Jeff Speck, an urban planner, is coauthor (with Andres Duany and Elizabeth Plater-Zyberk) of Suburban Nation: The Rise of Sprawl and the Decline of the American Dream, a 2000 bestseller, and author of the just-published Walkable City: How Downtown Can Save America, One Step at a Time. We asked him to pose questions about cities, pedestrians, and cars.
1. A study of Portland, Oregon’s east side found that each street tree was responsible for almost $10,000 in increased real estate value. Extrapolating to the city as a whole, the authors found that the presence of healthy street trees likely adds $15.3 million to annual property tax revenues. The City of Portland spends $1.28 million a year on tree planting and maintenance, resulting in a payoff of 12 to one. Given this ratio, why do most cities invest so little in trees?
2. More than 16 million new households are expected to take shape between now and 2040. The economist Chris Leinberger calculates that 88 percent of them will be childless. This is a dramatic change from 1970, when almost half of all households included children. What does this trend say about the future of American cities and suburbs?
3. Thanks largely to the ways communities are designed today, less than 15 percent of schoolchildren now walk to school—compared with nearly 50 percent in the 1970s. Yet the number of 19-year-olds who have opted out of earn- ing driver’s licenses has almost tripled since the late ’70s, from eight percent to 23 percent.
Why is it that kids who grew up being driven are now choosing to drive less themselves?
4. Alan Durning, author of The Car and the City, analyzed the combined risk of dying from two causes—traffic crashes and crime—in Seattle, Portland, and Vancouver. He found that, on average, if you add the two factors together, you are 19 percent safer in the inner city than in the outer suburbs. Why do people move to the suburbs for the safety of their children?
5. A Chevy Tahoe Hybrid is rated at 21 miles per gallon; a conventionally powered Ford Fiesta gets 33 miles per gallon. Why is only the former allowed to use a “hybrids only” parking spot?
6. In Sweden, aggressive government subsidies have
led to the world’s highest per capita sales of “green” cars. Yet greenhouse gas emissions from Sweden’s transportation sector have, surprisingly, risen. Could it be that people feel so good about their clean cars that they are now driving enough addi- tional miles to undo the effects of increased efficiency?
7. Studies now prove that expanding road capacity does nothing to reduce traffic congestion because latent demand quickly absorbs the new supply. According to the historically prohighway Texas A&M Transportation Institute, “metro areas that invested heavily in road capacity expansion fared no better in easing congestion than metro areas that did not.” Why, then, do we keep trying to build our way out of congestion?
