Traffic (45 page)

involved lane changes: Basav Sen, John D. Smith, and Wassim G. Najm, “Analysis of Lane Change Crashes,” DOT-VNTSC-NHTSA-02-03, National Highway Traffic Safety Administration, March 2003.

how many were discretionary?: One study that compared crashes to traffic volume (obtained via loop-inductor data) found that most lane-change crashes occurred, perhaps not surprisingly, when the variability of highway speeds across lanes was highest—in other words, the time when most people would find it advantageous to change lanes. See Thomas F. Golob, Wilfred W. Recker, and Veronica M. Alvarez, “Freeway Safety as a Function of Traffic Flow,”
Accident Analysis & Prevention,
vol. 36 (2004), pp. 933–46.

decisions we make while driving: At Cooper University Hospital in New Jersey, for example, doctors estimate that 60 percent of the trauma intensive care unit patients are the victims of car crashes; see Geoff Mulvihill, “In Corzine’s Hospital Unit, Handling Terrible Accidents Routine,”
Newsday,
April 23, 2007.

work zones: The work-zone fatality statistic comes from the U.S. Federal Highway Administration (
http://safety.fhwa.dot.gov/wz/wz_facts.htm
).

“merging difficulties”: From
Understanding Road Rage: Implementation Plan for Promising Mitigation Measures,
by Carol H. Walters and Scott A. Cooner (Texas Transportation Institute, November 2001).

lane that will close: Information on work-zone merge strategies was drawn from a number of useful sources, including “Dynamic Late Merge Control Concept for Work Zones on Rural Freeways,” by Patrick T. McCoy and Geza Pesti, Department of Civil Engineering, University of Nebraska.

smoothly through the work zone: The TRL data comes from a report by G. A. Coe, I. J. Burrow, and J. E. Collins, “Trials of ‘Merge in Turn’ Signs at Major Roadworks.” Unpublished project report, PR/TT/043/95, N207, October 30, 1997.

exactly where to merge: For a sample discussion of U.K. merging ambiguity, see
http://www.pistonheads.com/gassing/topic.asp?f=154&h=&t=256729
Retrieved on December 1, 2007.

which is also safer: See Federal Highway Administration, U.S. Department of Transportation, “Methods and Procedures to Reduce Motorist Delays in European Work Zones,” FHWA-PL-00-001, October 2000.

One important caveat: Another simulation study showed that the Late Merge strategy was more effective when two lanes narrowed to one than when three narrowed to two. According to one report, “A possible explanation may be evident in the way vehicles appeared to be behaving in the simulations. When simulation animations of the 3-to-2 lane configurations of the late merge control were viewed, it appeared that vehicles driving in the middle lane would move to the far left lane to avoid merging from the closing lane. This interaction slowed vehicles in the far left lane enough that throughput may have been significantly reduced.”
Evaluation of the Late Merge Workzone Traffic Control Strategy,
by Andrew G. Beacher, Michael D. Fontaine, and Nicholas J. Garber. Virginia Transportation Research Council, August 2004, VTRC 05—R6.

summer of 2003: The Minnesota Dynamic Late Merge information was drawn from two reports, “Dynamic Late Merge System Evaluation: Initial Deployment on I-10,” prepared by URS for the Minnesota Department of Transportation,” and a follow-up study, “Evaluation of 2004 Dynamic Late Merge System for the Minnesota Department of Transportation,” also prepared by URS.

blocked by trucks: Garber, in a telephone conversation, also noted the particular tendency of trucks to perform blocking maneuvers. He found that Late Merge worked best when the total volume of heavy vehicles in the traffic stream was less than 20 percent.

Chapter Two: You’re Not as Good a Driver as You Think You Are

fifteen hundred “subskills”: This estimate comes from A. J. McKnight and B. Adams,
Driver Education Task Analysis,
vol. 1,
Task Descriptions,
Washington D.C.: National Highway Traffic Safety Administration, 1970.

twenty per mile: Leslie George Norman, “Road Traffic Accidents: Epidemiology, Control and Prevention” (World Health Organization, Public Health Papers no. 12, 1962), p. 51.

440 words, per minute: This figure comes from William Ewald,
Street Graphics
(Washington, D.C.: American Society of Landscape Architects Foundation), p. 32.

