Traffic (54 page)

not put them up: See
Supplemental Advance Warning Devices: A Synthesis of Highway Practice,
National Cooperative Highway Research Program Synthesis 186 (Washington, D.C.: National Academy Press, 1993), p. 38.

fewer deer had crossed: See T. M. Pojar, D. F. Reed, and T. C. Reseigh, “Effectiveness of a Lighted, Animated Deer Crossing Sign,”
Journal of Wildlife Management,
vol. 39, no. 1 (1975), pp. 87–91.

“deer-vehicle collision”: See K. M. Gordon, S. H. Anderson, B. Gribble, and M. Johnson, “Evaluation of the FLASH (Flashing Light Animal Sensing Host) System in Nugget Canyon, Wyoming,” Report No. FHWA-WY-01/03F, University of Wyoming, Wyoming Cooperative Fish and Wildlife Research Unit (Laramie, Wy.: July 2001).

MOOSE SIGNS AHEAD
: The moose story comes from Robert Finch, “Moose Signs Ahead,”
Orion,
July–August 2007, p. 7.

“they’ll behave like that”: Monderman’s suspicion of traffic signs was not necessarily a radical stance.
The Manual on Uniform Traffic Control Devices,
the bible of American traffic engineers, itself has a warning about warning signs: “The use of warning signs,” it notes, “should be kept to a minimum as the unnecessary use of warning signs tends to breed disrespect for all signs.”

is cognitive dissonance: Whether a driver actually
gets
the ticket may depend on several factors, as a study by Thomas Stratmann and Michael Makowsky argued. “The farther the residence of a driver from the municipality where the ticket could be contested,” they wrote, “the higher is the likelihood of a speeding fine, and the larger the amount of the fine. The probability of a fine issued by a local officer is higher in towns when constraints on increasing property taxes are binding, the property tax base is lower, and the town is more dependent on revenues from tourism.” From Michael Makowsky and Thomas Stratmann, “Political Economy at Any Speed: What Determines Traffic Citations?,” January 31, 2007; available at
http://ssrn.com/abstract=961967
.

dawn of the car itself: According to the research of one historian, the speed bump was first introduced in Chatham, New Jersey, on April 22, 1906. As reports noted, the paved stone in the road was meant to combat “automobile scorchers,” as speeders were then known. See Peter Applebome, “Making a Molehill Out of a Bump,”
New York Times,
April 19, 2006.

are to violate them: Drivers, it turns out, already tend to treat stop signs like “Slow” signs. A study by Michael DeCesare that looked at a sample of 2,390 vehicles at several intersections in the northeastern United States found that only 14 percent of the group came to a complete stop. Most drivers simply “paused,” and those that did come to a complete stop often did so only because there were already other cars crossing through the intersection. Interestingly, no cars completely violated the stop signs, which implies that stop-sign visibility was not an issue. See “Behavior at Stop Sign Intersections: A Matter of Convenience and Threat of Danger,” paper presented at the Annual Meeting of the Eastern Sociological Society, Boston, 1999.

to make up time: See, for example, Gerald L. Ullman, “Neighborhood Speed Control—U.S. Practices,”
ITE Compendium of Technical Papers
(1996), pp. 111–15, and Richard F. Beaubein, “Controlling Speeds on Residential Streets,”
ITE Journal,
April 1989, pp. 37–39.

time to speed: Reid Ewing, “U.S. Experience with Traffic Calming,”
Institute of Transportation Engineers Journal,
August 1997, p. 30.

to these trips: Crysttal Atkins and Michael Coleman, “Influence of Traffic Calming on Emergency Response Times,”
Institute of Transportation Engineers Journal,
August 1997.

“fatigue of getting upstairs”: Charles Dickens, “Street Accidents,”
All the Year Round,
vol. 8 (1892; repr.), p. 499.

often without supervision: For a good history of the
woonerven,
see Michael Southworth and Eran Ben-Joseph,
Streets and the Shaping of Towns and Cities
(New York: McGraw-Hill, 1996).

acting accordingly in the moment: Interestingly, this idea has had precedents here and there in the history of traffic engineering. In July 1927, the American magazine
Nation’s Traffic
reported on a novel signal system at a four-way intersection that featured white lights instead of the traditional amber. When the lights in all four directions shone white, it signified that cars in all four directions could make left turns. Instead of mayhem during the evening rush hour, the writer reported, “We saw four streams of traffic making left turns at the same time…without the scraping of a fender.” The local police chief made an interesting observation: “We have taught these people to sort of care for themselves.” From Gordon Sessions,
Traffic Devices: Historical Aspects Thereof
(Washington, Institute of Traffic Engineers, 1971), p. 50.

the less we see: This is particularly true at roundabouts. An observational study in Finland found that drivers entering a roundabout were less likely to look to the right and more likely to violate the right-of-way of cyclists crossing to the right. See Heikki Summala and Mikko Rasanen, “Top-Down and Bottom-Up Processes in Driver Behavior at Roundabouts and Crossroads,”
Transportation Human Factors,
vol. 2, no. 1 (2000), pp. 29–37.

