"things you can do": Ralph Vartabadian, "Your Wheels," Los Angeles Times, Los Angeles Times, May 14, 2003. May 14, 2003.

"explicit argument": The quote about convex mirrors comes from a telephone interview with Michael Flannagan.

insurance company surveys: A 2002 survey by Progressive Insurance, for example, which queried more than eleven thousand drivers who had filed a claim for a crash in 2001, found that 52 percent of the accidents occurred within five miles of the driver's home, and 77 percent occurred within fifteen miles of the home. Retrieved on October 3, 2007, from http://newsroom.progressive.com/2002/May/fivemiles.aspx.

A study by: See, for example, Tova Rosenbloom, Amotz Perlmana, and Amit Shahara, "Women Drivers' Behavior in Well-known Versus Less Familiar Locations," Journal of Safety Research, Journal of Safety Research, vol. 38, issue 3, 2007, pp. 28388. Studies have also shown drivers are less likely to wear seat belts on shorter trips, which would seem to indicate a feeling of greater safety close to home. See, for one, David W. Eby, Lisa J. Molnar, Lidia P. Kostyniuk, Jean T. Shope, and Linda L. Miller, "Developing an Optimal In-Vehicle Safety Belt Promotion System" (Ann Arbor: University of Michigan Transportation Research Inst.i.tute, 2004). vol. 38, issue 3, 2007, pp. 28388. Studies have also shown drivers are less likely to wear seat belts on shorter trips, which would seem to indicate a feeling of greater safety close to home. See, for one, David W. Eby, Lisa J. Molnar, Lidia P. Kostyniuk, Jean T. Shope, and Linda L. Miller, "Developing an Optimal In-Vehicle Safety Belt Promotion System" (Ann Arbor: University of Michigan Transportation Research Inst.i.tute, 2004).

food or health care: Driven to Spend Driven to Spend (Surface Transportation Policy Project, 2001). (Surface Transportation Policy Project, 2001).

more own three than own one: Alan Pisarski, Commuting in America III Commuting in America III (Washington, D.C.,: Transportation Research Board, 2006), p. 38. (Washington, D.C.,: Transportation Research Board, 2006), p. 38.

has a three-car garage: Amy Orndorff, "Garages Go Gigantic: Car Buffs Opt for Bigger s.p.a.ces," Washington Post, Washington Post, September 13, 2006. September 13, 2006.

thirty-eight hours annually: See Tim Lomax and David Schrank, 2007 Annual Urban Mobility Report, 2007 Annual Urban Mobility Report, compiled for the Texas Transportation Inst.i.tute (College Station: Texas A&M University, 2007). compiled for the Texas Transportation Inst.i.tute (College Station: Texas A&M University, 2007).

by nearly half: Surface Transportation Policy Partnership, Mean Streets 2002, Mean Streets 2002, chapter 2. Retrieved at chapter 2. Retrieved at http://www.transact.org/report.asp?id=159.

"food and beverage venue": This phrase comes from Food and Drug Packaging, Food and Drug Packaging, March 2002. March 2002.

there were 504: Frozen Food Age, Frozen Food Age, vol. 54, no. 1 (August 2005), p. 38. vol. 54, no. 1 (August 2005), p. 38.

84.4 billion in 2008: On-the-go eating figures come from the market research firm Datamonitor.

gentler, slower age: Drive-through sales figure comes from the Wall Street Journal, Wall Street Journal, May 21, 2000. May 21, 2000.

through a car window: Chicago Sun-Times, Chicago Sun-Times, October 7, 2005. October 7, 2005.

at least once per week: According to a survey commissioned by the Food Strategy Implementation Partnership (FSIP), Bord Bia, and Intertrade Ireland, and carried out by Invest NI, as quoted in Checkout, Checkout, February 2006. February 2006.

in order to speed traffic: Julie Jargon, "McD's Aims for the Fast Lane." Crain's Chicago Business, Crain's Chicago Business, June 27, 2005, p. 3. The article does note that the two ordering lanes must merge into one paying lane; there is no word of any reported merging difficulties. June 27, 2005, p. 3. The article does note that the two ordering lanes must merge into one paying lane; there is no word of any reported merging difficulties.

burgeoning drive-through customers: Geoffrey Fowler, "Drive-Through Tips for China," Wall Street Journal, Wall Street Journal, June 20, 2006. June 20, 2006.

company-owned stores: Elizabeth M. Gillespie, "Starbucks Bows to Customer Demand," Toronto Star, Toronto Star, December 27, 2005. December 27, 2005.

"handle well in the car": This quote comes from a press release accessed through Business Wire, retrieved at http://www.hispanicprwire.com/news.php?l=in&id=4394&cha=4. The dashboard-dining test was performed by Kelton Research; it was the firm's CEO, Tom Bernthal, whom I met with to discuss the test.

drive-through window: Carole Paquette, "Drive-Throughs Move Beyond Banks and Fast Food," New York Times, New York Times, April 8, 2001. April 8, 2001.

