This article in Sunday’s Washington Post, penned by New America Foundation fellow Joel Kotkin, is definitely thought provoking. In the wake of terrorist attacks in London and New York, Kotkin argues that the single most important challenge facing modern cities is providing basic security to their citizens. To wit …

While modern cities are a long way from extinction, it’s only by acknowledging the primacy of security — and addressing it in the most aggressive manner — that they will be able to survive and thrive in this new century, in which they already face the challenge of a telecommunications revolution that is undermining their traditional monopoly on information and culture, and draining their populations.

Wiith memories of 9/11 still fresh, perhaps it’s natural that people should question whether cities are really safe. Terrorism is, quite obviously, a serious problem; and central cities have proven to be ready targets.

Still, I think that the article’s emphasis on terrorism per se reveals an interesting and broader cultural bias about risk. There are certain kinds of risks that our culture fears more than others. Some hazards — say, the threat of random violence, whether by ordinary criminals or by terrorists — seem intolerable, and society demands a concerted effort to put a stop to them. Others — say, traffic accidents — we generally shrug off, and accept as part of the unavoidable background of modern life.

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But sometimes the "unavoidable" risks are far more hazardous, and every bit as avoidable, as the ones on which we focus our attention.

At least two peer-reviewed studies (PDFs here and here) have looked at how urban form affects the risk of dying in a vehicle collision. Both studies concluded that people who live in low-density, sprawling neighborhoods face a much greater risk of dying in a car accident than people who live downtown. In New York City, the risk of dying in a collision, either as a pedestrian or a motor vehicle occupant, was only a fourth to a seventh as high as it was for people living in the suburban outskirts of Cleveland, Toledo, Kansas City, or Greensboro, North Carolina. The reason: people who live in sprawling suburbs drive more than people in the urban core, and accident risk is fairly proportional to the distance that people drive.

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Likewise, combining the risk of collision and crime, counties on the urban fringe were often more dangerous than those at the city center (though older, inner-ring suburbs were often the safest of all). Apparently, the added risk of dying in a car accident in car-dependent, outer-ring suburbs more than counterbalanced the (slightly) elevated risk of dying at the hands of a stranger with a gun in the inner city.

This idea — that, looking comprehensively across a number of risks, central cities are safer than bucolic outer-ring suburbs — runs counter to intuition. From Kotkin’s article …

Attempts by mayors in these cities to be "hip and cool" have not turned them around, in large part because they are still perceived as unsafe. Baltimore’s Mayor Martin O’Malley has cultivated an image of coolness for himself and encouraged other "cool" people, including singles and gays, to add to his city’s "creative class." Yet as one Baltimore resident suggested to me recently: "What’s the point of being hip and cool if you’re dead?"

That sentiment might be reasonable enough if it were really true; but the numbers suggest that, as a general rule, it’s not. (Baltimore, of course, may be an exception to the rule — its murder rate is high enough that it’s a bit riskier than the average city.)

Of course, terrorism may throw a monkey wrench into these sorts of calculations; one serious attack at a city center can more than make up for the risk of dying in a car crash at the outskirts of town. Worse, the risk of a terrorist attack in any given city is quite literally unknowable; it may be quite high, or it could be close to nil. Which makes it very hard to say with any certainty how risky it might be to live in a modern city.

But still, it may be that big cities suffer from an image problem: their problem isn’t so much actual security as it is perceived security. As a general rule, center cities may, in fact, be fairly safe; but in an era of heightened attention to crime terrorist threats, they may not feel that way.

Now, Kotkin’s article doesn’t claim that the threat of terrorism has, by itself, enticed large numbers of people to flee center cities. Most central city populations have declined in the US and Europe over the past 50 years or so, but many other demographic and cultural forces are at play here. Still, he finds plenty of historical examples in which security threats eventually turned even big cities into ghost towns — and suggests that the same thing may be happening again.

He may, of course, be right. But before you hitch up your wagons and head for the hills, it’s worth keeping in mind that — as appalling as the prospect of crime and terrorism may be — there are other, less heralded but equally real risks associated with lie at the edge of town.