Archive for the ‘Traffic Signals’ Category

The Bird, the Wave, and the Shaka

My latest Slate column is up, and the subject is the informal language of the road (and yes I know about the Australian ‘waggling pinkie,’ but for editing reasons, etc., it got cut). For space reasons I also didn’t get into the whole gamut of bicyclist/motorcyclist/pedestrian gestures — though I remember at one Brooklyn crosswalk I was turning right and a person about to enter the crosswalk did an elaborate bow/sweep of the hand to urge me through, to which my reply was to try to apologize for violating the right of way. Then there was a secondary round of strange gestures in response to the first. And then, of course, the driver behind me honked.

Posted on Tuesday, February 9th, 2010 at 1:34 pm by: Tom Vanderbilt
Comments Off on The Bird, the Wave, and the Shaka. Click here to leave a comment.

Shopping Timing

In the book I discuss special “Sabbath timing” patterns for traffic signals in Los Angeles.

From the Washington Business Journal comes word of new patterns for a more secular holiday: Black Friday:

The Virginia Department of Transportation will alter traffic signals at 14 shopping centers in Northern Virginia to accommodate the increase in shoppers on Black Friday and during the holiday season.

Using traffic data from previous years, VDOT will implement time- and location-specific signal timing at 188 intersections.

The timing changes are intended to minimize backups near shopping centers and maximize traffic flow around them.

Posted on Wednesday, November 25th, 2009 at 6:20 pm by: Tom Vanderbilt
Comments Off on Shopping Timing. Click here to leave a comment.

Left on White

Reader Francisco sends along, via Shorpy, an image sure to delight the ranks of historical traffic signal enthusiasts (that’s the Washington, D.C. traffic director inspecting the hardware circa 1926)

Posted on Thursday, July 30th, 2009 at 11:56 am by: Tom Vanderbilt
Comments Off on Left on White. Click here to leave a comment.

Problems With Signalized Intersections, Continued

A problem with traffic signals you’ve probably not thought much about: The new LED lights (which consume less energy) tend not to melt the obscuring snow that accumulates on them.

Posted on Monday, July 27th, 2009 at 9:55 am by: Tom Vanderbilt
Comments Off on Problems With Signalized Intersections, Continued. Click here to leave a comment.

Red Yellow Green

In Traffic I make a passing mention of the evolution of traffic light sequences:

Others wanted the yellow light shown before the signal was changing to red and before it was changing from red back to green (which one sees today in Denmark, among other places, but nowhere in North America).

Reader Claire writes in to note that she remembers this sequence being used in the U.S.:

I distinctly remember passing through signals of this type on arterial streets in Chicago between 1977 – 1983. They were mostly located west of the L tracks on arterial streets like Belmont, Armitage, Fullerton, Devon, and Ashland.

Now, I didn’t say they were never used in the U.S., just that they aren’t anymore — although I may be wrong here and I’d be curious to see an example. She helpfully points us to Willis Lamm’s Traffic Signal page, which contains video examples of these “really funky signal phases.”

I’ve seen international studies on the potential problems with the red-amber-green phase, but haven’t really heard or read an account of why these phases vanished in the U.S. (though I’m sure the information is out there, in some back issue of the ITE Journal). I can imagine there are pedestrian issues, not to mention intersection clearance issues. And given that hardly anyone drives a manual shift in the U.S., one of the perceived virtues of that system is now largely lost here, like an old piece of slang no one uses anymore.

Posted on Tuesday, July 14th, 2009 at 12:01 pm by: Tom Vanderbilt
Comments Off on Red Yellow Green. Click here to leave a comment.

A Passing Fancy

I’m fascinated by all the curious would-be traffic safety devices lingering in dusty patent offices around the world, a collection of better brake lights, more evocative horns, elaborate safety harnesses, etc., that have never made it onto the road (for better or worse).

I came across the one above, recently, via Modern Mechanix. It’s evidently meant as a way to make passing other vehicles on two-lane roads a safer proposition.

But a few problems come to mind:

1.) As with all new signals, there is the problem that many drivers don’t use the existing signals they have.

2.) What if a driver is distracted or doesn’t care to respond to your request for passing clearance?

3.) Are we really to trust the driver ahead to tell us if it’s safe to pass?

4.) Does the driver ahead want to be held liable if it turned out it wasn’t safe to pass?

