Traffic: Why We Drive the Way We Do

The New World army ant (Eciton burchelli) lives in colonies that can number over one million inhabitants. Each morning, by the hundreds of thousands, the ants stream out into the world along several wide corridors to hunt for food, which they must then carry back to their nest. It’s a simple enough task, but all this coming and going presents a logistical problem: The ants weighed down with food move more slowly then the unencumbered outbound ants, which threatens to snarl the whole operation.

It took thousands of years, but the ants—nearly blind, by the way—have evolved a solution. They lay a trail of pheromones that other ants follow where the trail is densest, and as a result each corridor organizes itself into three lanes: a middle lane, occupied by the slow ants, flanked by a pair of lanes for the speedier ants headed in the opposite direction. Every now and then the ants crash into each other, causing a momentary delay, but on the whole it is a marvel of coordination and efficiency.

Not for nothing do we say that from airplane windows cars look like ants. At first glance the army ant’s daily commute bears a striking resemblance to those in Los Angeles, Houston, and New York. But as journalist Tom Vanderbilt suggests in his absorbing new book, “Traffic: Why We Drive the Way We Do (and What it Says about Us),” humans in fact have a lot to learn from insects. We have the sharpest brains and most advanced road infrastructure of any species on earth, yet we continue to be baffled by driving and traffic. As a longtime New York City traffic commissioner once observed, as the “technical problems” of traffic “become more automatic,” the “people problems become more surrealistic.” It is these surreal “people problems” to which Vanderbilt turns his attention.

The formula behind “Traffic”—as well as the book’s breezy style and pop-culture references—will be familiar to anyone who has read Blink, Freakonomics, or the innumerable world-in-a-grain-of-sand books that followed on the heels of Mark Kurlansky’s Cod. Touching on neuroscience, psychology, economics, and urban planning, Vanderbilt leads us through a series of case studies that gently inform us, despite what we know in our hearts, that we are not all traffic experts. He takes us to the Los Angeles traffic control center on Oscar night, uses the lines at Disneyland’s Space Mountain to explain the pros and cons of congestion pricing, and introduces us to a Stanford University team that has discovered how difficult it is to program a robot to drive a car.

Programming humans to drive is nearly as difficult, it turns out, as the act of driving is fraught with optical and neurological blind spots. The speed of our vehicles has outpaced the speed of evolution, such that our brains and eyes, accustomed to traveling at much slower speeds, deceive us repeatedly. One study cited by Vanderbilt found that at 30 mph drivers are presented with roughly 1,320 pieces of information a minute—and we have a distinct fondness for misinterpreting them. We have trouble gauging the speed of an oncoming car at a distance, for example, and in a phenomenon known as “inattentional blindness,” we tend to overlook the objects we don’t expect to see—the very objects that pose the most danger. In ways large and small, we misjudge risk.

At the same time, we lack the solidarity of the army ant. Humans in cars are “‘selfish commuters’ driving in a noncooperative network,” Vanderbilt suggests, and the stress of driving also appears to magnify human emotion and weakness. As anyone who has ever ridden in a car can testify, the anonymity we feel on the road—largely due to the lack of eye contact, some experts speculate—can lead to antisocial, narcissistic behavior that we would never dream of on foot. The paradox of traffic, according to Vanderbilt, is that it reveals both our biological limitations and our baser impulses. “We act too human,” he writes, “we do not act human enough.”

To make matters worse, our “pheromones”—the dotted lines, signs, and HOV lanes we use to mark our paths—often fail us. With the help of experts and the latest research, Vanderbilt gleefully debunks some of the more common road-related fallacies. Simply adding more lanes (or roads) doesn’t ease traffic, for instance, since more drivers, acting in their own self-interest, will take advantage of the quicker commute and ultimately ruin it for everyone. Nor do brighter signs and marked crosswalks necessarily make us safer. Vanderbilt points to the Dutch woonerven (literally “living yard”), a space without sidewalks or traffic signs that, counterintuitively, produces fewer accidents than a traditional intersection. (To demonstrate the effectiveness of this “traffic calming,” a half-mad Dutch traffic scientist walks backwards through a rotary with his eyes closed as cars crawl around him, inadvertently demonstrating the forbearance of the Dutch as well.) Vanderbilt even disputes the long-held notion that so-called “late mergers,” the drivers in a narrowing road who zip into a lane at the last moment, are sociopaths; he argues that they actually make the road more efficient by maximizing its capacity.