around 20 miles per hour: When I presented this theory to Daniel Lieberman, a professor of biological anthropology at Harvard University’s Skeletal Biology Lab, he answered, via e-mail: “I would agree with you that natural selection would have to have permitted the skeleton to survive falls from running and other such natural events, but we were never designed to be hit by 1-ton cars going at 60 MPH (a lot of momentum). But is running the highest natural force a body experiences? Not sure. We also got hit on the head, attacked by saber-tooths, etc. But it is clearly the case that running is a common way to injure ourselves since we are naturally awkward unstable creatures more likely to fall than quadrupeds, and more likely to get injured by a fall (farther to go). So you might indeed be right.”

running a red light: In 2000, for example, more than one thousand people were killed in crashes caused by someone running a red light, according to the Federal Highway Administration. Figure retrieved from
http://safety.fhwa.dot.gov/intersections/comm_rlrfaq.htm
.

people on foot: This raises the question of what happens at intersections without “Walk”/“Don’t Walk” signals. Picture the mayhem as ill-behaved pedestrians cross willy-nilly without being told when to do so. At the time of this writing, it was possible to see this in New York City (although plans were afoot to install pedestrian signals). Simply go to Park Avenue, anywhere from Forty-sixth Street to Fifty-sixth Street. There you will notice that not only are the traffic lights smaller but there are no pedestrian crossing signals (called “ped heads”). For unique structural reasons owing to a commuter train running underneath the street, traffic authorities for years were unable to install the necessary foundation for a standard signal. So are pedestrians hit by cars more frequently at these corners? A five-year “crash map” put together by the city DOT showed that there were no more pedestrians struck in that section of Park Avenue than in the areas immediately to the north and south that had ped heads. This suggests that pedestrians on those blocks were forced to more actively assess the danger posed by cars. The crash map was put together by the New York City Department of Transportation’s Pedestrian Projects office and was supplied to me by Michael King. To fully assess the actual risk faced by pedestrians at those sections of Park Avenue versus other areas, and the reasons why, a comprehensive study would have to be undertaken to determine pedestrian volumes and analyze the causative factors of the crashes. If more pedestrians are struck at those corners, the reason might also have to do with the below-standard traffic signals for vehicles. As Michael Primeggia, the deputy commissioner at the city’s Department of Transportation, noted to me in a conversation,
vehicle
crashes are higher at those corners; particularly “right-angle collisions,” which are often attributed to a car’s failure to stop at a red.

their own green light: This is why engineers often install the “leading pedestrian interval,” or LPI, which gives an “exclusive phase” of a few seconds or so to the walker, to give him a head start and allow him to assert his authority in the crosswalk. This, of course, slows vehicular traffic flow. The most radical example of a pedestrian-only phase is the so-called Barnes dance, named after New York City’s longtime traffic commissioner, in which pedestrians are given the “Walk” signal in both directions and cars in
all
directions must wait. The Barnes dance was not actually invented in New York City, as is often thought, but in Barnes’s previous posting of Denver. After he unveiled an all-way pedestrian phase, a local scribe wrote, “Barnes has made the people so happy they’re dancing in the streets” hence the Barnes dance. See Henry Barnes,
The Man with Red and Green Eyes
(New York: Dutton, 1965), p. 116.

for the health of pedestrians: D. F. Preusser, W. A. Leaf, K. B. Debartla, and R. D. Blomberg,
The Effects of Right-Turn-on-Red on Pedestrians and Bicycle Accidents,
NHTSA-DOT/HS-806/182 (Dunlap and Associates, Darien, Conn.: October 1981).

law than while not: In a study that looked at a year’s worth of pedestrian and bicycle fatalities (1997), drivers were found to be “at least partly culpable” in 71 percent of the cases. See Charles Komanoff, “Killed by Automobile: Death in the Streets in New York City, 1994–1997,” March 1999. In 2004, nearly one-third of all pedestrians killed in New York City were killed in the crosswalk of an intersection. Of all the pedestrian fatalities, the majority (114, or 67.5 percent) were not attributed to any action by the pedestrian, while the categories that reasonably indicate pedestrian blame (“darting, running, or stumbling into road,” “improper crossing of roadway or intersection,” “failure to obey traffic control devices, traffic officers, traffic laws, etc.,” and “walking, playing, working in roadway”) total 48 of 169 fatalities, or roughly 28 percent. See Claire E. McKnight, Kyriacos Mouskos, Camille Kamga, et al.,
NYMTC Pedestrian Safety Study,
Institute for Transportation Systems, City University of New York; prepared for the New York Metropolitan Transportation Council, February 27, 2007.

