Friday, September 20, 2013
The recently issued second edition of EPA’s Our Built and Natural Environments: A Technical Review of the Interactions Between Land Use, Transportation, and Environmental Quality, which I previously blogged about, has a lot of great information in it.
One piece of data that keeps me coming back--and scratching my head--is the table below (reproduced below my signature; click on image for full-sized chart), which compares 1950 population and land area to 2010 population and land area of major American cities. The chart then lists cities in descending order of the ratio of land area growth to population growth. So what city had the greatest land area gain compared to its population growth in the last six decades? Pittsburgh (ratio of land area growth to population growth=19.6), Boston (7.6), Milwaukee (6.6), Philadelphia (6.2), and Detroit (6.1). What cities had the lowest ratio of land area gain to population growth in the study? San Jose (.4), Los Angeles (.5), Riverside-San Bernardino (.6), Salt Lake City (.8), and San Diego (.8).
What to make of these numbers? When I first looked at the data, and starting at the top of the chart, it appeared that Pittsburgh was a city especially worthy of sprawl scorn; after all, its ratio of land area gain to population gain was just shy of 3 times the next city—Boston—on the list. However, by the time I got to the bottom of the list to the cities I expected to be laudatory smart-growth cities, I did not see what I expected. Are San Jose, Los Angeles, Riverside, Salt Lake City and San Diego what you think of when you think of compact development? No me.
What do these numbers indicate to you? I’d be curious of how readers respond to these numbers, either as to whether they have any real statistical significance or any anecdotal data on the ground about cities listed on the table.
Stephen R. Miller