Traffic

by Tom Vanderbilt

  been in a crash): E. Lagarde, M. Chiron, and S. Lafont. “Traffic Ticket Fixing and Driving Behaviours in a Large French Working Population,” Journal of Epidemiology and Community Health, vol. 58 (2004), pp. 562–68.

  hundreds of traffic fatalities: Alexandre Dorozynski, “French Elections Can Kill,” British Medical Journal, November 3, 2001, p. 1021.

  The lesson is: At least one analysis posits that income equality is related in a linear fashion to traffic fatalities; e.g., in both poor, and, to a lesser extent, wealthy countries, the traffic fatality rate may be affected by the level of income equality. Perhaps not surprisingly, the Scandinavian countries, among the leaders in income equality, also rank near the top in traffic safety. See Nejat Anbarci, Monica Escaleras, and Charles Register, “Income, Income Inequality and the ‘Hidden Epidemic’ of Traffic Fatalities,” No. 5002, Working Papers from Department of Economics, College of Business, Florida Atlantic University. Retrieved from http://econpapers.repec.org/paper/falwpaper/05002.htm.

  and traffic fatalities: This relationship is argued in, among other sources, D. Treisman, “The Causes of Corruption: A Cross-National Study,” Journal of Public Economics, no. 76 (June 2000), pp. 399–457.

  income and traffic fatalities: See Nejat Anbarci, Monica Escaleras, Monica Register, and Charles A. Register, “Traffic Fatalities and Public Sector Corruption,” Kyklos, vol. 59, no. 3 (August 2006), pp. 327–44; available at http://ssrn.com/abstract=914243.

  of Europe’s road fatalities: See “Fools and Bad Roads,” Economist, March 22, 2007.

  rewards inefficient firms: For a good review of the various debates over corruption and growth, see P. Bardhan, “Corruption and Development: A Review of Issues,” Journal of Economic Literature, vol. 35 (September 1997), pp. 1320–46.

  beneath the acceptable “minimum”: See Daniel Kaufmann, “Corruption: The Facts,” Foreign Policy, no. 107 (Summer 1997), pp. 114–31.

  because of corruption: The most extreme case of this may be Lagos, the largest city in Nigeria and predicted to be among the world’s largest cities in the next decade. The average commuter in Lagos is said to face myriad challenges. These begin with the crumbling roads and infrastructure, which have scarcely been repaired since being erected in the oil boom of the 1970s; they themselves are a kind of symbol of the endemic corruption of Nigeria, where close to $400 billion in oil revenues were sequestered out of the country in a forty-year period. Other challenges include arbitrary fees charged at will by bus drivers and their quasi-official associates, the agberos, not to mention the numerous unofficial roadblocks, manned by gangs of unemployed “area boys,” that drivers must navigate. The multiple levels of corruption present in—and contributing to—Lagos’s epic “go-slows” were demonstrated in an astonishing story told by the journalist George Packer. While riding on the streets of Lagos, Packer’s driver was stopped by an agbero, who demanded money to help the driver negotiate another bribe, with the official traffic police. The traffic cop intervened, if only to collect the bribe—not doing so, it seemed, would actually make the police officer look as if he were derelict in his duty. See George Packer, “The Megacity: Decoding the Chaos of Lagos,” New Yorker, November 26, 2006. See also Adewale Ajayi, Nigerian Tribune, March 2, 2007; and Osise Dibosa, “Olubunmi Peters and Ferma,” This Day, June 12, 2007.

  take their place: Benjamin A. Olken and Patrick Barron, “The Simple Economics of Extortion: Evidence from Trucking in Aceh,” NBER Working Paper No. 13145, National Bureau of Economic Research, June 2007.

  “work repairing potholes”: Robert Guest, “The Road to Hell Is Unpaved,” Economist, December 19, 2002.

  “actual driving skill”: The Delhi driving-license experiment is detailed in Marianne Bertrand, Simeon Djankov, Rema Hanna, and Sendhil Mullainathan, “Does Corruption Produce Unsafe Drivers?” NBER Working Paper No. 12274, National Bureau of Economic Research, June 2006.

