Fewer Traffic Signs, Better Safety?

Imagine what would happen if you took down road signs and traffic signals. More accidents would surely result, or at least significant confusion and slower traffic. Or would it? The surprising thing is that a number of cities around the world have actually done this, and experienced dramatic declines in traffic accidents.

The idea is based on an urban design philosophy known as "shared space." When drivers, pedestrians and bicyclists are forced to develop their own natural ways of interacting with each other, goes the thinking, they work out better social behaviors than the rule-driven behaviors dictated by professional traffic engineers. This does not mean an abandonment of design considerations, but rather a commitment to the larger public space designs instead of overly prescriptive traffic control devices such as traffic lights, signs and road markings.

The Dutch town of Drachten adopted this "unsafe is safe" approach in 2007 and found that casualties at one junction dropped from thirty-six over the previous four years to only two in the two years following the removal of traffic lights. Traffic jams no longer occur in the town’s main junction, which handles 22,000 cars a day. The town is “Verkeersbordvrij,” meaning “free of traffic signs.” (I am grateful to Jonathan Zittrain’s reference to Drachten’s experiment in his new book, The Future of the Internet and How to Stop It, and to Wikipedia for its account of "shared space." )

What caught my eye was the explanation of why the elimination of strict rules can, in some circumstances, produce better outcomes. Hans Monderman, one of the pioneers of the shared-space approach, said, “When you don’t exactly know who has right of way, you tend to seek eye contact with other road users….You automatically reduce your speed, you have contact with other people and you take greater care.”

The idea is to return public spaces to people in order to encourage them to take greater personal responsibility. Monderman explained, "We’re losing our capacity for socially responsible behavior….The greater the number of prescriptions, the more people’s sense of personal responsibility dwindles."

Who could have thought that the wisdom of Lao-tsu, in the Tao Te Ching, could be applied to traffic safety engineering?

Stop trying to control.

The more prohibitions you have,

If you don’t trust the people,

Jonathan Zittrain mentions the shared-space design philosophy as a way to explain the success of Wikipedia. I would extend the principle to many other commons -- water management, lobster harvesting, free software projects, scientific database commons, and much else. We naturally have greater respect for rules that we have had some role in formulating -- and a willingness to punish those who misbehave — than we have for rules that have been imposed upon us by some higher authority.

All of this is not to say that the world will necessarily or naturally self-organize itself. A larger "meta-design" is often needed to enable social behaviors to emerge and sustain themselves. One way that this occurs, according to Wikipedia’s entry on "shared space," is by having a "fine-meshed slow network" and a "larger-meshed fast network."

The slow network, which is the subject of the shared space treatment, is characterized as the street network which make public space vital and accessible. On the slow network, motor traffic is welcomed as a guest, but has to adapt to certain social norms of behavior. The layout of the road must make this clear. The fast or supra-traffic network, which allows traffic to reach destinations quickly, and which is designed using traditional traffic engineering methodologies, is essential if the slow network is to function properly.

Surely the "shared space" philosophy in traffic engineering has some larger lessons for our reflexive faith in law at the expense of social norms. We tend to rely too much on the power of law -- and minimize the importance of on-the-ground social norms. It is akin to the conventional liberal focus on constitutional test cases and regulation when sometimes the more important goal should be organizing a social movement.

On the other hand, libertarians and conservatives tend to celebrate social voluntarism and local control while failing to admit such approaches are often no substitute for strong, well-enforced laws. A number of conservative ideologues, in their attempts to thwart safety regulation, for example, argue that mandatory seat belts, motorcycle helmets and even anti-lock blocks simply encourage people to drive faster and more recklessly. By that logic, we should put sharp knives on dashboards so that people will drive safely.

I revel in the counter-intuitive success of Verkeersbordvrij because it honors the role each of us have as social agents. That said, let’s face it: law is often indispensable for maintaining certain shared ethical norms. And cultures differ. What works in Holland may not work in Colorado. But who could quarrel with experiments in empowering people to develop their own ways of resolving collective concerns, whether it is driving across town or editing an online encyclopedia?