Posted on Thursday, June 18th, 2009 at 11:03 am by: Tom Vanderbilt
Comments Off on A Passing Fancy. Click here to leave a comment.

Bad News for Traffic Signal Manufacturers

From the Times of London, a story that seems “ripped from the pages” of Traffic.

The always good transpo correspondent Ben Webster asks:

What would happen if traffic lights were suddenly switched off? Would there be gridlock or would the queues of frustrated drivers miraculously disappear?

People in London are about to find out the answer in Britain’s first test of the theory that removing lights will cure congestion.

For six months, lights at up to seven junctions in Ealing will be concealed by bags and drivers will be left to negotiate their way across by establishing eye contact with pedestrians and other motorists.

The reason for the trial was pure accident:

Ealing found evidence to support its theory when the lights failed one day at a busy junction and traffic flowed better than before. Councillors have approved a report which recommended that they “experimentally remove signals since experience of signal failure showed that junction worked well.”

Of course, careful attention will have to paid to safety results, particularly with pedestrians (the piece refers to some new mid-block crossings but one has to entertain the idea that these treatments may reduce pedestrian’s perception of safety and thus, potentially, one’s inclination to walk). The one day of outage could have represented a novelty effect. But the interesting thing about these novel treatments is that they are often done with much more care and concern than the standard “out of the book” approach that is applied automatically.

Ealing Council believes that, far from improving the flow of traffic, lights cause delays and may even increase road danger. Drivers race towards green lights to make it across before they turn red. Confidence that they have right of way lulls them into a false sense of security, meaning that they fail to anticipate hazards coming from the side. The council hopes that drivers will learn to co-operate, crossing junctions on a first-come first-served basis rather than obeying robotic signals that have no sense of where people are waiting.

(Horn honk to Prashanth)

Posted on Saturday, May 2nd, 2009 at 3:22 pm by: Tom Vanderbilt
Comments Off on Bad News for Traffic Signal Manufacturers. Click here to leave a comment.

‘…and I want to paint it black…’

Speaking of traffic lights, apparently there’s a movement afoot to paint them black.

Reports The Birmingham News:

“Several states along the West Coast’s Sunbelt: California, Arizona and Nevada, use traffic signals encased in black housing to reduce glare, especially at sunrise or sunset. The black paint absorbs the sunlight instead of reflecting it back into the eyes of the driver.”

And a refreshingly frank assessment from the city’s engineer:

Birmingham Traffic Engineer Greg Dawkins said the black signal heads look better. “I found no compelling reason to keep the yellow, except that is the way it has always been done,” he said.

Posted on Thursday, March 5th, 2009 at 6:52 am by: Tom Vanderbilt
Comments Off on ‘…and I want to paint it black…’. Click here to leave a comment.

Green Wave Blues

One of my personal urban pet peeves is that the traffic signals on a street like New York’s Fifth Avenue, on which a majority of users are pedestrians, seemed timed in such a way to interfere as much as possible with smooth ambulatory progress. Seriously, I feel like I have to stop at every single light on Fifth.

From the invaluable Streetfilms comes a look at what would happen if a street like Valencia in San Francisco had its signals timed such that cyclists had a green wave. What about cars, you ask? Isn’t that anti-car-ism? Well, actually, as San Francisco Streetsblog points out: “Recently, the San Francisco Municipal Transportation Agency (MTA) found that during peak commute times vehicles run more efficiently when signals are timed at the speeds they actually travel during congestion — 12 to 15 mph — rather than the current 25 mph.” Not to mention that cyclist signal compliance rates will inevitably rise. On streets to which you’re trying to attract cycles, why not offer the carrot instead of merely the stick? Synchronization, in a grid city, has its natural limits but it’s certainly worth favoring certain modes on particular streets.

I often find some of the most hazardous urban driving behavior to be people accelerating between lights, or emerging from a pack of congestion. The question is how to get drivers to stick to speeds that are lower overall, but actually promote smoother, more fuel-efficient driving. ISA (intelligent speed adaptation) is probably the most far-reaching tool, but in some ways a political non-starter in the U.S. (for now, at least). I suspect that merely telling drivers through signage that the only way to get a row of greens is to drive 15 or 20 mph will somehow not work (the average driver is an incredibly opportunistic, short-range planner, only concerned with getting to the next red light as fast as possible).

