Growth and density: Let's do the numbers

An expert on urban demographics argues that there's not a lot Seattle can do to change growth patterns and prevent sprawl. But some modest accommodations can be made.
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Seattle's Capitol Hill, with Bellevue and the Cascade Mountains in the background. (Chuck Taylor)

An expert on urban demographics argues that there's not a lot Seattle can do to change growth patterns and prevent sprawl. But some modest accommodations can be made.

Solutions seemingly abound for three key problems in Seattle: rapid growth, traffic congestion, and the need for more (or less) density. Time for a dose of reality, neighbors. There are no "solutions." Here as in Iraq, there are only some tolerable accommodations. Let me start with growth. First, there's no real way to stop or slow it, because the U.S. Supreme Court ruled (when Los Angeles tried to stop the influx of Okies in the 1930s) that the Constitution protects freedom of movement. We might stop stimulating economic development, but that will have little effect. If a place looks attractive to people and businesses, they can and will come. But the growth is not flooding back into the central cities. Ninety percent of metropolitan growth is in the suburbs, which are gaining higher shares of less affluent families, singles, couples, and empty-nesters. Seattle Mayor Greg Nickels' goal of 350,000 more people in Seattle is not supported by demography or economic demand. Given this growth, what can we do about housing price inflation and other affordability issues? The key factor is supply and demand economics. Metropolitan Seattle has compounded the constraints on land caused by our geography by implementing urban growth boundaries. If we had not used urban growth boaundaries as part of growth management, housing supply would be somewhat greater and prices still fairly expensive but perhaps 15 percent lower (comparing Seattle to less restrictive but also professional cities such as Denver, Minneapolis, and Dallas). There are other factors besides the shortage of developable land driving up Seattle prices. Seattle is a high-cost metropolis in such factors as labor, materials, and levels of public services and amenities. Washington's nation-leading level of minimum wage is a good thing, but it does help drive up housing prices. Also, there are lots of people in Seattle (as in Boston, Washington, San Francisco, San Diego, and Los Angeles) willing and able to pay a premium for high-quality housing, and many of these people migrate here from other areas with even higher prices. Finally, local zoning and permitting tend to favor higher-revenue-generating housing and business. So what could we do to put some downward pressure on housing prices? I have long advocated relaxing or abolishing urban growth boundaries and substituting subdivision performance standards that require moderately high densities. Another approach would be direct public construction of "social housing," as is done in Europe on a large scale. Requirements for inclusion of more affordable units in private developments, the current preferred strategy, are too insignificant to affect housing supply and prices. Some jurisdictions, normally pretty long commutes from the central city, may accept fairly high shares of lower-cost housing, as is happening in California's Central Valley, and this can make an important contribution. Doubling up, often sub rosa, in the existing housing supply is the dominant "solution" to unaffordable housing in Los Angeles and San Diego, to give two examples. Especially for families, who prefer a patch of yard and homes rather than apartments, this is a reasonable course to follow. This informal utilization of existing housing stock, rather than more disruptive levels of apartment construction, may be the best way to minimize the pace of urban fringe expansion. It can keep families in the inner parts of the metropolis. If families are driven from the core, they will go to the edges and beyond. Now, let's look dispassionately at the heated debate over density. Density is driven by demand and affluence, and it affects cities all over the world and all through history. Governments, through fiat or planning, have long tinkered with densities, but in the long run, the preferences of households and of businesses rule. Nor is there a level of density that is somehow "better." We have areas of very high densities, of low densities, and of all levels in between, simply because there is sufficient demand for those densities, driven by differing needs and preferences. But, you counter, what about the costs of sprawl and lamentable suburban monotony? Studies of the costs of infrastructure and public services show only slight variation with density, with moderately higher costs at very low densities (under 1,500 people per square mile) and at very high densities (over 100,000 per square mile). Lower utilization drives up costs at the low density end, while high costs of construction and maintenance affect highly dense areas. The most effective densities are in the middle range, 5,000 to 15,000 people per square mile, which happens to be where probably more than 90 percent of urban dwellers live. Impacts of cities on the environment are mostly a function of the sheer population size of the metropolis, not its density or urban form. What about the impacts of sprawl or compactness on quality of life? There turn out to be no meaningful differences in quality of family life, health or exercise, diet, intellectual curiosity, and neighborhood sociability all across the spectrum from rural farm life to urban high rises, if you control for age, family status, education, job location, and so forth. There may be a slight edge for overall urban livability in the traditional urban family neighborhoods of 5,000 to 12,000 per square mile. That would describe the actual urban and suburban neighborhoods of the Seattle region, with apartments mainly along arterials and single-family houses in between. This is not to deny that political conflict, often of an intense sort, happens as cities grow and market forces move urban development both up and out. At the urban edge, those enjoying a quasi-rural life will resist the tide of urbanity, and environmentalists will fight the conversion of resource land to urban use. In older, developed areas, the growing share of the population that is childless, single, or with empty nests creates a market for apartment rentals and condominiums, changing older neighborhoods and driving up prices. Lastly, there is the conflict caused by gentrification, the replacement of the less affluent by the more affluent. This is not usually redevelopment or even densification, since most gentrifiers want older single-family houses. Sadly for the non-rich, the gentrifiers arrive with a potent combination of higher education, professional occupations, and financial assets. The only hope for the average household being pushed out is to live in areas not targeted by the gentrifiers, or to meet their bids by combining numbers.


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