Authors: Tom Vanderbilt
was at work: The “availability heuristic” is credited to Daniel Kahneman and Amos Tversky. (
Heuristic
is a sophisticated-sounding word that really just means “mental shortcut.”) When people are asked to imagine how often something happens, they tend to overestimate the probability of things that can be more easily recalled from memory—that is, that are “available”—or that loom more vividly in the imagination.
mixed conclusions on this: See, for example, R. G. Golledge, K. L. Lovelace, D. R. Montello, and C. M. Self, “Sex-Related Differences and Similarities in Geographic and Environmental Spatial Abilities,”
Annals of the Association of American Geographers,
vol. 89 (1999), pp. 515–34.
as the distance did: A. J. Velkey, C. Laboda, S. Parada, M. L. McNeil, and R. Otts, “Sex Differences in the Estimation of Foot Travel Time,” paper presented at the annual meeting of the Eastern Psychological Association, Boston, March 2002. One factor that might lead women to overestimate distances is that, as previous studies have shown, distance estimations tend to be skewed in unpleasant or stressful surroundings. Women may not feel safe in large parking lots, which may help distort the sensation of how close or far a potential parking space is. See Sigrid Schmitz, “Gender Differences in Acquisition of Environmental Knowledge Related to Wayfinding Behavior, Spatial Anxiety and Self-Estimated Environmental Competencies,”
Sex Roles: A Journal of Research,
July 1999.
“optimal foraging”: For a good introduction to optimal foraging, see T. Schoener, “A Brief History of Optimal Foraging Ecology,” in
Foraging Behavior,
ed. A. C. Kamil, J. R. Krebs, and H. R. Pulliam (New York: Plenum Press, 1987), pp. 5–67. See also Jeffrey A. Kurland and Stephen J. Beckerman, “Optimal Foraging and Hominid Evolution: Labor and Reciprocity,”
American Anthropologist,
vol. 87, no. 1 (March 1985), pp. 73–93.
the effort of looking: This example is given in an interesting paper by Elizabeth Newell, a biologist at Hobart and William Smith Colleges, titled “The Energetics of Bee Foraging.” Retrieved from
http://www.life.umd.edu/Faculty/inouye/Pollination%20Exercises/Beth’s.htm
.
is the better option: Esa Ranta, Hannu Rita, and Kai Lindstrom, “Competition Versus Cooperation: Success of Individuals Foraging Alone and in Groups,”
American Naturalist,
vol. 142, no. 1 (July 1993), pp. 42–58.
spot to a destination: Mark Schlueb, “To Get to Game or Show, Parking May Be Tricky,”
Orlando Sentinel,
December 1, 2006.
destination is in sight: See Daniel R. Montello, “The Perception and Cognition of Environmental Distance: Direct Sources of Information,” in
Spatial Information Theory: A Theoretical Basis for GIS
(Berlin: Springer, 1997), pp. 297–311, and Lorin J. Staplin and Edward K. Sadalla, “Distance Cognition in Urban Environments,”
Professional Geographer,
vol. 33 (1981), pp. 302–10.
is “good enough”: See Herbert Simon,
Administrative Behavior,
4th ed. (New York: Free Press, 1997).
of their time parked: Donald Shoup,
The High Cost of Free Parking
(Chicago: American Planning Association, 2005), p. 6.
subsidized parking spots: Bruce Schaller, “Free Parking, Congested Streets,” March 1, 2007; available at
http://www.schallerconsult.com/pub/index.htm
.
“as has cycle parking space”: City of Copenhagen,
Traffic and Environmental Plan 2004,
p. 16.
“that will avoid shortages”: Shoup,
The High Cost of Free Parking,
p. 303.
metered street spots: Donald C. Shoup, “Cruising for Parking,”
Transport Policy,
vol. 13 (2006), pp. 479–86.
to thirteen minutes: Shoup,
The High Cost of Free Parking,
p. 279.
“vehicle per block was enough”: William Whyte,
City
(New York: Doubleday, 1988), p. 72.
all urban traffic collisions: See Paul C. Box, “Curb Parking Findings Revisited,”
Transportation Research Circular 501
(Washington, D.C.: Transportation Research Board, 2000).
