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Abstract
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Economists and ecologists sometimes speak of the "tragedy of the commons" — the way rational individual actions can collectively reduce the common good when resources are limited. How this applies to traffic safety may not be obvious. It's easy to understand that although it pays the selfish herdsman to add one more sheep to common grazing land, the result may be overgrazing, and less for everyone. But what is the limited resource, the commons, in the case of driving? It's attention. Attending to a sign competes with attending to the road. The more you look for signs, for police, and at your speedometer, the less attentive you will be to traffic conditions. The limits on attention are much more severe than most people imagine. And it takes only a momentary lapse, at the wrong time, to cause a serious accident.
What matters most for road safety? The quality of the roads themselves? The engineering of the cars that travel them? The speed limit? The answer may be "none of the above." In 1949, a British statistician named R. J. Smeed, who would go on to become the first professor of traffic studies at University College London, proposed a now-eponymous law. Smeed had looked at data on traffic fatalities in many different countries, over many years. He found that deaths per year could be predicted fairly accurately by a formula that involved just two factors: the number of people and the number of cars.
Smeed's Law has worked less well since the mid-1960s; traffic deaths have been somewhat reduced by engineering features such as seat belts and air bags. But technical improvements generally matter less than you might expect, because they affect driver behavior. It's called "risk compensation": as cars become safer, drivers tend to take more risks. Psychological factors, in other words, appear to play a huge role in road safety, and they often undercut well-intentioned safety initiatives.
So what am I suggesting — abolishing signs and rules? A traffic free-for-all? Actually, I wouldn't be the first to suggest that. A few European towns and neighborhoods — Drachten in Holland, fashionable Kensington High Street in London, Prince Charles's village of Poundbury, and a few others — have even gone ahead and tried it. They've taken the apparently drastic step of eliminating traffic control more or less completely in a few high-traffic and pedestrian-dense areas. The intention is to create environments in which everyone is more focused, more cautious, and more considerate. Stop signs, stoplights, even sidewalks are mostly gone. The results, by all accounts, have been excellent: pedestrian accidents have been reduced by 40 percent or more in some places, and traffic flows no more slowly than before.
What I propose is more modest: the adoption of something like the British traffic system, which is free of many of the problems that plague American roads. One British alternative to the stop sign is just a dashed line on the pavement, right in front of the driver. It actually means "yield," not "stop"; it tells the driver which road has the right of way. Another alternative is the roundabout. Roundabouts in the U.S. are typically large. But as drivers get used to them — as they have in the U.K. over the past three or four decades — they can be made smaller and smaller. A "miniroundabout" in the U.K. is essentially just a large white dot in the middle of the intersection. In this form, it amounts to no more than an instruction to give way to traffic coming from the right (that would be the left over here, of course, since the Brits drive on the left).
As these examples indicate, traffic signs in the U.K. are often on the road itself, where the driver should be looking. And most right-of-way signs are informational: there are almost no mandatory stops in the U.K. (The dominant motive in the U.S. traffic-control community seems to be distrust, and policies are usually designed to control drivers and reduce their discretion. The British system puts more responsibility on the drivers themselves.) |