  “clarity of purpose”: This line comes from Pavan K. Varma, Being Indian (London: Penguin Books, 2005), p. 79.

  some 150,000 tickets: Raymond J. Fisman and Edward Miguel, “Cultures of Corruption: Evidence from Diplomatic Parking Tickets,” NBER Working Paper No. W12312 (June 2006). Retrieved at http://ssrn.com/abstract=910844.

  the city of London: Retrieved from Channel Four News Online, http://www.channel4.com/news/articles/society/environment/diplomatic+ccharge+bill+ tops+45m/569892.

  pays the charge: Nicola Woolcock, “Nations Unite to Join a Boycott of Congestion Charge,” Times (London), February 21, 2007.

  norms regarding them: This is why we can often see compliance with traffic laws differing even within a country. In Italy, corruption is more endemic in the south than the north, for reasons, as mentioned in an earlier note, having to do with varying degrees of civic culture. And so as the state seems to gradually wither away the farther south you go, so too does the traffic behavior come to have less to do with the law. In 2000, a national helmet law was passed for motorcyclists of any age. Afterward, usage rates in the north were reported as high as 95 percent. In the south, however, they were only as high as 70 percent, and as low as 50 percent. For corruption levels, see Alfredo del Monte and Erasmo Papagni, “The Determinants of Corruption in Italy: Regional Panel Data Analysis,” European Journal of Political Economy, vol. 23 (June 2007), pp. 379–96. For helmet-use rates, see F. Servadei, C. Begliomini, E. Gardini, M. Giustini, F. Taggi, and J. Kraus, “Effect of Italy’s Motorcycle Helmet Law on Traumatic Brain Injuries,” Injury Prevention, vol. 9, no. 3 (2003), pp. 257–60.

  casualties there will be: See D. Parker, J. T. Reason, A. S. R. Manstead, and S. G. Stradling, “Driving Errors, Driving Violations and Accident Involvement,” Ergonomics, vol. 38 (1995), pp. 1036–48.

  more women in government: Anand Swamy, Stephen Knack, Young Lee, and Omar Azfar, “Gender and Corruption,” Center for Development Economics, Department of Economics, Williams College, 2000.

  Chapter Nine: Why You Shouldn’t Drive with a Beer-Drinking Lawyer

  our brains as we drive: Research has shown that the various aspects of driving, everything from following a traffic rule (e.g., specifying a one-way street) to navigating a set of directions to anticipating the actions of other drivers, seem to trigger discrete activity in a variety of brain regions and networks. Researchers at University College London, for example, have monitored drivers as they “drove” the detailed recreation of London found in the popular video game The Getaway. See H. J. Spiers and E. A. Maguire, “Neural Substrates of Driving Behaviour,” NeuroImage, vol. 36 (2007), pp. 245–55.

  fifty thousand times a year: P. G. Martin and A. L. Burgett, “Rear-End Collision Events: Characterization of Impending Crashes,” Proceedings of the First Human-Centered Transportation Simulation Conference (Iowa City: University of Iowa, 2000).

  walks away alive: See Jack Stuster, “The Unsafe Driving Acts of Motorists in the Vicinity of Large Trucks,” U.S. Department of Transportation, Federal Highway Administration, Office of Motor Carriers and Highway Safety, February 1999.

  should probably fear: See L. J. Armony, D. Servan-Schreiber, J. D. Cohen, and J. E. LeDoux, “An Anatomically-Constrained Neural Network Model of Fear Conditioning,” Behavioral Neurocience, vol. 109 (1995), pp. 246–56.

  dangerous nature of trucks: Opinion surveys of car drivers tend to find mostly negative opinions of truck drivers’ behavior. See, for example, Robert S. Moore, Stephen LeMay, Melissa L. Moore, Pearson Lidell, Brian Kinard, and David McMillen, “An Investigation of Motorists’ Perceptions of Trucks on the Highways,” Transportation Journal, January 5, 2001.

  responsibility in the crash: Daniel Blower, “The Relative Contribution of Truck Drivers and Passenger Vehicles to Truck-Passenger Vehicle Traffic Crashes,” report prepared for the U.S. Department of Transportation, Federal Highway Administration, Office of Motor Carriers, June 1998.

  is actually the case): This may be the “availability heuristic” at work again. Large trucks, in part because they are driven longer distanc
es and tend to be on the road at the same time as most motorists, seem to be more prevalent than they really are. A Canadian study found that while motorists believed that the number of trucks on the roads was rising, the number actually dropped during the period in question (while the number of cars grew). See Gordon G. Baldwin, “Too Many Trucks on the Road?” Transportation Division, Statistics Canada, Ottawa.

  “risk as analysis”: Paul Slovic, Melissa L. Finucane, Ellen Peters, and Donald G. MacGregor, “Risk as Analysis and Risk as Feelings: Some Thoughts About Affect, Reason, Risk, and Rationality,” Risk Analysis, vol. 24, no. 2 (2004), pp. 311–23.

  50 years of driving: Data retrieved on May 5, 2007, from http://hazmat.dot.gov/riskrngmt/riskcompare.htm.

  the lifetime probability: P. Slovic, B. Fischhoff, and S. Lichtenstein, “Accident Probabilities and Seat Belt Usage: A Psychological Perspective,” Accident Analysis & Prevention, vol. 13 (1978), pp. 281–85.