Audio Publishers a.s.sociation: Information on audiobooks comes from doc.u.ments provided by the Audio Publishers a.s.sociation.

to bear in L.A. traffic: Idan Ivri, "Gridlock: How Traffic Has Rerouted Jewish Life," Jewish Journal, Jewish Journal, July 9, 2004. The political scientist Robert Putnam suggests that every ten minutes of commute time July 9, 2004. The political scientist Robert Putnam suggests that every ten minutes of commute time "cuts involvement in community affairs by 10 percent" "cuts involvement in community affairs by 10 percent" (Putnam's italics); from Putnam, (Putnam's italics); from Putnam, Bowling Alone: The Collapse and Revival of American Community Bowling Alone: The Collapse and Revival of American Community (New York: Simon and Schuster, 2001), p. 213. (New York: Simon and Schuster, 2001), p. 213.

on their left sides: Based on research by Scott Fosko, Saint Louis University School of Medicine. Article retrieved from: http://www.aad.org/aad/Newsroom/Driving+An+Automobile.htm.

"toward the same horizon": From Alexis de Tocqueville, Democracy in America Democracy in America (repr.; London: Penguin, 2003), p. 328. (repr.; London: Penguin, 2003), p. 328.

double since 1990: Elizabeth Rosenthal, "Car Boom Puts Europe on Road to a Smoggy Future," New York Times, New York Times, January 7, 2007. January 7, 2007.

underground parking garages: "Car Ownership Boom Means Traffic Jams in Once-Tranquil Tibet," International Herald Tribune, International Herald Tribune, November 7, 2007. November 7, 2007.

Caracas: Rory Carroll, "Carbon Leaves Caracas in One Big Jam," Guardian, Guardian, November 23, 2006. The "seven cents" gas figure comes from Simon Romero, "Venezuela Hands Narrow Defeat to Chavez Plans," November 23, 2006. The "seven cents" gas figure comes from Simon Romero, "Venezuela Hands Narrow Defeat to Chavez Plans," New York Times, New York Times, October 30, 2007. October 30, 2007.

the legendary traffic: In a 2004 estimate, So Paulo was said to have just under four miles of freeways to accommodate more than five million vehicles. Los Angeles, by contrast, had nine hundred miles to handle about seven million vehicles. See Henry Chu, "So Paulo Seeks Road Map to Life Without Traffic Jams," Los Angeles Times, Los Angeles Times, November 9, 2004. In 2007, a rising number of fatal helicopter crashes was prompting calls to limit the growing airborne traffic. See Cristina Christiano, "SP quer limitar trafego de helicopteros," November 9, 2004. In 2007, a rising number of fatal helicopter crashes was prompting calls to limit the growing airborne traffic. See Cristina Christiano, "SP quer limitar trafego de helicopteros," O Globo, O Globo, September 24, 2007. September 24, 2007.

faster car-pool lanes: Matthew Moore, "Car Jockeys Often in for Rough Ride from Traffic Police," Sydney Morning Herald, Sydney Morning Herald, December 26, 2002. December 26, 2002.

human "nav system": This information came via an e-mail correspondence with Jian Shou w.a.n.g.

cause of death: World Health Organization. Retrived from: http://www.who.int/world-health-day/2004/infomaterials/en/brochure_jan04_en.pdf.

Chapter One: Why Does the Other Lane Always Seem Faster?.

"modal bias": This term was suggested to me in a conversation with Aaron Naparstek.

"change of mode": Helene Fontaine and Yves Gourlet, "Fatal Pedestrian Accidents in France: A Typological a.n.a.lysis," Accident a.n.a.lysis and Prevention, Accident a.n.a.lysis and Prevention, vol. 39, no. 3 (1997), pp. 30312. vol. 39, no. 3 (1997), pp. 30312.

"drives as he lives": W. A. Tillman and G. E. Hobbs, "The Accident-p.r.o.ne Automobile Driver: A Study of the Psychiatric and Social Background," American Journal of Psychiatry, American Journal of Psychiatry, vol. 106 (November 1949), pp. 32131. Many of us may think of "road rage" as a rather new concept, like "air rage" or "surfing rage," but it is really as old as the automobile itself. The year 1968, for example, might have been marked by violent social upheaval in metropolises from Paris to Mexico City, but there was another form of violence in the air: That year, Mayer H. Parry published vol. 106 (November 1949), pp. 32131. Many of us may think of "road rage" as a rather new concept, like "air rage" or "surfing rage," but it is really as old as the automobile itself. The year 1968, for example, might have been marked by violent social upheaval in metropolises from Paris to Mexico City, but there was another form of violence in the air: That year, Mayer H. Parry published Aggression on the Road, Aggression on the Road, while the while the New York Times New York Times reported on government testimony about "uncontrollable violent behavior" on the nation's roads. (Three years later, F. A. Whitlock followed up with his book reported on government testimony about "uncontrollable violent behavior" on the nation's roads. (Three years later, F. A. Whitlock followed up with his book Death on the Road: A Study in Social Violence. Death on the Road: A Study in Social Violence.) See John D. Morris, "Driver Violence Tied to Crashes," New York Times, New York Times, March 2, 1968. March 2, 1968.

