In Defense of Traffic Cops

An astute reader named Paul writes with this query: “I work on 34th Street in Manhattan and watch traffic “cops” direct traffic as I walk to my office. As far as I can tell, these officers have nothing but a negative impact; they confuse drivers and pedestrians alike and simply offer no value above what traffic lights do. I understand the idea of having a police presence, say, on a parade day, but why always? Do you have any thoughts on this?”

The first thing to note is that in the world of traffic, every case needs to be taken on its own; so without extensive study of the flows and geometries of that particular intersection, it would be hard to offer concrete analysis. And I’ve not seen hard-core studies analyzing human control versus signalized control (but if anyone has, please let me know).

The second thing is that I’m instinctively sympathetic with traffic cops; after all, the only thing more dangerous than driving in traffic is standing in the middle of it. I must have spent an hour watching the police in Hanoi do their work at a massively tricky crossing, as pictured above. And Paul, you may feel better about the NYPD’s traffic cops after reading this New York Times piece.

But the question raises a number of interesting issues…

Namely, do we even need traffic cops? The first, as an engineer in a major urban DOT told me, is that traffic police are generally used, except in the case of signal failures or special events, at intersections where “driver behavior” is an issue. In other words, people are not obeying the signals, not letting pedestrians cross safely, interfering with pedestrian rights of way, and generally acting like cretins. This is why, for example, one often sees cops near the Holland Tunnel entrance in New York City — left to their own devices, cars (particularly from a certain, ahem, neighboring state) tend to “block the box,” as well as make life miserable for pedestrians. None of this good for throughput, efficiency, or safety.

So the intersections where we tend to see human traffic cops tend to be the worst intersections to begin with (we don’t see them at the empty well-flowing intersections), and seeing them may reinforce the idea that they are somehow making things worse. In fact, things would probably be far worse in their absence. The traffic cop is a sign of our own failure; if we did as we were told, human supervision would not be needed.

In the early 20th century, as traffic signals were being introduced, to phase out human control (New York City got its first traffic cops in 1903), there was a raging debate over which system — man or machine — was more efficient. Burton Marsh, the first full-time urban traffic engineer in the U.S., argued in 1927 that “a competent traffic officer working at his best can usually handle traffic at an individual right-angle corner better than any other means of control of that individual corner yet developed…. the officer can take advantage of variations in the volume of traffic on the two streets and give to each street that proportion of time best suited to it at that minute.”

There’s one major drawback with having traffic cops control intersections, of course, as my DOT contact pointed out: They cannot effectively coordinate with other intersections “down the line.” So they may unwitting send too many vehicles toward a cluttered intersection two blocks away, and not enough toward an empty stretch of road in the other.

There’s one other potential problem, though I’ve not seen this in New York City. In many places — e.g., Moscow — traffic cops are famously corrupt. So rather than making things better they may just be “rent-seeking” as it were. Or, to paraphrase Chicago mayor Richard Daley, they are there “to preserve the existing disorder.” In Mexico City, they’ve tackled this problem in an interesting way: By hiring only women to direct traffic. The “swans,” as they are called, pictured below, are beacons of propriety and a delightful addition to the often mean streets of the D.F.

This entry was posted on Friday, June 13th, 2008 at 8:02 am and is filed under Etc., Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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Traffic Tom Vanderbilt

How We Drive is the companion blog to Tom Vanderbilt’s New York Times bestselling book, Traffic: Why We Drive the Way We Do (and What It Says About Us), published by Alfred A. Knopf in the U.S. and Canada, Penguin in the U.K, and in languages other than English by a number of other fine publishers worldwide.

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Upcoming Talks

April 9, 2008.
California Office of Traffic Safety Summit
San Francisco, CA.

May 19, 2009
University of Minnesota Center for Transportation Studies
Bloomington, MN

June 23, 2009
Driving Assessment 2009
Big Sky, Montana

June 26, 2009
PRI World Congress
Rotterdam, The Netherlands

June 27, 2009
Day of Architecture
Utrecht, The Netherlands

July 13, 2009
Association of Transportation Safety Information Professionals (ATSIP)
Phoenix, AZ.

August 12-14
Texas Department of Transportation “Save a Life Summit”
San Antonio, Texas

September 2, 2009
Governors Highway Safety Association Annual Meeting
Savannah, Georgia

September 11, 2009
Oregon Transportation Summit
Portland, Oregon

October 8
Honda R&D Americas
Raymond, Ohio

October 10-11
INFORMS Roundtable
San Diego, CA

October 21, 2009
California State University-San Bernardino, Leonard Transportation Center
San Bernardino, CA

November 5
Southern New England Planning Association Planning Conference
Uncasville, Connecticut

January 6
Texas Transportation Forum
Austin, TX

January 19
Yale University
(with Donald Shoup; details to come)

Monday, February 22
Yale University School of Architecture
Eero Saarinen Lecture

Friday, March 19
University of Delaware
Delaware Center for Transportation

April 5-7
University of Utah
Salt Lake City
McMurrin Lectureship

April 19
International Bridge, Tunnel and Turnpike Association (Organization Management Workshop)
Austin, Texas

Monday, April 26
Edmonton Traffic Safety Conference
Edmonton, Canada

Monday, June 7
Canadian Association of Road Safety Professionals
Niagara Falls, Ontario

Wednesday, July 6
Fondo de Prevención Vial
Bogotá, Colombia

Tuesday, August 31
Royal Automobile Club
Perth, Australia

Wednesday, September 1
Australasian Road Safety Conference
Canberra, Australia

Wednesday, September 22

Wisconsin Department of Transportation’s
Traffic Incident Management Enhancement Program
Statewide Conference
Wisconsin Dells, WI

Wednesday, October 20
Rutgers University
Center for Advanced Infrastructure and Transportation
Piscataway, NJ

Tuesday, March 8, 2011
Ontario Injury Prevention Resource Centre
Injury Prevention Forum

Monday, May 2
Idaho Public Driver Education Conference
Boise, Idaho

Tuesday, June 2, 2011
California Association of Cities
Costa Mesa, California

Sunday, August 21, 2011
American Association of Motor Vehicle Administrators
Milwaukee, Wisconsin

Wednesday, October 26, 2011
Attitudes: Iniciativa Social de Audi
Madrid, Spain

April 16, 2012
Institute for Sensible Transport Seminar
Gardens Theatre, QUT
Brisbane, Australia

April 17, 2012
Institute for Sensible Transport Seminar
Centennial Plaza, Sydney
Sydney, Australia

April 19, 2012
Institute for Sensible Transport Seminar
Melbourne Town Hall
Melbourne, Australia

January 30, 2013
University of Minnesota City Engineers Association Meeting
Minneapolis, MN

January 31, 2013
Metropolis and Mobile Life
School of Architecture, University of Toronto

February 22, 2013
ISL Engineering
Edmonton, Canada

March 1, 2013
Australian Road Summit
Melbourne, Australia

May 8, 2013
New York State Association of
Transportation Engineers
Rochester, NY

August 18, 2013 “Ingenuity” Conference
San Francisco, CA

September 26, 2013
TransComm 2013
(Meeting of American Association
of State Highway and Transportation
Officials’ Subcommittee on Transportation
Grand Rapids MI



June 2008

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