No Light Rail in Vancouver!

The Data Problem: Planners Can’t Get Enough

Jan 3

2007

I count architect Andres Duany as a friend who believes in New Urban design but is skeptical of coercive planning. But his book, Suburban Nation (co-written with Elizabeth Plater-Zyberk and Jeff Speck), advises that “The most effective plans are drawn with such precision that only the architectural detail is left to future designers.”

This is from a section on “Regional Government,” so Duany is clearly advising regional planners to dictate land uses to landowners throughout their regions. Yet it is simply impossible to imagine that planners could do this.

In his classic book on Houston, Land Use Without Zoning, the late Bernard Siegan observed that planners would have to consider “questions of compatibility, economic feasibility, property values, existing uses, adjoining and nearby uses, traffic, topography, utilities, schools, future growth, conservation, and environment.” Before developers invest millions of dollars in a piece of land, they typically spend thousands or tens of thousands of dollars doing a market analysis and feasibility study to find out what is the best use of that parcel.

Planners don’t have that kind of money to invest in every parcel in their city or region, yet the job they claim to do is even more formidable than the studies done by developers. Planners say they want to assess externalities, public goods, and all sorts of other things that developers don’t study because they don’t affect the profitability of the development.

How much data would you need to do a simple transportation plan for a modest city of 100,000 people? Consider how many trips you take per week, how many miles you travel, and how many different destinations you visit. Now multiply that by 100,000. Now add in the externalities that planners claim to account for: pollution, energy costs, safety, congestion. Don’t forget the externalities that planners don’t bother to account for, such as the added worker productivity that comes from increased mobility.

So how many pieces of data is that? Whatever the number, it is obviously overwhelming. And the data requirements for a land-use plan are even greater.

Of course, planners don’t even try to collect this much data. Instead, they rely on gross simplifications. Transportation planners look at all the people driving on a freeway at rush hour and say, “If we had a rail line parallel to this freeway, a lot of people would use it.” What they don’t see is that the cars on that freeway have tens of thousands of different origins and destinations, on a tiny number of which could be served by rail transit.

Meanwhile, Duany’s company has simplified land-use planning by placing all possible uses into a “transect” of six zones: natural, rural, suburban, general urban, urban center, and urban core. While these are slightly different from the traditional six zones of rural, rural residential, single family, multi-family, commercial, and industrial, either system fails to capture all of the potential variety of land uses. Where is exurban residential (perhaps missing because modern planners don’t believe it is legitimate)? Where are urban farms (ditto?)? And why should development follow this particular transect? Why not rural next to urban, suburban next to nature, nature next to an urban core?

The danger with such simplification is that it narrows options. Duany wants planners to leave nothing but the architectural detail to landowners. But he also wants them to fit all developments into just four zones (since natural and rural presumably won’t be developed). Doesn’t that mean that all developments will have to fit into just four different molds? I am sure Duany would say no, but planners have a way of simplifying even the simplifications proposed by the architects who inspire them.

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Reprinted from The Antiplanner