risks on the road: For a discussion, see Patrick L. Brockett and Linda L. Golden, "Biological and Psychobehavioral Correlates of Credit Scores and Automobile Insurance Losses: Toward an Explication of Why Credit Scoring Works," Journal of Risk and Insurance, Journal of Risk and Insurance, vol. 1, no. 74 (March 2007), pp. 2363. vol. 1, no. 74 (March 2007), pp. 2363.

typically involve questionnaires: See, for example, David L. Van Rooy, James Rotton, and Tina M. Burns, "Convergent, Discriminant, and Predictive Validity of Aggressive Driving Inventories: They Drive as They Live," Aggressive Behavior, Aggressive Behavior, vol. 3, no. 2 (February 2006), pp. 8998. vol. 3, no. 2 (February 2006), pp. 8998.

more aggressive manner: This is a virtual consensus in the field, as demonstrated by a survey of the scholarly literature in B. A. Jonah, "Sensation Seeking and Risky Driving: A Review and Synthesis of the Literature," Accident a.n.a.lysis and Prevention, Accident a.n.a.lysis and Prevention, vol. 29, no. 5 (1997), pp. 65165. vol. 29, no. 5 (1997), pp. 65165.

"Traffic tantrums": Thanks to Ian Walker for this phrase.

especially by novice drivers: Kazumi Renge, "Effect of Driving Experience on Drivers' Decoding Process of Roadway Interpersonal Communication," Ergonomics, Ergonomics, vol. 43, no. 1 (1 January 2000), pp. 2739. vol. 43, no. 1 (1 January 2000), pp. 2739.

Green Day b.u.mper sticker: This brings up the point of whether there should really be any nonessential communication in traffic at all. As the German sociologist Norbert Schmidt-Relenberg has observed, "It could be said that cooperation in traffic is not a means to attain something positive, but to avoid something negative: every partic.i.p.ant in the system attempts to attain his destination without friction. Hence traffic is a system all its own; the less its partic.i.p.ants come into contact with each other and are compelled to interaction, the better it works: a system defined and approved in the reality by a principle of minimized contact." In other words, not only should we not honk at people with Green Day stickers, we should not put the sticker there in the first place. Norbert Schmidt-Relenberg, "On the Sociology of Car Traffic in Towns," in Transport Sociology: Social Aspects of Transport Planning, Transport Sociology: Social Aspects of Transport Planning, ed. Enne de Boer (Oxford, New York: Pergamon Press, 1986), p. 122. ed. Enne de Boer (Oxford, New York: Pergamon Press, 1986), p. 122.

violated traffic laws: Maria Cristina Caballero, "Academic Turns City into a Social Experiment," Harvard University Gazette, Harvard University Gazette, March 11, 2004. March 11, 2004.

a.s.sociated with subordination: Katz suggests this may be why we so often call other drivers "a.s.sholes" and give the "up yours" finger.

by the honker: Andrew R. McGarva and Mich.e.l.le Steiner, "Provoked Driver Aggression and Status: A Field Study," Transportation Research F: Psychology and Behavior, Transportation Research F: Psychology and Behavior, vol. 167 (2000), pp. 167179. vol. 167 (2000), pp. 167179.

anything but rude or hostile: What if our signals were more meaningful? A few years ago, before the Tokyo Motor Show, Simon Humphries, a designer for Lexus in j.a.pan, told me in an e-mail exchange that the Toyota Motor Company had proposed a car-nicknamed POD-that would contain a "vehicle expression operation control system." Accompanying the usual lights and arrows would be a new range of signals. The headlights would be "anthropomorphized" with "eyes" and "eyebrows," the antenna would "wag," and different colors would be used to show emotion. "As traffic grows heavier and vehicle use increases," reads the U.S. patent application, "vehicles having expression functions, such as crying or laughing, like people and other animals do, could create a joyful, organic atmosphere rather than the simple comings and goings of inorganic vehicles." Indeed, a German company even released an aftermarket version of this system, called Flashbox, that uses a series of blinks to signify things like "apology," "annoyed," and "stop for more?" Adding signals, however, creates many new problems. Everyone has to learn the new signals. More information in traffic means more time to process. The receiver of a "smile," moreover, may not understand why they have received it any more so than a honk. And flashing "angry" signals may provoke rather than defuse violence.

deficient male anatomy: One male Australian driver was actually fined because when a woman wagged her pinkie at him, he responded by hurling a plastic bottle at her windshield. The man claimed that the gesture was akin to a "s.e.xual a.s.sault," a worse insult than the traditional finger. "The 'finger,' it's so common now, that we're over it, but this finger is a whole new thing and it's been promoted so much everybody knows it and you just get offended," he said. David Brouithwaite, "Driver Points to Ad Campaign for His Digitally Enhanced Road Rage," The Sydney Morning Herald, The Sydney Morning Herald, November 1, 2007. November 1, 2007.

