Too many traffic rules and the tragedy of the commons
There is a stretch of North Glebe Road, in Arlington, Virginia, that epitomizes the American approach to road safety. It’s a sloping curve, beginning on a four-lane divided highway and running down to Chain Bridge, on the Potomac River. Most drivers, absent a speed limit, would probably take the curve at 30 or 35 mph in good weather. But it has a 25-mph speed limit, vigorously enforced. As you approach the curve, a sign with flashing lights suggests slowing further, to 15 mph. A little later, another sign makes the same suggestion. Great! the neighborhood’s more cautious residents might think. »We’re being protected. But I believe policies like this in fact make us all less safe.
I grew up in Great Britain, and over the past five years I’ve split my time between England and the United States. I’ve long found driving in the U.S. to be both annoying and boring. Annoying because of lots of unnecessary waits at stop signs and stoplights, and because of the need to obsess over speed when not waiting. Boring, scenery apart, because to avoid speeding tickets, I feel compelled to set the cruise control on long trips, driving at the same mind-numbing rate, regardless of road conditions.
Relatively recently—these things take a remarkably long time to sink in—I began to notice something else. Often when I return to the U.S. (usually to a suburban area in North Carolina’s Research Triangle), I see a fender bender or two within a few days. Yet I almost never see accidents in the U.K.
This surprised me, since the roads I drive here are generally wider, better marked, and less crowded than in the parts of England that I know best. And so I came to reflect on the mundane details of traffic-control policies in Great Britain and the United States. And I began to think that the American system of traffic control, with its many signs and stops, and with its specific rules tailored to every bend in the road, has had the unintended consequence of causing more accidents than it prevents. Paradoxically, almost every new sign put up in the U.S. probably makes drivers a little safer on the stretch of road it guards. But collectively, the forests of signs along American roadways, and the multitude of rules to look out for, are quite deadly.
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. <a href="http://www.theatlantic.com/doc/200807/traffic">http://www.theatlantic.com/doc/200807/traffic</a>;
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