“avoiding obstacles”: See
Urban Challenge Rules
(Arlington, Va.: Defense Advanced Research Projects Agency, July 10, 2007).

in the future: The cognitive scientist Donald D. Hoffman points out that an average traffic scene of a tree-lined street with cars creates a multitude of problems for computer intelligence, as analysis by researcher Scott Richman has revealed. Hoffman notes, “Several problems that Richman faced are evident from this picture: clutter, trees moving in the wind, shadows dancing on the road, cars in front hiding cars behind. A sophisticated analysis of motion, using several frames of motion at once, allows Richman’s system to distinguish the motion of cars from that of trees and shadows…. [Richman’s] system can trackcars through shadows, a feat that is trivial for our visual intelligence but, heretofore, quite difficult for computer vision systems. It’s easy to underestimate our sophistication at constructing visual motion. That is, until we try to duplicate that sophistication on a computer. Then it seems impossible to overestimate it.” From Donald D. Hoffman,
Visual Intelligence
(New York: W. W. Nortion, 1998), p. 170.

“caution for the caution”: See, for example, Don Leavitt, “Insights at the Intersection,”
Traffic Management and Engineering,
October 2003.

sooner
than necessary: H. Kölla, M. Badera, and K. W. Axhausen, “Driver Behavior During Flashing Green Before Amber: A Comparative Study,”
Accident Analysis & Prevention,
vol. 36, no. 2 (March 2004), pp. 273–80.

without the flashing green: D. Mahalel and D. M. Zaidel, “Safety Evaluation of a Flashing Green Light in a Traffic Signal,”
Traffic Engineering and Control,
vol. 26, no. 2 (1985), pp. 79–81.

chances to crash: This point is made in L. Staplin, K. W. Gish, L. E. Decina, K. H. Lococo, D. L. Harkey, M. S. Tarawneh, R. Lyles, D. Mace, and P. Garvey in
Synthesis of Human Factors Research on Older Drivers and Highway Safety,
vol. 2, Publication No. FHWA-RD-97-095, 1997. Available at
http://www.fhwa.dot.gov/tfhrc/safety/pubs/97094/97094.htm
.

“bump itself up the queue”: One might think that robot drivers would be free from the complicated psychological dynamics that trouble humans at intersections; yet, perhaps like humans, it all depends on how they are wired. “Robots can be more aggressive or more conservative,” Montemerlo told me. You might, for example, “program your robot to always ignore the queuing order and always go first, to be a pushy robot.” But whether or not this strategy works depends on how the other robots have been programmed. Four pushy robots at a four-way stop could get ugly quickly.

“They slow everyone down”: This recalls a comment from T. C. Willet’s
Criminal on the Road: A Study of Serious Motoring Offences and Those Who Commit Them
(London: Tavistock Publications, 1964). As Willet noted: “Some years ago a contest was arranged between two cars to be driven across a city area. One driver had to observe all signs, traffic lights, and speed regulations. The other was allowed to ignore all three if he could do so without endangering the lives of other road users. The law-breaking motorist arrived at this destination just—and only just—ahead of his law-abiding antagonist” (p. 129).

“without a hitch”: The eBay quote comes from Theresa Howard, “Ads Pump up eBay Community with Good Feelings,”
USA Today,
October 17, 2004.

more in revenue: Paul Resnick, Richard Zeckhauser, John Swanson, and Kate Lockwood, “The Value of Reputation on eBay: A Controlled Experiment.” John F. Kennedy School of Government, Harvard University; Working Paper No. RWP03-007.

(provided it’s authentic): See, for example, John Morgan and Jennifer Brown, “Reputation in Online Auctions: The Market for Trust,”
California Management Review,
Fall 2006. About 98 percent of feedback on eBay is positive, which has led economist Axel Ockenfels of the University of Cologne in Germany to suspect that people may be afraid of negative retaliatory feedback. Ockenfels has worked with eBay to introduce mechanisms that allow users to post honest, negative feedback with less fear of reprisal. See Christoph Uhlhaas, “Is Greed Good?”
Scientific American Mind,
August–September 2007, p. 67.

“rising insurance premiums”: Lior J. Strahilevitz, “How’s My Driving? For Everyone (and Everything?),” Public Law and Legal Theory Working Paper No. 125, Law School, University of Chicago. Accessed from
http://ssrn.com/abstract_id=899144
.

have been tried: The Web site
uncivilservants.org
, for example, posts pictures of New York City cars with various official parking permits that are nonetheless parked illegally (many cars also have bootleg parking permits).

actual driving record: C. E. Preston and S. Harris, “Psychology of Drivers in Traffic Accidents,”
Journal of Applied Psychology,
vol. 49 (1965), pp. 284–88.

they were “better”: For a good summary of these studies, see D. Walton and J. Bathurst, “An Exploration of the Perceptions of the Average Driver’s Speed Compared with Perceived Driver Safety and Driving Skill,”
Accident Analysis & Prevention,
vol. 30 (1998), 821–30.