"constructing moral dramas": For a more detailed discussion of Katz's investigation of anger in traffic, see Jack Katz, How Emotions Work How Emotions Work (Chicago: University of Chicago Press, 1999), in particular the first chapter, "p.i.s.sed Off in L.A." (Chicago: University of Chicago Press, 1999), in particular the first chapter, "p.i.s.sed Off in L.A."

"the angry driver": Jack Katz, How Emotions Work, How Emotions Work, p. 48. p. 48.

"actor-observer effect": See L. D. Ross, "The Intuitive Psychologist and His Shortcomings: Distortions in the Attribution Process," in Advances in Experimental Social Psychology, Advances in Experimental Social Psychology, vol. 10, ed. L. Berkowitz (New York: Random House, 1977), pp. 173220. vol. 10, ed. L. Berkowitz (New York: Random House, 1977), pp. 173220.

feel more in control: As Thomas Britt and Michael Garrity write, "individuals will probably err in the direction of a.s.suming an internal locus of causality for the offending driver's behavior in order to feel some sense of control over events when driving." "Attributions and Personality as Predictors of the Road Rage Response," British Journal of Social Psychology, British Journal of Social Psychology, vol. 45 (2006), pp. 12747. vol. 45 (2006), pp. 12747.

required by the circ.u.mstances: This was the finding arrived at when a group of researchers for England's Transport Research Laboratory conducted a series of interviews with drivers, part of which included a.s.sessments of cyclist and driver behavior in traffic scenarios. They concluded, "The underlying unpredictability of cyclists' behavior was seen by drivers as stemming from the att.i.tudes and limited competence of the cyclists themselves, rather than from the difficulty of the situations that cyclists are often forced to face on the road (i.e., drivers made a dispositional rather than a situational attribution). Despite their own evident difficulties in knowing how to respond, drivers never attributed these difficulties to their own att.i.tudes or competencies, nor did they do so in relation to other drivers (i.e. they made a situational attribution about their own and other drivers' behavior). This pattern of a.s.signment of responsibility is characteristic of how people perceive the behavior of those they consider to be part of the same social group as themselves, versus those seen as part of a different social group." L. Basford, D. Davies, J. A. Thomson, and A. K. Tolmie, "Drivers' Perception of Cyclists," in TRL Report 549: Phase I-a Qualitative Study TRL Report 549: Phase I-a Qualitative Study (Crowthorne: Transport Research Laboratory, 2002). (Crowthorne: Transport Research Laboratory, 2002).

shares their birth date: See D. T. Miller, J. S. Downs, and D. A. Prentice, "Minimal Conditions for the Creation of a Unit Relationship: The Social Bond Between Birthday Mates," European Journal of Social Psychology, European Journal of Social Psychology, vol. 28 (1998), pp. 47581. This idea was raised in an interesting paper by James W. Jenness, "Supporting Highway Safety Culture by Addressing Anonymity," vol. 28 (1998), pp. 47581. This idea was raised in an interesting paper by James W. Jenness, "Supporting Highway Safety Culture by Addressing Anonymity," AAA Foundation for Traffic Safety, AAA Foundation for Traffic Safety, 2007. 2007.

Katz says, cyborgs: This point was made as early as 1930, by a city planner in California who suggested that "Southern Californians have added wheels to their anatomy." The quote comes from J. Flink, The Automobile Age The Automobile Age (Cambridge, Ma.s.s: MIT Press, 1988), p. 143, via an excellent article by John Urry, a sociologist at Lancaster University. See John Urry, "Inhabiting the Car," published by the Department of Sociology, Lancaster University, Lancaster, United Kingdom, available at (Cambridge, Ma.s.s: MIT Press, 1988), p. 143, via an excellent article by John Urry, a sociologist at Lancaster University. See John Urry, "Inhabiting the Car," published by the Department of Sociology, Lancaster University, Lancaster, United Kingdom, available at http://www.comp.lancs.ac.uk/sociology/papers/Urry-Inhabiting-the-Car.pdf.

different people: See Henrik Walter, Sandra C. Vetter, Jo Grothe, Arthur P. Wunderlich, Stefan Hahn, and Manfred Spitzer, "The Neural Correlates of Driving," Brain Imaging, Brain Imaging, vol. 12, no. 8 (June 13, 2001), pp. 176367. vol. 12, no. 8 (June 13, 2001), pp. 176367.