Posted on Monday, February 2nd, 2009 at 4:24 pm by: Tom Vanderbilt
Comments Off on Green Wave Blues. Click here to leave a comment.

Traffic Light Neurosis

When I came across this line on the website for Time, for a moment I assumed it must be another article talking about Shared Space, Hans Monderman, etc.:

“Since it scrapped its traffic light system four years ago, busy, industrial Bayonne, N.J. has had a substantial decrease in traffic mishaps.”

Then I looked at the date of the article: 1938.

I’m not sure what Bayonne replaced its lights with —anyone know? — perhaps early traffic circles.

In any case, the rest of the article has some enduring implications for contemporary traffic:

“No scientist has explained why. But last week, in the Journal of the American Medical Association, Cincinnati Physician Howard D. Fabing examined the behavior of the average motorist, found that traffic lights caused conditioned reflexes which made him as dithery as one of Russian Physiologist I.P. Pavlov’s famous third-degreed dogs.

One of Professor Pavlov’s dogs was taught that a circular light flashed on a screen meant food, that an elliptical light meant none. Then the ellipse was gradually rounded out until it was nearly circular, but no food. This psychological double-cross sent the dog into a nervous state called traumatic neurosis, from which he had to be rescued by rest and daily rectal instillations of bromides. An obedient motorist is conditioned to stop at a red light, to proceed at a green. But Dr. Fabing’s research marked the green as a treacherous come-on, since often just when a motorist steps on the accelerator the green light changes to red, so that his right foot must jump for the brake. Soon most motorists develop what Dr. Fabing calls an “anxiety neurosis in miniature,” mainly centred in an uncertain right foot, but with other noticeable effects. On himself, Dr. Fabing noted “a quickening of my pulse by 25 beats … a pilomotor [hair-on-end] response on my forearms, a dryness of the mouth, a sudden excessive sweating of the palms a feeling of epigastric distress.”

Not willing to suggest abolition of traffic lights, which most safety experts agree are necessary in heavy traffic, Dr. Fabing called attention to several patented, non-confusing systems. His recommendation: a clock-dial light with a rotating hand swinging from a green section at the top to a yellow caution light at the quarter-hour position, to a red section at the bottom, to another yellow caution light at the three-quarter-hour position— the hand always showing by its position how much green or red time remains.”

Posted on Monday, September 29th, 2008 at 12:09 pm by: Tom Vanderbilt
Comments Off on Traffic Light Neurosis. Click here to leave a comment.

Audi’s Dumb New Smart Technology

Do you remember how, in the early days of the personal computer, you would constantly hear of all the amazing things you could do with it, such wondrous tasks as “balancing your checkbook”? In other words, you were being asked to spend a significant sum to do something that would more easily and efficiently be done on the cheapest calculator.

I get something of that vibe — I’ll call it “egregious technology” — from a new Audi project called “Travolution” (thanks Jalopnik), which the company describes as such:

“Communications modules built into each traffic light are able to send messages to cars in the vicinity, alerting them to the time remaining until their next green phase. The car’s onboard system is then able to calculate the speed which the driver must maintain in order to pass through the light during this green phase, and displays this via the Multi Media Interface display.”

In other words, the traffic lights send a signal to the approaching Audi, which then gives the driver an approach speed that will allow them to fluidly sail through the intersection, avoiding fuel-wasting stops and starts.

I’m skeptical of this for a few reasons. The first is that my 2001 Volvo already happens to have this technology. What’s more, it cost me nothing to add it.

What’s the wonder device? My brain. Partially because I like to drive in a way that maximizes fuel efficiency, and partially because I don’t get much of a kick at idling at traffic lights, I tend to slow down ahead of time if I see I’m approaching an intersection whose traffic signal is red (conversely, and who doesn’t do this, if I see the green is “fading,” based on flashing ped signals, I will speed up, within reason).

I’m constantly astounded how often, in New York City, drivers — particularly taxi drivers — often blaze past me, only to find themselves lingering at the light (maybe it’s because we’re wired to focus on short-term gains). Then, even though I was going slower to begin with, but because I haven’t had to make a complete stop, I typically drive right past them.

Avoiding unnecessary stopping and acceleration is one of the main precepts of “eco-driving” or “hyper-miling,” but it’s really just a function of being an alert, thinking driver (and some studies have noted the connection between fuel efficient driving and safe driving).

