15 October 2006


In a comment on an old post on Brazilian urban design, TheWayOfTheGun points us to a fascinating Wired article about traffic engineer Hans Monderman. His philosophy: remove signs and road markings and rely on the geometry of the roadway to calm traffic.

This is the hip new thing in traffic engineering, and apparently it works. Again, I've been reading City Comforts, and David Sucher advocates curvy roads and roundabouts, arguing that it's not slow driving speed that frustrates people, it's signs telling them to drive slower than the road is designed to accomodate — and then having to start and stop in the process. Steady driving at slower speeds is calming.

Monderman clearly has the knack for traffic design. The Wired article talks about an intersection he did.

We pass by the performing arts center, and suddenly, there it is: the Intersection. It's the confluence of two busy two-lane roads that handle 20,000 cars a day, plus thousands of bicyclists and pedestrians. Several years ago, Monderman ripped out all the traditional instruments used by traffic engineers to influence driver behavior—traffic lights, road markings, and some pedestrian crossings—and in their place created a roundabout, or traffic circle. The circle is remarkable for what it doesn't contain: signs or signals telling drivers how fast to go, who has the right-of-way, or how to behave. There are no lane markers or curbs separating street and sidewalk, so it's unclear exactly where the car zone ends and the pedestrian zone begins. To an approaching driver, the intersection is utterly ambiguous — and that's the point.

Monderman and I stand in silence by the side of the road a few minutes, watching the stream of motorists, cyclists, and pedestrians make their way through the circle, a giant concrete mixing bowl of transport. Somehow it all works. The drivers slow to gauge the intentions of crossing bicyclists and walkers. Negotiations over right-of-way are made through fleeting eye contact. Remarkably, traffic moves smoothly around the circle with hardly a brake screeching, horn honking, or obscene gesture. “I love it!” Monderman says at last. “Pedestrians and cyclists used to avoid this place, but now, as you see, the cars look out for the cyclists, the cyclists look out for the pedestrians, and everyone looks out for each other. You can't expect traffic signs and street markings to encourage that sort of behavior. You have to build it into the design of the road.”

That elegance of subtly encouraging folks to do the right thing is a hallmark of good design in any field. And the knack for getting the sum of small details right to do that is the defining characteristic of a good designer.

I've talked about Maya Lin before, as an example of this principle. For the Vietnam Veteran's Memorial, Lin was very insistent on using stone that could be polished to be reflective. She knew that for the memorial to work, you had to see your face reflected behind the names.

A good designer studies principles and successful examples, but that's not enough to make a good designer. It also requires that knack for cooking up the elements just right. This is one of the baffling things about both art and craft. It feels the same to create good art and bad art. The artist, or the craftsperson, is certain.

Monderman tucks his hands behind his back and begins to walk into the square —backward—straight into traffic, without being able to see oncoming vehicles. A stream of motorists, bicyclists, and pedestrians ease around him, instinctively yielding to a man with the courage of his convictions.

Which is not to say that certainty is a sign that a designer is talented. But uncertainty is always a sign that a designer doesn't have the knack.

Update: Another article on Monderman, and a little observation about intersections without stoplights:

The key thing is that basically everyone drives slowly and steadily rather than in a stop-and-go manner. Stop-and-go turns out to be less a way of increasing safety than a way of maximizing the value of vehicles with high top speeds (i.e., automobiles) rather than slower vehicles (bicycles, scooters, motorcycles). So filling your city with signalized intersections turns out to be a kind of backdoor subsidy to automobile ownership.

A Spiegel article about Monderman hits another point about the psychology of driving:

“The many rules strip us of the most important thing: the ability to be considerate. We're losing our capacity for socially responsible behavior,” says Dutch traffic guru Hans Monderman, one of the project's co-founders. “The greater the number of prescriptions, the more people's sense of personal responsibility dwindles.”

Monderman could be on to something. Germany has 648 valid traffic symbols. The inner cities are crowded with a colorful thicket of metal signs. Don't park over here, watch out for passing deer over there, make sure you don't skid. The forest of signs is growing ever denser. Some 20 million traffic signs have already been set up all over the country.

Psychologists have long revealed the senselessness of such exaggerated regulation. About 70 percent of traffic signs are ignored by drivers. What's more, the glut of prohibitions is tantamount to treating the driver like a child and it also foments resentment. He may stop in front of the crosswalk, but that only makes him feel justified in preventing pedestrians from crossing the street on every other occasion. Every traffic light baits him with the promise of making it over the crossing while the light is still yellow.

The result is that drivers find themselves enclosed by a corset of prescriptions, so that they develop a kind of tunnel vision: They're constantly in search of their own advantage, and their good manners go out the window.

The new traffic model's advocates believe the only way out of this vicious circle is to give drivers more liberty and encourage them to take responsibility for themselves. They demand streets like those during the Middle Ages, when horse-drawn chariots, handcarts and people scurried about in a completely unregulated fashion. The new model's proponents envision today's drivers and pedestrians blending into a colorful and peaceful traffic stream.

It may sound like chaos, but it's only the lesson drawn from one of the insights of traffic psychology: Drivers will force the accelerator down ruthlessly only in situations where everything has been fully regulated. Where the situation is unclear, they're forced to drive more carefully and cautiously.

1 comment:

Kate said...

The roundabout is a "staple" in Cyprus. I did not see one accident or even "near miss" the entire time we were there. It really does seem to work well.