and following distance: See David Shinar and Richard Compton, "Aggressive Driving: An Observational Study of Driver, Vehicle and Situational Variables," Accident a.n.a.lysis & Prevention, Accident a.n.a.lysis & Prevention, vol. 36 (2004), pp. 42937. vol. 36 (2004), pp. 42937.

give themselves over to the car: Research also suggests that single drivers are more susceptible to fatigue and being involved in crashes, and it is not difficult to speculate why. Pa.s.sengers provide another "set of eyes" to warn of potential hazards and can aid in keeping the driver engaged. For the increased risk factors to single drivers see, for example, Vicki L. Neale, Thomas A. Dingus, Jeremy Sudweeks, and Michael Goodman, "An Overview of the 100-Car Naturalistic Study and Findings." National Highway Traffic Safety Administration, Paper Number 05-0400.

thirty-three citations: See F. K. Heussenstamm, "b.u.mper Stickers and the Cops," Trans-Action (Society), Trans-Action (Society), vol. 8 (February 1971), pp. 32 and 33. The author acknowledged that the subjects' driving may have been affected by the experiment itself but argued that "it is statistically unlikely that this number of previously 'safe' drivers could ama.s.s such a collection of tickets without a.s.suming real bias by police against drivers with Black Panther b.u.mper stickers." The information about specially designated license plates comes from "New 'Scarlet Letter' for Predators in Ohio," a.s.sociated Press, March 1, 2007. The license plates raise, ironically, a problem similar to "Children at Play" signs: They signify that a car without such plates is somehow safe for children to approach, just as the "Children at Play" signs suggest that drivers can act less cautiously in areas vol. 8 (February 1971), pp. 32 and 33. The author acknowledged that the subjects' driving may have been affected by the experiment itself but argued that "it is statistically unlikely that this number of previously 'safe' drivers could ama.s.s such a collection of tickets without a.s.suming real bias by police against drivers with Black Panther b.u.mper stickers." The information about specially designated license plates comes from "New 'Scarlet Letter' for Predators in Ohio," a.s.sociated Press, March 1, 2007. The license plates raise, ironically, a problem similar to "Children at Play" signs: They signify that a car without such plates is somehow safe for children to approach, just as the "Children at Play" signs suggest that drivers can act less cautiously in areas without without the signs. the signs.

aggressive driving on her part: Women driving SUVs, as at least one set of very limited observational studies found, drove faster in 20-mile-per-hour school zones, parked more often in restricted shopping mall fire zones, came to a stop less frequently at stop signs, and were slower to move through an intersection when the light turned green, as compared to other drivers in other types of vehicles. As the author himself admits, the sample sizes were small, and the higher rates of women SUV drivers may simply have reflected the fact that the study took place in a setting where there happened to be a higher than average number of women driving SUVs. See John Trinkaus, "Shopping Center Fire Zone Parking Violators: An Informal Look," Perceptual and Motor Skills, Perceptual and Motor Skills, vol. 95 (2002), pp. 121516; John Trinkaus, "School Zone Speed Limit Dissenters: An Informal Look," vol. 95 (2002), pp. 121516; John Trinkaus, "School Zone Speed Limit Dissenters: An Informal Look," Perceptual and Motor Skills, Perceptual and Motor Skills, vol. 88 (1999), pp. 105758. vol. 88 (1999), pp. 105758.

at greater risk: See, for example, Devon E. Lefler and Hampton C. Gabler, "The Fatality and Injury Risk of Light Truck Impacts with Pedestrians in the United States," Accident a.n.a.lysis & Prevention, Accident a.n.a.lysis & Prevention, vol. 36 (2004), pp. 295304. vol. 36 (2004), pp. 295304.

"grieving while driving": Paul C. Rosenblatt, "Grieving While Driving," Death Studies, Death Studies, vol. 28, (2004), pp. 67986. vol. 28, (2004), pp. 67986.

including nasal probing: Thanks to Daniel McGehee for this story.

not wearing hoods: Philip Zimbardo. "The Human Choice: Individuation, Reason, and Order vs. Deindividuation, Impulse, and Chaos." In Nebraska Symposium on Motivation, Nebraska Symposium on Motivation, ed. W. J. Arnold and D. Levine (Lincoln: University of Nebraska Press, 1970). Zimbardo's description of the conditions that contribute to the sense of "deindividuation" are worth noting in light of traffic. He writes: "Anonymity, diffused responsibility, group activity, altered temporal perspective, emotional arousal, and sensory overload are some of the input variables that can generate deindividuated reactions." Arguably, ed. W. J. Arnold and D. Levine (Lincoln: University of Nebraska Press, 1970). Zimbardo's description of the conditions that contribute to the sense of "deindividuation" are worth noting in light of traffic. He writes: "Anonymity, diffused responsibility, group activity, altered temporal perspective, emotional arousal, and sensory overload are some of the input variables that can generate deindividuated reactions." Arguably, all all of Zimbardo's "input variables" can routinely be found in traffic situations. The quote comes from Zimbardo's "Depersonalization" entry in of Zimbardo's "input variables" can routinely be found in traffic situations. The quote comes from Zimbardo's "Depersonalization" entry in International Encyclopedia of Psychiatry, Psychology, Psychoa.n.a.lysis, and Neurology, International Encyclopedia of Psychiatry, Psychology, Psychoa.n.a.lysis, and Neurology, vol. 4, ed. B. B. Wolman (New York: Human Sciences Press, 1978), p. 52. vol. 4, ed. B. B. Wolman (New York: Human Sciences Press, 1978), p. 52.