This leads me to my second big complaint with Audi’s system. Not only is it asking the driver to take their eyes off the road to look at a gauge to get information they could more or less discern by looking ahead, at the road, it presumably wouldn’t know things like the length of the queue of vehicles waiting at the light (unless, perhaps, they were all Audis) — so any stated approach speed might be completely inappropriate given the necessary start-up and clearance time of all the other vehicles. The simple fact of being given an approach speed for the intersection might induce some kind of “automatic” thinking, in which a driver may focus on maintaining the correct speed as their key task rather scanning the intersection (where close to half of all crashes occur) — in the way drivers can focus too much on the light itself rather than, say, vehicles that haven’t cleared the intersection for some reason.

Of course, being given the correct approach speed for hitting the green isn’t much help if you’re asked to approach at five miles an hour because the light is backed up with traffic. That’s why I suspect the money (not sure what Audi’s communicative lights would cost) would be better spent on lights that could talk to each other. Which we already have, of course, in some places — but even these need human help once in a while.

Posted on Thursday, September 25th, 2008 at 1:32 pm by: Tom Vanderbilt
Comments Off on Audi’s Dumb New Smart Technology. Click here to leave a comment.

“The Whole Village Has Become More Human”

An alert reader sends along some more coverage, this time by Isabelle de Pommereau in the Christian Science Monitor, of Bohmte, a German village that has become another waypoint in the evolving “Shared Space” movement (I was in the town a few years ago, for a Shared Space conference, but haven’t been back since things were changed). The town, like many, felt overwhelmed by the 13,000 vehicles per day coursing through its small center.

Readers of the book and blog by now may well know the drill:

“But this summer the town reworked its downtown thoroughfare, not only scrapping the traffic lights but also tearing down the curbs and erasing marked crosswalks. The busiest part of the main street turned into a “naked” square shared equally by bikes, pedestrians, cars, and trucks. Now, there is only one rule: Always give way to the person on the right.”

Bohmte is providing yet another surprising example of the types of environments in which this sort of thing can be done: “What’s revolutionary about Bohmte is that it took off its signs on a state highway with a lot of traffic,” says Heiner Monheim, a traffic management expert at the University of Trier, speaking at a recent European conference on sign-free towns convened here. Beyond that, Monheim says, the model’s real legacy is to have brought people closer to “rediscovering and appreciating cities not only as traffic places but also as human, social places.”

But I was also struck in particular by this passage:

“Two months into the experiment, ‘Instead of thinking, ‘It’s going to be red, I need to give gas, people have to slow down, to look to the right and the left, to be considerate,’ says Ms. Rubcic… The bonus? Town people recognize they have become a bit closer to one another. ‘The whole village has become more human. We look at each other, we greet each other,’ she says.”

Posted on Tuesday, September 16th, 2008 at 3:23 pm by: Tom Vanderbilt
Comments Off on “The Whole Village Has Become More Human”. Click here to leave a comment.

Of Tea Kettles and Traffic Lights

Reading Stefan Klein’s hugely entertaining and informative Time: A User’s Guide yesterday, I came across this traffic-related tidbit:

“Where do you have a longer wait: At a red light, when you’ve just missed the green — or in your kitchen, waiting for an electric kettle to boil water for a cup of tea? If you think that boiling water takes more time, you’re mistaken: both require an average of ninety seconds.”

This comparison intrigued me for several reasons. The first is that one rarely sees “traffic time” compared to other moments of time from everyday life. What other mundane acts of life could theoretically be performed in the time stuck at the lights?

The second is that very fact that we wouldn’t think of the time we spend at a light as being equal to waiting for tea; this in itself reminded me of studies I had seen in which people underestimated the amount of time it would take to drive somewhere, and overestimated the amount of time it would take by another mode. Traffic is a very time-skewing activity in general. When we’re moving along at a good clip, we tend not to notice any time signals (except for “on the hour” announcements on radio and the like); when we’re stuck in heavy traffic, aware of every vehicle passing us, we’re more aware to minor moments of progress and change and thus, as Klein argues, these trivial things add up to “a perceived time that seems much longer than what our watches tell us.” Which is why watched kettles, of course, take longer to boil.