8 miles per hour: This estimate, for streets with both parking and trees, comes from Dan Burden, “22 Benefits of Street Trees,” Glatting Jackson/Walkable Communities, Summer 2006.
shiny black sealcoat: See Peter C. Van Metre, Barbara J. Mahler, Mateo Scoggins, and Pixie A. Hamilton, “Parking Lot Sealcoat: A Major Source of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban and Suburban Environments,”
Fact Sheet 2005–3147
(Austin: U.S. Geological Survey, January 2006). Not surprisingly, the authors report that PAHs seem to be on the rise: “USGS findings show that concentrations of total PAHs in the majority of lakes and reservoirs in urban and suburban areas across the nation increased significantly from 1970 to 2001. The increases were greatest in lakes with rapidly urbanizing watersheds (urban sprawl); for example, over the last 10 years, the concentrations of PAHs in Lake in the Hills (suburban Chicago, Illinois) increased tenfold as the watershed was rapidly developed.”
three to one:
Douglas M. Main, “Parking Spaces Outnumber Drivers 3-to-1, Drive Pollution and Warming,” Purdue University News Service, September 11, 2007.
Chapter Six: Why More Roads Lead to More Traffic
during the shutdown: See Jon D. Haveman and David Hummels,
California’s Global Gateway: Trends and Issues
(San Francisco: Public Policy Institute of California, 2004), p. 62.
“all right by Friday”: See Richard Clegg, “It’ll Be Alright by Friday: Traffic Response to Capacity Reduction,” Department of Mathematics, University of York.
“based on those changes”: This equilibrium effect seems to happen even in extreme cases, like the 2005 transit strike in New York City. Suddenly, private vehicles, the only way to get into the city, needed to carry at least four passengers to enter during the peak hours of five a.m. to eleven a.m. The world was basically turned upside down. On the first day of the strike, the number of vehicles entering the Central Business District was down 24 percent. People were no doubt confused, unsure of what traffic would be like, or hoping for a quick end to the strike. By the second day, 21 percent fewer vehicles than normal entered. People began testing the waters or could not stay home from work any longer. And on the third day, the number was down to 13 percent fewer vehicles. The strike ended that day, so there is no way to know if traffic would have returned to normal; but clearly, people were adapting, either coming in much earlier (traffic levels at four a.m. tripled) or later than normal, or suddenly becoming believers in car pools. The numbers come from “2005 Transit Strike: Summary Report,” New York City Department of Transportation, February 2006.
“for other lines”: This line was quoted in the PBS documentary
New York Underground
(
American Experience
).
like population growth: See Lewis M. Fulton, Robert B. Noland, Daniel J. Meszler, and John V. Thomas, “A Statistical Analysis of Induced Travel Effects in the U.S. Mid-Atlantic Region,”
Journal of Transportation and Statistics,
vol. 3, no. 1 (2000), pp. 1–14. A study in California found that a 1 percent increase in lane-miles creates an immediate increase in vehicle-miles traveled of 0. 2 percent. See Mark Hansen and Huang Yuanlin, “Road Supply and Traffic in California Urban Areas,”
Transportation Research A,
vol. 31 (1997), pp. 205–18. Robert B. Noland, a scientist at Imperial College London, has compiled an extensive bibliography of “induced demand” research; it’s available at
http://www.vtpi.org/induced_bib.htm
.
on the affected roads: See S. Cairns, S. Atkins, and P. Goodwin, “Disappearing Traffic? The Story So Far,”
Municipal Engineer,
vol. 151, no. 1 (March 2002), pp. 13–22. There was an interesting example of this phenomenon in New York City. When Christo’s
The Gates
was on display in New York’s Central Park and the roads that crisscross the park were closed to traffic, the city’s transportation department did find local streets more crowded, for the short time that the art was installed. But commute
speeds
were not hugely affected, largely, according to the DOT, because of special preparations. It is not difficult to imagine that the DOT could also make preparations for closing the park drive to vehicles permanently.
The Gates
was a huge draw, of course, so we need to factor in how much of the new traffic volume was from people coming to see the art.
congestion itself as an evil: Asha Weinstein Agrawal, a professor of urban planning at San Jose State University, has shown, using Boston as a case study, that the notion of exactly
why
congestion is bad is quite fluid, often depending on the needs of a political class. At the turn of the century, safety and personal travel time were often invoked as reasons to cure what the mayor called the “evils of congestion,” but by the 1920s, arguments usually tended to focus on the negative economic consequences of congestion, including a rise in the cost of living. Why? “The growing emphasis on congestion and the cost of living was most likely a political effort to convince the larger population that congestion-generated delay was a problem for them, too, even if they didn’t directly experience it as auto drivers,” she writes. “Once the subway eliminated the congestion-induced delay experienced by people traveling downtown on the streetcars, proponents of expensive and controversial congestion relief projects like the loop highway needed a new argument to convince the general public that they should support these policies, and the cost-of-living argument filled that role.” See Agrawal, “Congestion as a Cultural Construct: The ‘Congestion Evil’ in Boston in the 1890s and 1920s,”
Journal of Transport History,
vol. 27, no. 2 (September 2006), pp. 97–113.