to the executioners: The hostage and firing squad information comes from David Grossman, On Killing: The Psychological Cost of Learning to Kill in War and Society On Killing: The Psychological Cost of Learning to Kill in War and Society (Boston: Back Bay Books, 1996), p. 128. (Boston: Back Bay Books, 1996), p. 128.

with the tops up: Patricia A. Ellison, John M. Govern, Herbert L. Petri, Michael H. Figler, "Anonymity and Aggressive Driving Behavior: A Field Study," Journal of Social Behavior and Personality, Journal of Social Behavior and Personality, vol. 10, no. 1 (1995), pp. 26572. vol. 10, no. 1 (1995), pp. 26572.

"online disinhibition effect": See J. Suler, "The Online Disinhibation Effect," CyberPsychology and Behavior, CyberPsychology and Behavior, vol. 7 (2004), pp. 32126. vol. 7 (2004), pp. 32126.

relatively large social networks: See, for example, R. I. M. Dunbar, "Neocortical Size as a Constraint on Group Size in Primates," Journal of Human Evolution, Journal of Human Evolution, vol. 22 (1993), pp. 46993. vol. 22 (1993), pp. 46993.

higher testosterone levels: Roxanne Khamsi, "Hormones Affect Men's Sense of Fair Play," New Scientist, New Scientist, July 4, 2007. July 4, 2007.

"strong reciprocity": See Ernst Fehr, Urs Fischbacher, and Simon Gachter, "Strong Reciprocity, Human Cooperation and the Enforcement of Social Norms," Human Nature, Human Nature, vol. 13 (2002), pp. 125. vol. 13 (2002), pp. 125.

altruistic all the same: The comments on road rage from Herbert Gintis come from an interview posted at www.innoarticles.com. The example of the bird signaling a predator's approach comes from Olivia Judson, "The Selfish Gene," Atlantic Monthly, Atlantic Monthly, October 2007, p. 92. It has also been speculated that animals raising an alarm against a predator are actually sending a signal to the October 2007, p. 92. It has also been speculated that animals raising an alarm against a predator are actually sending a signal to the predator predator that it has been spotted. For an interesting theoretical discussion, see C. T. Bergstrom and M. Lachmann, "Alarm Calls as Costly Signals of Antipredator Vigilance: The Watchful Babbler Game," that it has been spotted. For an interesting theoretical discussion, see C. T. Bergstrom and M. Lachmann, "Alarm Calls as Costly Signals of Antipredator Vigilance: The Watchful Babbler Game," Animal Behaviour, Animal Behaviour, vol. 61 (2001), pp. 53543. vol. 61 (2001), pp. 53543.

around 20 miles per hour: Ben Hamilton-Baillie, "Improving Traffic Behaviour and Safety Through Urban Design," Civil Engineering, Civil Engineering, vol. 158 (May 2005), pp. 3947. vol. 158 (May 2005), pp. 3947.

result was the same: P. C. Ellsworth, J. M. Carlsmith, and A. Henson, "The Stare as a Stimulus to Flight in Human Subjects: A Series of Field Experiments," Journal of Personality and Social Psychology, Journal of Personality and Social Psychology, vol. 21 (1972), pp. 30211. vol. 21 (1972), pp. 30211.

were not present: Kevin J. Haley and Daniel M. T. Fessler, "n.o.body's Watching? Subtle Cues Affect Generosity in an Anonymous Economic Game," Evolution and Human Behavior, Evolution and Human Behavior, vol. 26 (2005), pp. 24556. vol. 26 (2005), pp. 24556.

university break room: See Melissa Bateson, Daniel Nettle, and Gilbert Roberts, "Cues of Being Watched Enhance Cooperation in a Real-World Setting," Biology Letters, Biology Letters, June 2, 2006. June 2, 2006.

cooperation in humans: Michael Tomasello, Brian Hare, Hagen Lehmann, and Josep Call, "Reliance on Head Versus Eyes in the Gaze Following of Great Apes and Human Infants: The Cooperative Eye Hypothesis," Journal of Human Evolution, Journal of Human Evolution, vol. 52 (2007), pp. 31420. vol. 52 (2007), pp. 31420.