Posted on Tuesday, September 2nd, 2008 at 7:01 am by: Tom Vanderbilt
Comments Off on Of Tea Kettles and Traffic Lights. Click here to leave a comment.

Self-Organized Traffic Flow

One of the oft-revisited themes in the book is that individual actors in traffic don’t often have an idea of what might be best for traffic as a whole. In a great piece in the New Scientist (sub required), “Why Complex Systems Do Better Without Us,” Mark Buchanan (whose book The Social Atom is high on my reading list), writing about the traffic physicist Dirk Helbing, makes the following point:

“Although the behaviour of individuals is often simple, the collective patterns to which it leads can be counter-intuitive, making common sense a faulty guide to what might happen. For example, it is generally true that traffic jams become more likely as traffic density increases. It’s not always the case, though, as Helbing’s group has shown.

Consider a two-lane road carrying both cars and trucks, where the cars are moving faster on average. At low traffic densities, the cars have plenty of space to overtake and can easily pass the trucks. As the traffic density increases, drivers find it more difficult to overtake because other vehicles are in the way. However, evidence from simulations and real traffic flows shows that at a critical density of traffic, the obstruction to lane-changing begins to have a beneficial effect. Because drivers tend to stay in one lane, they disturb the flow of traffic less, leading to a higher total throughput of vehicles.”

Another interesting strand in the piece is the notion that allowing traffic lights to control themselves would improve traffic flow. Instead of set timing patterns or even merely “synchronization,” the lights judge conditions for themselves and make constant adjustments (this is essentially the high-tech version of Hans Monderman’s “bottom-up” traffic scheme in the Netherlands). This is one of the next frontiers of traffic, and I’ve had described to me fascinating systems employing “genetic algorithms” for things ramp meter lights — the ramp meters would in essence keep learning over generations of traffic flow, evolving into smarter systems.

Of course, the new light schemes run the risk of not making sense to the individual driver, as Buchanan notes: “Nonetheless, the behaviour of the lights doesn’t generally fit with human notions of what ought to be efficient. “How long lights stay green is unpredictable,” says Lämmer. Yet the average journey times go down and become more predictable.”

The piece includes what may come to be a mantra: “Being in control, it seems, may increasingly demand being a little out of control.”

Posted on Friday, August 29th, 2008 at 4:45 am by: Tom Vanderbilt
Comments Off on Self-Organized Traffic Flow. Click here to leave a comment.

The Men With the Horns

Like Aaron Naparstek, I don’t much like car horns. Particularly in New York, where they seem to be used — almost always inappropriately — at a higher frequency than comparatively honkless cities like Los Angeles.

But lately there’s one place I’ve been enjoying the cacophony of automobile horns: My stereo. I missed this when it came out last year, but now Por Por: Honk Horn Music of Ghana, by The La Drivers Union Por Por Group, has been on heavy rotation. As recorded and documented by noted ethno-musicographer Steven Feld, and published by Smithsonian’s Folkways, the album documents an obscure musical form borne from the daily rhythms of Ghanaian traffic life, as experienced by drivers of the vehicles known as “tro-tros.” It’s exuberant, infectious, and unlike the guy behind you as the light turns to green, surprisingly pleasant to the ears. (more…)

Posted on Friday, June 27th, 2008 at 8:17 am by: Tom Vanderbilt
Comments Off on The Men With the Horns. Click here to leave a comment.
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.

Please send tips, news, research papers, links, photos (bad road signs, outrageous bumper stickers, spectacularly awful acts of driving or parking or anything traffic-related), or ideas for my Transport column to me at:

For publicity inquiries, please contact Kate Runde at Vintage:

For editorial inquiries, please contact Zoe Pagnamenta at The Zoe Pagnamenta Agency:

For speaking engagement inquiries, please contact
Kim Thornton at the Random House Speakers Bureau:

Order Traffic from:

Amazon | B&N | Borders
Random House | Powell’s

U.S. Paperback UK Paperback
Traffic UK
Drive-on-the-left types can order the book from

For UK publicity enquiries please contact Rosie Glaisher at Penguin.

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



March 2023

No, you probably won be compensated one million dollars; however, with the right blend of negotiating skills and patience, your efforts will be substantially rewarded!I have seen up to forty thousand dollars added to starting compensation through diligent negotiations. It is a way to significantly raise your standard of living and sense of self, simply by