Reason's Bob Poole on land use and transportation
It's been a long day and getting to be a late night, so just a quick pass-along tonight. From the July Surface Transportation Innovations newsletter
, with my comments afterward.
Land Use and Transportation: Are U.S. Cities Different?
What is it about America that makes European-type mass transit so difficult to do here? Is it just pig-headedness that people won’t use it and continue to drive alone, despite serious congestion? Or is there something fundamentally different that makes transit much less suitable in U.S. metro areas?
That’s the question posed by urban economist Alain Bertaud, a European who now lives and works in this country, loves urban life, and uses mass transit. I recently came across his remarkable paper “Clearing the Air in Atlanta: Transit and Smart Growth or Conventional Economics?” published in the Journal of Urban Economics in 2003 (No. 54) and available at http://alain-bertaud.com. While it uses Atlanta as a case in point, its assessment is largely applicable to most U.S. metro areas, especially those outside the Northeast.
In response to high levels of congestion and air pollution, Bertaud recounts, Atlanta’s MPO developed new long-range transportation plans focused on reducing VMT via a twin-pronged strategy of large-scale investment in transit and fostering land-use changes to encourage transit-oriented development. Bertaud takes a careful look at how much these policies might be able to accomplish. His conclusion is that Atlanta’s spatial structure is such that “it is a geometrical impossibility for Atlanta to increase its density to reach the threshold level which would allow an effective operation of transit.”
To fully appreciate Bertaud’s paper, you must download it and peruse the graphs and charts. Several compare the densities of U.S. cities with those of overseas cities like Marseilles, London, Paris, Rio, and Barcelona where transit is a significant fraction of urban trip-making. In particular, his graphs show how concentrated (in both population and jobs) are the central business districts of transit-oriented cities abroad, compared with typical American ones. I was especially amazed by his chart showing the built-up areas of Atlanta and Barcelona at the same scale; with comparable populations in 1990 (2.5 to 2.8 million), Atlanta covers 4,280 sq. km.—compared with just 162 sq. km. for Barcelona. To provide the same level of metro accessibility in Atlanta as exists in Barcelona would require Atlanta to add 3,400 km. of metro line and 2,800 more stations.
He also looks into what happened to Atlanta’s population and jobs growth during the decade of the 1990s. The vast majority of both occurred far from the “central business district”, mostly within a belt between 30 and 45 km. from downtown. The actual CBD lost 10,000 jobs during that decade.
Bertaud then looks at the potential of two hypothetical densification strategies, crunching some numbers to see what it would take to bring the Atlanta metro area to the density threshold levels necessary to make transit accessible to significant numbers of people. The first estimates the amount of built-up area needed to achieve a density of 30 persons per hectare, a threshold level cited in several studies. Given projected population growth over 20 years, the built-up areas could be no more than 1,555 sq. km.—two-thirds less than exists today. Since that is a non-starter, he then calculates what would happen if planners banned any further expansion of the existing built-up area, forcing all growth to be “in-fill.” After 20 years, that would produce a density of only 11 persons per hectare, less than half the current density of Los Angeles and only one-third of the threshold level. Hence, he concludes, while New Urbanist neighborhoods may be nice things, such designs “will have no measurable impact on the spatial structure of Atlanta and therefore no impact on pollution and congestion.”
What should work, instead, is charging for highway use, combined with flexible mini-bus service. Transit would be recognized as a niche market for the transit dependent—a very different vision from today’s focus on moving heaven and hell to attract “choice riders.” Technology would solve the air pollution problem, via stringent tailpipe emission standards, fleet turnover, and the increasing use of alternative propulsion.
Tory comments: Atlanta and Houston are essentially equivalent for the purposes of this note. I agree with most of this - the no measurable impact on spatial structure, pollution, or congestion, and the last paragraph solutions - but he does overlook one thing: that density can build up in concentrated areas near transit stops ("transit-oriented development") rather than spread over the metro. While the overall metro is essentially unaffectable, a lot of people who do want to live the New Urbanist lifestyle could live along transit lines and walk or use transit for many of their trips. There's a big question how many people want to live that way, but there clearly is unmet demand in most cities today, and we should make efforts to offer it to those who want it. But it is good to get past the fantasy that most American cities can ever fully emulate the European model (and, as a matter of fact, many European cities are moving away from their own model and building ever-larger car-based suburbs).