direction of one's gaze: Smiling might help as well, at least if you're female and the person you're smiling at is male, a French study showed. The study had male and female subjects try to hitch rides by smiling or not smiling at pa.s.sing drivers. More women received rides when they smiled, but for men, alas, this did not work. Also, every driver that stopped was male. Nicolas Guegue and Jacques Fischer-Lokou, "Hitchhikers' Smiles and Receipt of Help," Psychological Reports, Psychological Reports, vol. 94, (2004), pp. 75660. vol. 94, (2004), pp. 75660.

tilt your head up: Michael Tomasello, Brian Harea, Hagen Lehmanna, and Josep Call, "Reliance on Head Versus Eyes in the Gaze Following of Great Apes and Human Infants: The Cooperative Eye Hypothesis," Journal of Human Evolution, Journal of Human Evolution, vol. 52, no. 3 (March 2007), pp. 31420. vol. 52, no. 3 (March 2007), pp. 31420.

if one does not make eye contact: Robert Wright explains this phenomenon succinctly: "When we pa.s.s a homeless person, we may feel uncomfortable about failing to help. But what really gets the conscience twinging is making eye contact and still failing to help. We don't seem to mind not giving nearly so much as we mind being seen not giving." (As for why we should care about the opinion of someone we'll never encounter again: Perhaps in our ancestral environment, just about everyone encountered was someone we might well encounter again.) From The Moral Animal The Moral Animal (New York: Alfred A. Knopf, 1994), p. 206. (New York: Alfred A. Knopf, 1994), p. 206.

"if there are more than two": Thomas Sch.e.l.ling, Choice and Consequence Choice and Consequence (Cambridge, Ma.s.s.: Harvard University Press, 1984), p. 214. (Cambridge, Ma.s.s.: Harvard University Press, 1984), p. 214.

first through the intersection: Sch.e.l.ling also suggested throwing one's steering wheel out the window as a sign that one has committed to one's course of action.

at the oncoming car: A. Katz, D. Zaidel, and A. Elgrishi. "An Experimental Study of Driver and Pedestrian Interaction During the Crossing Conflict," Human Factors, Human Factors, vol. 17, no. 5 (1975), pp. 51427. vol. 17, no. 5 (1975), pp. 51427.

Or was it just chivalry?: Jeffrey Z. Rubin, Bruce D. Steinberg, and John R. Gerrein, "How to Obtain the Right of Way: An Experimental a.n.a.lysis of Behavior at Intersections," Perceptual and Motor Skills, Perceptual and Motor Skills, vol. 34 (1974), pp. 126374. vol. 34 (1974), pp. 126374.

in New York City: Of course, the faster pace of life in New York City also has an affect on the traffic culture. Michael Primeggia, the deputy director of the New York City Department of Transportation, told me the following joke: "What's the shortest amount of recorded time? The time between the light turning green in New York and the horn sounding."

visibly express anger: Andrew R. McGarva, Matthew Ramsey, and Suzannah A. Shear, "Effects of Driver Cell-Phone Use on Driver Aggression," Journal of Social Psychology, Journal of Social Psychology, vol. 146, no. 2 (2006), pp. 13346. vol. 146, no. 2 (2006), pp. 13346.

replicated in Australia: S. Bochner, "Inhibition of Horn-Sounding as a Function of Frustrator's Status and s.e.x: An Australian Replication and Extension of Doob and Gross," Australian Journal of Psychology, Australian Journal of Psychology, vol. 6 (1968), pp. 19499. vol. 6 (1968), pp. 19499.

doing the blocking: A. N. Doob and A. E. Gross, "Status of Frustrator as an Inhibitor of Horn-Honking Responses," Journal of Social Psychology, Journal of Social Psychology, vol. 76 (1968), pp. 21318. vol. 76 (1968), pp. 21318.

you guessed right: Andreas Diekmann, Monika Jungbauer-Gans, Heinz Kra.s.snig, Heinz Lorenz, and Sigrid Lorenz, "Social Status and Aggression: A Field Study a.n.a.lyzed by Survival a.n.a.lysis," Journal of Social Psychology; Journal of Social Psychology; vol. 136, no. 6 (December 1996), pp. 76168. vol. 136, no. 6 (December 1996), pp. 76168.

been at work: See Ben Jann, "Driver Aggression as a Function of Status Concurrence: An a.n.a.lysis of Horn-Honking Responses," Bern, Switzerland, 2002; available at www.socio.ethz.ch/de/jann. Interestingly, this study found, as in the earlier mentioned birthday study, that drivers of a vehicle were less likely to honk at a vehicle when it was of the same same status. The researcher noted, however, that "our data do not reveal whether it is actually status. The researcher noted, however, that "our data do not reveal whether it is actually similarity similarity which which reduces reduces aggression or rather aggression or rather difference difference that that increases increases it." it."

