "location efficiency," which reduces automobile use and greenhouse gas emissions, as well as minimizing land-take. But these efficiencies only begin to occur at 17 units to the hectare, when public transport becomes feasible, and begin to tail off at densities above 70 units to the hectare, according to a definitive research study from the United States which has recently been applied by my Foundation in a London project. This is because achieving environmental gains is a function of density, access to public transport and walkable, connected streets. Pedestrian street access becomes more difficult at higher density.

This definitive study is probably one by Dittmar and others that I've mentioned before. In my opinion that study is qualitatively right about diminishing returns at the higher end of the density scale but overestimates even the small effect of residential density on transit at the highest end on the scale.

The Prince's Foundation doesn't just follow the latest fads or the current likes and dislikes of someone who happens to have been born into the royal family. It follows an established design theory that is thoughtful and progessive.

The latest news is that the Foundation is embarking on a new project, called Knockroon (isn't that where James Boswell used to live?) in Scotland. The new town will specialize in healthy living, where everything is walkable and cycling is de rigueur. This is intended to demonstrate how the built environment can affect health. And presumably it won't have any tall towers being discourteous to the existing historic Dumfries House (pictured).

Tags: Urban Planning Urban Design Walkable Skyscrapers New Urbanism

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Physical Measures Reduce Trips by How Much?

In an often-quoted study by Nelson\Nygaard it is said that physical measures such as net residential density can be used to reduce trip generation by up to 90%. I have often wondered about this figure, and I went to check the article. Unfortunately, the study says just that but the data on which it is based can not be used to support this hypothesis.

Here is the data from the table that makes the claim. Net Residential Density can reduce trip generation by "Up to 55%", Mix of Uses by "Up to 9%", Local-Serving Retail by "2%", Transit Service by "Up to 15%", Pedestrian/Bicycle Friendliness by "Up to 9%", which all adds up to 90%. Add in "Affordable Housing" (Up to 4%) and Free Transit Passes (25%), and you've reduced trips by 119%!

Catch the flaw in logic? The maximum values of these reduction ranges are not additive, unless you can prove that they are independent. I think it's pretty clear that density and transit service, for instance, are not independent in the figures on which these reduction factors are based. If they're not independent, the reductions aren't additive. In fact the individual reductions would be lower.

What exactly are these figures based on? Well, for density this is the difference between the highest and the lowest density area (assuming that everyone currently lives in the lowest density area and all of them will move to the highest-density area) calculated using the single-parameter formula from the paper Holtzclaw, Clear, Dittmar, Goldstein, and Haas, "Location Efficiency: Neighborhood and Socio-Economic Characteristics Determine Auto Ownership and Use - Studies in Chicago, Los Angeles and San Francisco", Transportation Planning and Technology (2002). This study was quite clear that the effects of socio-economic characteristics, transit, nearby shopping, and so forth could not be disentangled. It also discusses studies showing that variations in household size and income are more important than transit or density. They say that area-wide studies show that doubling the density of an entire metropolitan area would reduce VMT by about 20-25%. Would further doubling further reduce it by the same amount? No, it is quite clear in the paper that the relationship is not linear but logarithmic. Virtually all the reduction in trips occurs at very low density - you get four times as much decrease in going from very low density to about 20 households per net residential acre than you do by going from 20 households per acre to 200.

I won't even talk about self-selection bias nor about my own papers that measure the fact that when you look at apartment residents and house dwellers separately, the density effect is almost entirely in the house dwellers. Good thing because that means we can do something about that given that they are the majority and are unlikely to want to live in apartments. If apartments are all we build, driven by a simple-minded belief in provably incorrect linearity, we will only drive the majority further away. Of course if we want to concentrate on the single housing form with the lowest VMT, we should be building nothing but homeless shelters.

Enough of that. These effects are neither linear nor additive, but they exist. Just for fun, I looked at the Nelson\Nygaard Table 3, which shows the trip rate as a function of land use, but also shows, for each of the land uses from Single-Family Detached Housing to High-Rise Apartment, the values for residential density, housing units, jobs, presence of retail, index of transit service, intersection density, sidewalks, etc., and did a multiple linear regression on their predicted average trip generation figures. The result is that transit, jobs, and intersection density explain virtually all the trip generation data, density is not really a factor at all, and the transit index by itself is an excellent predictor.

Tags: Urban Planning Urban Design Walkable LEED-ND Transportation

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Tall Buildings Incompatible with New Urbanism

The Congress for The New Urbanism seems to have had heated discussions on whether they should officially take a stand on vertical buildings, according to the latest issue of New Urban News.

"I'm sick and tired of seeing 'green' skyscrapers," says Ben Pentreath, director of Working Group, a London-based architecture and planning firm. "CNU should have a stand against vertical buildings." Working Group produces traditional-looking houses that satisfy stringent energy standards, and has built more than half the houses that have won UK Home Excellence awards. Traditional houses, he says, do a much better job of creating appealing streetscapes and saving energy. Traditional houses, with their greater proportion of solid walls and less glazing, get energy efficiency with less effort. "They're cheaper to build, quicker to build, and they sold for more money," Pentreath said.

Elizabeth Moule and Stefanos Polyzoides, partners in Moule & Polyzoides Architects and co-founders of the the Congress for The New Urbanism, proposed that CNU oppose buildings of more than about seven to 10 stories, to avoid what Polyzoides termed "loose tower disease" - erecting tall buildings without pedestrian-oriented streetscapes between them. Hank Dittmar, Chief Executive of the Prince's Foundation for the Built Environment and Chairman of the Board of Directors of the Congress for the New Urbanism, pointed out that the densest part of London functions satisfactorily at heights of four to six stories.