“less crowded roads elsewhere”: Brian D. Taylor, “Rethinking Traffic Congestion,”
Access
(October, 2002), pp 8–16.
boosts productivity: Timothy F. Harris and Yannis M. Ioannides, “Productivity and Metropolitan Density,” Dept. of Economics, Tufts University, 2000,
http://ase.tufts.edu/econ/papers/200016.pdf
.
the hassles of congestion: Helena Oliviero, “Looking for Love in All the Close Places,”
Atlanta Journal Constitution,
October 15, 2002, and Katherine Shaver, “On Congested Roads, Love Runs Out of Gas,”
Washington Post,
June 3, 2002. These citations come from Ted Balaker,
Why Mobility Matters to Personal Life,
Policy Brief 62 (Washington, D.C.: Reason Foundation, July 2007).
Brookings Institution: See Anthony Downs,
Still Stuck in Traffic: Coping with Peak-Hour Traffic Congestion
(Washington, D.C.: Brookings Institution, 2004), p. 27.
close to $12 billion: This, and the $108 billion figure, come from Gabriel Roth, ed.,
Street Smart: Competition, Entrepreneurship, and the Future of Roads
(New Brunswick: Transaction Publishers, 2006), p. 7.
since Juvenal’s Rome: Asha Weinstein Agrawal argues that “the essential challenges of traffic congestion are fundamental to urban life, and therefore unlikely to disappear as long as people choose to base their social and economic institutions around the free and frequent interaction that becomes possible in cities and towns.” From “Congestion as a Cultural Construct.”
Dietrich Braess: Dietrich Braess (translated from the orginal German by A. Nagurney and T. Wakolbinger), “On a Paradox of Traffic Planning,”
Transportation Science,
vol. 39 (2005), pp. 446–50.
J. G. Wardrop: J. G. Wardrop, “Some Theoretical Aspects of Road Traffic Research,”
Proceedings of the Institute of Civil Engineers, Part II
(1952) pp. 325–78.
total travel time would
drop:
My example for traffic equilibrium and the Braess paradox was inspired by an article by Brian Hayes, “Coping with Selfishness,”
American Scientist,
November 2005.
really makes the head spin: When I asked Anna Nagurney, an expert in networks at the University of Massachusetts at Amherst who helped translate Braess’s paper into English, if Braess’s paradox actually exists in the real world, she said that while he was treating the problem mathematically, there is no reason it could not; she also noted that “Braess even lucked out by picking that [traffic] demand because it lies within a range where the Braess paradox will occur.”
“selfish routing”: Tim Roughgarden,
Selfish Routing and the Price of Anarchy
(Cambridge, Mass.: MIT Press, 2005).
more than $2,000: Aaron Edlin and Pinar Karaca-Mandic, “The Accident Externality from Driving,” U.C. Berkeley Public Law Research Paper No. 130; available at
http://ssrn.com/abstract=424244
.
2.3 cents per mile: The original estimate comes from Ken Small and Camilla Kazimi, “On the Costs of Air Pollution from Motor Vehicles,”
Journal of Transport Economics and Policy,
January 1995, pp. 7–32. The updating to 2005 dollars is from Ian Parry, Margaret Walls, and Winston Harrington, “Automobile Externalities and Policies,” Resources for the Future Discussion Paper No. 06-26, January 2007.
$10 billion per year: M. A. Delucchi and S.-L. Hsu, “The External Damage Cost of Noise from Motor Vehicles,”
Journal of Transportation and Statistics,
vol. 1, no. 3 (October 1998), pp. 1–24.
rates and speeds: William T. Hughes Jr. and C. F. Sirmans, “Traffic Externalities and Single-Family House Prices,”
Journal of Regional Science,
vol. 32, no. 4 (1992), pp. 487–500.
prices often rise: After Clematis Street in West Palm Beach, Florida, was narrowed and retrofitted with bulb-outs and other traffic-calming measures, property values doubled. See “The Economic Benefits of Walkable Communities,” report published by the Local Government Commission Center for Livable Communities, Sacramento, California.
and coronary problems: There is a huge literature examining the potential links between traffic and health; for example, see A. J. Venn, S. A. Lewis, M. Cooper, et al., “Living Near a Main Road and the Risk of Wheezing Illness in Children,”
American Journal of Respiratory and Critical Care Medicine,
vol. 164 (2001), pp. 2177–80. The fact that houses tend to be cheaper near heavy traffic introduces epidemiological uncertainty, however, because in general the lives of people near the road are not the same, in socioeconomic terms, as those of people living on estates well back from the road. Is it living near the road that gives a person health problems, or are the problems due to something else about the lives of people who dwell near the road?