  “the danger of leaving home”: William H. Lucy, “Mortality Risk Associated with Leaving Home: Recognizing the Relevance of the Built Environment,” American Journal of Public Health, vol. 93, no. 9 (September 2003), pp. 1564–69.

  eleven times that: This figure was provided to me by Per Garder, a professor of civil and environmental engineering at the University of Maine. Using the required risk exposure levels as quoted by the Occupational Safety and Health Administration (in “Occupational Exposure to Asbestos,” Federal Register 59:40964-41161, 1994, and OSHA Preambles, “Blood Borne Pathogens,” 29 CFR 1910.1030, Federal Register 56:64004, 1991: 29206), Garder notes that the risk of dying over a lifetime in manufacturing and service employment, respectively, “must be less than 1. 8 and 1.0 deaths per 1,000 employees.” By those standards, Garder extrapolates if 1 person in a 1,000 were “allowed” to die in traffic over an average of 77 years of life, 1 person in 77,000 would thus be allowed to die in America this year in a traffic accident. Using America’s population of 300 million, 1 in 77,000 would be 3,896 people. But the fatality figure was over 11 times that. In other words, if traffic were an industry—whether heavy manufacturing or service—it would have been shut down a long time ago.

  every thirty-two minutes: Fatality statistics were taken from Traffic Safety Facts 2004 (Washington, D.C.: National Highway Traffic Safety Administration, 2005).

  3 out of every 1,000: Clifford Winston, Vikram Maheshri, and Fred Mannering, “An Exploration of the Offset Hypothesis Using Disaggregate Data: The Case of Airbags and Antilock Brakes,” Journal of Risk Uncertainty, vol. 32 (2006), pp. 83–99.

  raises the crash risk: M. G. Lenné, T. J. Triggs, and J. R. Redman, “Time of Day Variations in Driving Performance,” Accident Analysis & Prevention, vol. 29, no. 4 (1997), pp. 431–37, and G. Maycock, “Sleepiness and Driving: The Experience of U.K. Car Drivers,” Accident Analysis & Prevention, vol. 29, no. 4 (1997), pp. 453–62.

  day to be on the road: As David Klein and Julian Waller noted, the posting of holiday traffic fatalities presents several problems. “Although absolute numbers may serve a purpose in indicating the raw impact of highway crashes on the nation or on a community,” they write, “their use provides only a partial indication of magnitude and often a misleading indication of trends. First, fatality figures ignore the 1. 5 to 3 million annual non-fatal injuries—which may represent a social cost far higher than the 56,000 fatalities. Second, the ‘holiday death toll’ may give drivers an unjustified feeling of anxiety on holiday weekends and a false sense of security on weekdays if it persuades them that the holiday incidence is substantially higher than on weekdays.” From Klein and Waller, “Causation, Culpability and Deterrence in Highway Crashes,” prepared for the Department of Transportation, July 1970, p. 27.

  week before or after: C. M. Farmer and A. F. Williams. “Temporal Factors in Motor Vehicle Crash Deaths,” Injury Prevention, vol. 2 (2005), pp. 18–23.

  should be about $8,000: Steven D. Levitt and Jack Porter, “How Dangerous Are Drinking Drivers?,” Journal of Political Economy, vol. 109, no. 6 (2001), pp. 1198–1237. The authors rely on a clever statistical trick that does not require knowing the actual number of drinking and sober drivers on the road (a number that would be extremely hard to come by in any case) but, rather, uses an extrapolation taken from the relative proportion of sober and drunk drivers involved in two-car crashes. Levitt and Porter generate their relative risk numbers by looking at two-car crashes and “the relative frequency of accidents involving two drinking drivers, two sober drivers, or one of each.” This information, they argue, “is sufficient to separately identify both the relative likelihood of causing a fatal crash on the part of drunk and sober drivers and the fraction of drivers on the road who have been drinking.”

  doubling of the speed: H. C. Joksch, “Velocity Change and Fatality Risk in a Crash: A Rule of Thumb,” Accident Analysis & Prevention, vol. 25, no. 1 (1993), pp. 103–04.

  doing 30 miles per hour: Allan F. Williams, Sergey Y. Krychenko, and Richard A. Retting, “Characteristics of Speeders,” Journal of Safety Research, vol. 37 (2006), pp. 227–32.

  get into more crashes: See, for example, Williams, Kyrychenko, and Retting. “Characteristics of Speeders,” ibid.

  additional 5 kilometers per hour: See C. N. Kloeden, A. J. McLean, V. M. Moore, and G. Ponte, “Travelling Speed and the Risk of Crash Involve ment,” NHMRC Road Accident Research Unit, University of Adelaide, November 1997.