when it was a man: Kay Deux, "Honking at the Intersection: A Replication and Extension," Journal of Social Psychology, Journal of Social Psychology, vol. 84 (1971), pp. 15960. vol. 84 (1971), pp. 15960.

a driving "lesson": H. Yazawa, "Effects of Inferred Social Status and a Beginning Driver's Sticker upon Aggression of Drivers in j.a.pan," Psychological Reports, Psychological Reports, vol. 94 (2004), pp. 121520. vol. 94 (2004), pp. 121520.

from another country: The study, interestingly, found that French, Spanish, and Italian drivers were faster to the horn than German drivers (Italians were the fastest). Drivers also honked more when the visible sticker was German and not the less recognizable Australian ident.i.ty sticker. See Joseph P. Forgas, "An Un.o.btrusive Study of Reactions to National Stereotypes in Four European Countries," Journal of Social Psychology, Journal of Social Psychology, vol. 99 (1976), pp. 3742. vol. 99 (1976), pp. 3742.

suspected these things: Drivers, of course, may simply be honking in a "nonaggressive" way simply to let the driver ahead know that the light has changed. But as Dwight Hennessey has pointed out, the frequency and latency of honks indicates that more than just polite signaling is at work. See Dwight Hennessey, "The Interaction of Person and Situation Within the Driving Environment: Daily Ha.s.sles, Traffic Congestion, Driver Stress, Aggression, Vengeance and Past Performance" (Ph.D. dissertation, York University, Toronto, Ontario, April 1999).

In another study: Ian Walker, "Signals Are Informative but Slow Down Responses When Drivers Meet Bicyclists at Road Junctions," Accident a.n.a.lysis & Prevention, Accident a.n.a.lysis & Prevention, vol. 37 (2005), pp. 107485. vol. 37 (2005), pp. 107485.

In a previous study: Ian Walker, "Road Users' Perceptions of Other Road Users: Do Different Transport Modes Invoke Qualitatively Different Concepts in Observers?" Advances in Transportation Studies, Advances in Transportation Studies, section A, no. 6 (2005), pp. 2532. section A, no. 6 (2005), pp. 2532.

rendered invisible by the car: Perhaps the subjects were distracted by simply recognizing the make and model of car. Psychologists at Vanderbilt University have shown in clinical tests that car aficionados shown pictures of cars were less able to identify faces at the same time. Car fanciers were looking at cars as if they were as if they were faces, causing a "perceptual traffic jam" in a part of the brain implicated in the "holistic" visual processes of facial recognition. See Isabel Gauthier and Kim M. Curby, "A Perceptual Traffic Jam on Highway N170: Interference Between Face and Car Expertise," faces, causing a "perceptual traffic jam" in a part of the brain implicated in the "holistic" visual processes of facial recognition. See Isabel Gauthier and Kim M. Curby, "A Perceptual Traffic Jam on Highway N170: Interference Between Face and Car Expertise," Current Directions in Psychological Science, Current Directions in Psychological Science, vol. 14, no. 1 (February 2005), pp. 3033. vol. 14, no. 1 (February 2005), pp. 3033.

people's eyes meet: See, for example, A. Gale, G. Spratt, AJ Chapman, and A. Smallbone, "EEG correlates of eye contact and interpersonal distance," Biological Psychology, Biological Psychology, vol. 3, no. 4 (December 1975), pp. 23745. vol. 3, no. 4 (December 1975), pp. 23745.

to the actual road: For further details on the study, see Ian Walker, "Drivers Overtaking Bicyclists: Objective Data on the Effects of Riding Position, Helmet Use, Vehicle Types and Apparent Gender," Accident a.n.a.lysis & Prevention, Accident a.n.a.lysis & Prevention, vol. 39 (2007), pp. 41725. vol. 39 (2007), pp. 41725.

the driver slows: There is conceivably no limit to the number and variety of stereotypes drivers possess about other vehicles and the people driving them-for example, BMW drivers are aggressive, minivan drivers are slow. How all these secret interactions all play out in traffic is virtually beyond study. Do certain car drivers act a certain way, and do we act differently toward certain cars or drivers? Do you get the finger in a Hummer and a cute smile in a Mini, and does this then affect the way you drive, which then reinforces the stereotype? Research has suggested one drawback of these stereotypes: When subjects were read the description of a crash between two cars in which the actual facts were unknown, they estimated that the speed of one car was higher when the driver was younger and in a stereotypical "boy racer" car. (The effect was even stronger when the color was red!) See Graham M. Davies and Darshana Patel, "The Influence of Car and Driver Stereotypes on Attributions of Vehicle Speed, Position on the Road and Culpability in a Road Accident Scenario," Legal and Criminal Psychology, Legal and Criminal Psychology, vol. 10, (2005), pp. 4562. vol. 10, (2005), pp. 4562.