However, Andrés Duany argued that "too many cities would simply not qualify" with a stringent height standard, Peter Calthorpe threated to quit CNU if tall buildings were rejected, and Elizabeth Plater-Zyberk concluded "that's a sword that may not be worth falling on."

Tags: Urban Planning Urban Design Walkable Skyscrapers New Urbanism

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Direct Voter Control of Comprehensive Plans Fails

The initiative for Floridians to get to vote on major amendments to Comprehensive Plans is temporarily dead. The initiative required 611,009 valid signatures to get on the ballot. Florida Hometown Democracy organizers were pretty sure that they had handed in 814,000 signatures, but this is Florida, where counting of votes is not as straightforward as elsewhere. The state has counted only 552,703 signatures before the deadline.

The initiative would have meant if developers wanted to build in a protected area they would have to convince not just a few local officials, they would have to convince the voters. Business groups got pretty creative in stopping this initiative. They got a new law passed that makes it easier for signatures that were already counted to be removed, and they got the law to apply retroactively. They told people the law would increase their taxes and utility bills and let Big Developers destroy Florida's scenic beauty. They set up a competing similar-sounding but toothless initiative so that people would think they had already signed.

Three weeks before the January 31 deadline, floridians found out that the petition counting machines had been giving wrong numbers and the actual number of valid signatures would be changed downward as a result. Individual counties are responsible for counting signatures, and many couldn't keep up with the volume before the deadline, particularly because for the first time in history the Florida primaries were moved to January 29. Counties were told by the state that the primaries had priority for staff time, not counting signatures. In the strange Florida system, if the counties don't get around to counting it in time, the signature is not counted. In certain counties with a lot of signatures, the poor dears simply didn't have time to count them all. Coincidentally, those overworked counties were the very ones where the business groups concentrated their efforts, slowing down the processing.

The business groups outspent the environmental groups about 4 to 1. The decoy petition also did not get the required number of signatures. The signatures are still valid for the next election, two years from now. Keep watching.

Tags: Florida Democracy Environment Urban Planning

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TOD Mindset Moving Away From Pedestrian-friendly Focus

An article in ArchNewsNow makes some very odd and scary predictions about the future of Transit-Oriented Development (TOD).

The article talks about a mixed-use condo project in Clayton, Missouri, just west of St. Louis. As the picture (DeStefano + Partners) shows, the project is dominated by a 26-story condominium tower, with a multi-level parking garage and retail. Is this pedestrian-friendly? It looks significantly auto-oriented to me. The picture hides the highway and surface parking lots that surround the site. Environmentally sound? My paper on calculating the optimal housing mix and density for TOD gives some numerical background to why I agree with the Congress for New Urbanism that a diversity of housing forms is key, something that the current LEED-ND/Neighborhood Development pilot program does not sufficiently capture.

But the article then apparently relays this prediction by the project designer:

Current trends in TOD are expanding to include more flexible concepts. Transit-Adjacent Developments (TAD) - including Lindbergh City Center in Atlanta - are adjacent to transit systems, but step away from traditional TOD mindsets like making public spaces the focus of building orientation and neighborhood activity; creating pedestrian-friendly street networks that directly connect local destinations; and providing a mix of housing types and densities.

Tags: Urban Planning Urban Design Walkable LEED LEED-ND

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Land Use Responsible for Biofuel Carbon Debt

A new study by the Nature Conservancy and the University of Minnesota concludes that biofuels by and large emit more GHGs than the fossil fuels they replace.

This conclusion comes mostly from examining land use factors. Since additional land is required to grow crops for fuel in addition to the current food and cash crops, the conversion of land from its previous use to the new use should be considered. Among major biofuel crops are corn and sugar cane for ethanol in the US and Brazil, and oil palms for palm oil in Southeast asia. These lands are converted from rain forests, bogs, and other agricultural land whose production is also displaced. For instance, rotation of corn and soybeans is good for the soil, but the demand for ethanol has increased the price of corn, displacing the soybean crop. And so on.

The standard calculation for corn ethanol carbon balance used to be negative, that is to say it required more energy for tractors, fertilizers, heating and so forth than it produced in ethanol, until a more complex calculation started taking into account new technology and the byproducts - the animal feed that can be made from used corn mash and stalks. Do people use the new technology, do they feed the byproducts to cows and would they do that if the production of ethanol hadn't increased the price of the usual animal feed? The calculation was pretty marginal to begin with. To me the conclusion to be drawn from the ethanol calculation is that it is easier to reduce GHG emissions by eating less meat than by using biofuels and hoping that high meat consumption makes the figures add up properly.

This is now a game of tennis, alternating between more and more complex calculations taking into account more and more factors, each new calculation giving a result that is the opposite of the previous one. Which one can you trust? Of course the Nature Conservancy is biased in favour of nature. The Renewable Fuels Association calls this new calculation a simplistic view of land use but does not offer offer any numbers except to say "Tar sands, by comparison, release some 300 percent more greenhouse gas emissions than traditional petroleum recovery." This presumably means that they may emit more than fossil fuels but fossil fuels will catch up with them. They also say deforestation is not caused by a policy decision to produce liquid biofuels, but by food production. Hmmm, so they're saying if you want to save the rain forests and the earth's climate, don't stop driving cars, stop eating food instead.

It's an odd argument, especially when accusing a serious research project of being simplistic.

Tags: biofuel ethanol Greenhouse Gas Energy Environment

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