  “relatively high speed drivers”: David Solomon, Accidents on Main Rural Highways Related to Speed, Driver, and Vehicle (Washington, D.C.: U.S. Department of Commerce, Bureau of Public Roads, 1964).

  flow in smooth harmony: The speed-variance argument was most famously taken up by Charles Lave, “Speeding, Coordination, and the 55 MPH Limit,” American Economic Review, vol. 75, no. 5 (December 1985), pp. 1159–64. Interestingly, in a point that has not been emphasized by those later citing Lave, he writes: “Although I have found no statistically discernible effect from speed, per se, this does not necessarily imply that it is safe to raise the speed limit, for we do not know what effect a higher limit would have on the speed variance.” If the speed limit is 65 miles per hour but many people are driving 75, it does not necessarily follow that raising it to 75 miles per hour will reduce speed variance or make things safer. Do we want the drivers who feel comfortable at a lower level forced to go faster? Do we want Grandma and Grandpa driving 75 miles per hour?

  held by young males: T. Horberry, L. Hartley, K. Gobetti, F. Walker, B. Johnson, S. Gersbach, and J. Ludlow, “Speed Choice by Drivers: The Issue of Driving Too Slowly,” Ergonomics, vol. 47, no. 14 (November 2004), pp. 1561–70.

  at low speeds: For elaboration on this point, see Kloeden, McLean, Moore, and Ponte, “Travelling Speed,” op. cit.

  involved a stopped vehicle: Ronald K. Knipling, “IVHS Technologies Applied to Collision Avoidance: Perspectives on Six Target Crash Types and Countermeasures,” technical paper presented at the Safety and Human Factors session of 1993 IVHS America Annual Meeting, Washington, D.C., April 14–17, 1993.

  not hold for individuals: Gary A. Davis, “Is the Claim That ‘Variance Kills’ an Ecological Fallacy?,” Accident Analysis & Prevention, vol. 34 (2002), pp. 343–46. With the Solomon curve, Davis argues that one cannot determine the individual driver’s crash risk by looking at the whole. Solomon’s curve, maintains Davis, is a purely mathematical effect that says little about how the world works, “like saying an object is heavy because it weighs more.” Another problem with the Solomon curve is that it does not explain causes. If twenty cars slowing for traffic congestion—and thus going below the median speed—were struck by ten cars traveling at the median and ten cars traveling above the median, the resulting “curve” would indeed suggest that slower drivers were the most at risk of being in a crash. But looking at each crash individually, one would conclude that the faster-moving cars had actually been the source of the risk for the slower-moving cars. As an example of a ecological fallacy, the statistician David Freedman has co
mpared the income levels of U.S. states against the percentage of foreign-born residents in each. Doing this, one could make a statistically robust “correlation” that says foreign-born residents of the United States earn more than native-born residents, when actually the opposite is true. See David A. Freedman, “Ecological Inference and the Ecological Fallacy,” in International Encyclopedia of the Social & Behavioral Sciences, vol. 6, ed. N. J. Smelser and Paul B. Baltes (New York: Pergamom, 2001), pp. 4027–30.

  in the same direction: E. C. Cerrelli, “1996 Traffic Crashes, Injuries, and Fatalities—Preliminary Report,” Report No. DOT HS 808 543, National Highway Traffic Safety Administration, March 1997. I was alerted to this finding by an excellent report summarizing the various speed issues. See Jack Stuster and Zail Coffman (1998), Synthesis of Safety Research Related to Speed and Speed Limits, FHWA-RD-98-154 (Washington, D.C.: Federal Highway Administration, 1998).

  whose teams had lost: D. A. Redelmeier and C. L. Stewart, “Do Fatal Crashes Increase Following a Super Bowl Telecast?” Chance, vol. 18, no. 1 (2005), pp. 19–24.

  have been drinking: R. G. Smart, “Behavioral and Social Consequences Related to the Consumption of Different Beverage Types,” Journal of Studies on Alcohol, vol. 57 (1996), pp. 77–84.

  at .08 to .1 percent: R. P. Compton, R. D. Blomberg, H. Moskowitz, M. Burns, R. C. Peck, and D. Fiorentino, “Crash Risk of Alcohol Impaired Driving,” Proceedings of the 16th International Conference on Alcohol, Drugs and Traffic Safety, CD-ROM (Montreal, Société de l’Assurance Automobile du Québec, 2002).

  BAC of zero: R. F. Borkenstein, R. F. Crowther, R. P. Shumate, W. B. Ziel, and R. Zylman, “The Role of the Drinking Driver in Traffic Accidents,” Bloomington, Indiana, Department of Police Administration and Indiana University, 1964.