must navigate several lanes: The undisputed king of marked crosswalk studies is Charles Zegeer, at the University of North Carolina. See Charles V. Zegeer, J. Stewart, and H. Huang,
Safety Effects of Marked Versus Unmarked Crosswalks at Uncontrolled Locations: Executive Summary and Recommended Guidelines, 1996–2001
(Washington, D.C.: Federal Highway Administraion, March 2002); available at
http://www.walkinginfo.org/pdf/r&d/crosswalk_021302.pdf

make things safer: See David R. Ragland and Meghan Fehlig Mitman, “Driver/Pedestrian Understanding and Behavior at Marked and Unmarked Crosswalks,” U.C. Berkeley Traffic Safety Center, Paper UCB-TSC-RR-2007-4, July 1, 2007;
http://repositories.cdlib.org/its/tsc/UCB-TSC-RR-2007-4
. See also Meghan Fehlig Mitman and David R. Ragland, “What They Don’t Know Can Kill Them,” U.C. Berkeley Traffic Safety Center, Paper UCB-TSC-TR-2007-2, April 1, 2007;
http://repositories.cdlib.org/its/tsc/UCB-TSC-TR-2007-2
.

a good thing for pedestrians: Conversely, knowing traffic laws such as right-of-way can be dangerous. A study in Finland that looked at collisions between cars and bicycles found that while only 11 percent of cars reported seeing the bicyclist before the crash, some 68 percent of cyclists reported seeing the car—and 92 percent of those who noticed the car assumed it would yield the right-of-way. See Summala and Rasanen, “Top-Down and Bottom-Up Processes,” op. cit.

of their own safety: One reason for this is the “multiple-threat collision,” in which one driver stops but a driver in the next lane does not, most likely because his view of that pedestrian is blocked. This was described to me in a conversation with Charlie Zegeer at the University of North Carolina, a traffic-safety researcher who has spent more time than anyone studying the problems of getting pedestrians across the road safely. See also Zegeer, Stewart, and Huang,
Safety Effects,
op. cit.

in the face of oncoming traffic: M. Winnet, S. Farmer, J. Anderson, and R. Lockwood, “An Evaluation of the Effect of Removing White Centre Lines,” report prepared for the Wiltshire County Council by CEEMA Ltd. and TRL Limited.

to drive faster: This is an old saw in traffic engineering. In the 1922 book
Good Roads,
for example, author James McConaghie notes that “it has been found that by placing a series of lines on the pavement, dividing the space up into its maximum number of traffic lanes, a greater speeding up of traffic has been the result.” Quoted in Sessions,
Traffic Devices,
p. 104.

insufficiently wide bike lanes: See D. L. Harkey and J. R. Stewart, “Evaluation of Shared-Use Facilities for Bicycles and Motor Vehicles,” Transportation Research Record 1578, Transportation Research Board, Washington, D.C., 1997. For a less scientifically rigorous but no less interesting report, see Pete Ownes, “The Effect of Cycle Lanes on Cyclists’ Road Space,” Warrington Cycle Campaign, October 2005. Other studies have made the point that bicycle lanes reduce the amount of vehicle “displacement”—that is, how much they veer toward the center line or even into the other lane—and that bicycles themselves stay on a straighter path in the presence of lanes. See Bonnie J. Kroll and Melvin R. Ramey, “Effects of Bike Lanes on Driver and Bicyclist Behavior,”
Journal of Transportation Engineering,
vol. 103, no. 2 (March–April 1977), pp. 243–56, and S. R. McHenry and M. J. Wallace,
Evaluation of Wide Curb Lanes as Shared Lane Bicycle Facilities,
Report FHWA/MD-85/06, Maryland Department of Transportation, Baltimore, August 1985.

system was more dangerous!: The Laweiplein information comes from an unpublished study by Jeroen van Doome and Jelmer Herder of the Leeuwarden Technical College. The data is still preliminary and, as in all such studies, it can be difficult to immediately attribute reasons for increases or decreases in crashes. There may still be lingering “novelty effects” in the scheme, as well as a possibility of a “regression to the mean,” whereby statistical entities such as crash statistics possess a natural tendency to fluctuate. More time will be needed to fully assess the scheme. The reader might well wonder whether the safety and traffic improvements made in Drachten could have been achieved by simply converting the space to a conventional roundabout. But the Leeuwarden report notes that the traffic improvements at Drachten outperform what would be expected using modeling for a “conventional roundabout.” Hamilton-Baillie pointed out to me in an e-mail that the geometry of the scheme differs from that of a conventional roundabout: “By narrowing the entrances and exits—they are 6 meters wide—there’s very little flaring. It doesn’t seem to be a problem for traffic to just allow pedestrians and bicycles to just filter through.” The Laweiplein design, he maintains, avoids some of the problems of how to accommodate pedestrians and bicycles, a common criticism of roundabout schemes. On the idea that users thought the system was more dangerous, when it was statistically not, there is evidence that this kind of distortion is not uncommon. In a study conducted on the University of North Carolina at Chapel Hill campus, a group of students were surveyed as to what they thought the most dangerous areas on campus were for pedestrians. Some locations that people thought were “safe” had actually had a number of crashes, even more so than areas they labeled “dangerous.” See R. J. Schneider, R. M. Ryznar, and A. J. Khattak, “An Accident Waiting to Happen: A Spatial Approach to Proactive Pedestrian Planning,”
Accident Analysis & Prevention,
vol. 36, no. 2 (March 2004), pp. 193–211.