most dangerous thing: John Groeger, a psychologist at the University of Surrey in England, points out that this behavior may be a way to “protect ourselves from the anxieties involved in constantly placing ourselves at risk by developing confidence in our ability which we are rarely likely to be forced to realize is misplaced.” See Groeger,
Understanding Driving
(East Sussex: Psychology Press, 2001), p. 163.

smallest
returns: Brad M. Barber and Terrance Odean, “Trading Is Hazardous to Your Wealth: The Common Stock Investment Performance of Individual Investors,”
Journal of Finance,
vol. 55, no. 2 (2000).

car accident: Julie M. Kos and Valerie A. Clarke, “Is Optimistic Bias Influenced by Control or Delay?”
Health Education Research: Theory and Practice,
vol. 16, no. 5 (2001), pp 533–40.

have done it: The texting while driving poll comes from Reuters, August 7, 2007. Retrieved from
http://www.reuters.com/article/idUSN0640649920070807
.

underestimate our own risk: For an interesting discussion of this phenomenon in the context of seat-belt usage, see “Unconscious Motivators and Situational Safety Belt Use,”
Traffic Safety Facts: Traffic Tech,
No. 315 (Washington, D.C.: National Highway Traffic Safety Administration, 2007).

social mores and traffic laws: For a seminal discussion of these problems, see H. Laurence Ross, “Traffic Law Violation: A Folk Crime,”
Social Problems,
vol. 8, no. 3 (1960–61) pp. 231–41.

in question are ambiguous: See R. B. Felson, “Ambiguity and Bias in the Self-Concept,”
Social Psychology Quarterly,
vol. 44 (March 1981), pp. 64–69.

“unskilled and unaware of it”: Justin Kruger and David Dunning, “Unskilled and Unaware of It: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-Assessments,”
Journal of Personality and Social Pscyhology,
vol. 77, no. 6, (1999), pp. 1121–34.

“better” (i.e., safer) drivers: E. Kunkel, “On the Relationship Between Estimate of Ability and Driver Qualification,”
Psychologie und Praxis,
vol. 15 (1971), pp. 73–80.

(particularly men): See Frank P. McKenna, Robert A. Stanier, and Clive Lewis, “Factors Underlying Illusory Self-Assessment of Driving Skill in Males and Females,”
Accident Analysis & Prevention,
vol. 23, no. 1 (1991), pp. 45–52.

outnumbered the courteous:
New Jersey Star-Ledger,
September 28, 1998.

by low self-esteem: Mayer Perry writes, for example, that “if an individual lacks ‘personal drive’ or dominance, either is easily afforded in the driving situation, and in compensating for this lack, he frequently over-compensates.” Perry,
Aggression on the Road
(London: Tavistock, 1968), p. 7.

promotes aggressive driving: George E. Schreer, “Narcissism and Aggression: Is Inflated Self-Esteem Related to Aggressive Driving?”
North American Journal of Psychology,
vol. 4, no. 3 (2002), pp. 333–42.

claim to have had: See Gina Kolata, “The Median, the Math, and the Sex,”
New York Times,
August 19, 2007.

than doing it: See “Aggravating Circumstances,” a report produced by Public Agenda (available at
http://www.publicagenda.com
). It could be, of course, that the people in the sample (maybe the kind of people who answer surveys) just happened to be an extraordinarily well-behaved group of drivers who really were subject to an inordinate number of louts (the sort who do not answer surveys). There could also be recall bias at work; it is far easier to remember the isolated aggressive acts of others than the uneventful stream of well-behaved driving. This in itself, however, would not explain why people’s perceptions would have changed over time.

“view of the self”: J. M. Twenge, S. Konrath, J. D. Foster, W. K. Campbell, and B. J. Bushman,
Egos Inflating over Time: A Test of Two Generational Theories of Narcissism,
2006. Cited in “Primary Sources,”
Atlantic,
July–August 2007.

attributes to police officers: Still, getting a ticket may be a form of at least temporarily effective feedback: One study, looking at ten million Ontario drivers for more than a decade, found that each conviction for a traffic offense led to a 35 percent decrease in relative risk of death over the next month for that driver and others. See Donald A. Redelmeier, Robert J. Tibsharani, and Leonard Evans, “Traffic-Law Enforcement and Risk of Death from Motor-Vehicle Crashes: Case-Crossover Study,”
Lancet,
vol. 361, no. 9376 (2003), pp. 2177–82.

“experience is a mixed blessing”: James Reason,
Human Error
(Cambridge: Cambridge University Press, 1990), p. 86.