This is compelling stuff, but the book’s predictable format (anecdote-study-quote, anecdote-study-quote) can make “Traffic” seem at times like the longest Slate article ever written. (Vanderbilt has contributed to that magazine, as well as Wired, I.D., and numerous other publications.) While the Braess paradox, the Leibowitz hypothesis, and motion parallax make for interesting reading, Vanderbilt ultimately sheds little light on the nagging questions and hunches that for most drivers build up mile after mile. Why do minor accidents on I-95 in Connecticut cause nine-mile backups? Why are most (fill in gender/ethnic group/other stereotype here) bad drivers? Why do Americans struggle with the concept, embraced by Europeans, that the left-hand lane is reserved for crisp, decisive passing, not cell-phone conversations?

The answers to these questions would seem to be alluringly complex. Driving, especially in traffic, is one of the few activities on earth (along with sex and perhaps real estate) that incorporates money, politics, status, psychology, instinct, training, and reflexes. It therefore has the potential—and here Vanderbilt’s instincts are right on the money—to tell us more about ourselves than just about anything. Traffic is, as Vanderbilt puts it, “a sort of secret window onto the inner heart of a place, a form of cultural expression as vital as language, dress, or music.”

But when Vanderbilt, in a chapter entitled “How Traffic Explains the World,” attempts to arrive at a broader explanation for why we drive the way we do, he raises more questions than he answers. In all, he files traffic reports from more than a half-dozen countries, and the comparisons are intriguing. The “motorized maelstrom” of Delhi and the chaotic intersections of Shanghai seem quite similar, as one might expect, but Vanderbilt also reveals that Italy and Germany, practically neighbors, have dramatically different driving cultures. (In Italy, the humor columnist Dave Barry once remarked, “there is only one traffic law, which is that no driver may ever be behind any other driver.”) Vanderbilt lets the opportunity to examine what separates Italian from German from Chinese traffic fall by the wayside, however. After some passing speculation about the connection between anarchic Chinese driving and Confucianism (which cultivates fealty to one’s family, rather than laws), Vanderbilt chalks up the differences to “norms” before launching into a readable but ultimately unconvincing Freakonomics-esque analysis of corruption and traffic fatality rates. A more ambitious book might have attempted to tease apart the factors that underlie those driving norms.

One has the sense that Vanderbilt is neglecting the best material. There is something about driving that lends itself to allegory, and “Traffic” is thus most satisfying when read between the lines (so to speak). The comparisons of human traffic to insect behavior are some of the book’s most fascinating sections, but when the ant expert points out that the efficiency of commuting worker ants is possible only because they, unlike dog-eat-dog humans, “all labor for the queen,” Vanderbilt brushes past the implications. Elsewhere, a German physicist philosophizes on traffic reports and real-time traffic data. “What you want is for people to do certain things,” he says, in, one likes to imagine, a flat Teutonic accent. “Telling them the whole truth is not the best way.”

These throwaway lines contain enough material to fill another, different kind of book. What can we infer from the fact that homogenous worker ants represent, in the words of Vanderbilt’s researcher, “the pinnacle of traffic organization in the actual world”? What does it mean that the Dutch were the first to remove traffic signs? What does poverty—or colonialism—have to do with traffic norms in India? Again, why do Americans insist on blocking the passing lane? We are left to wonder, since Vanderbilt leaves these side streets largely unexplored.

“Traffic” contains enough nuggets of information to stake you at dinner parties through the holidays, but those readers hoping for a kind of unified field theory for traffic and driving, an insight that will finally unlock the hidden connection between driving, society, and the human condition, will be disappointed. “Traffic” will indeed make you look at on-ramps and traffic jams in a new light, but it will not help explain the collision of psychic and cultural forces that seems to occur behind the wheel. Who has not peered deep into his soul in gridlock? That is a somewhat different subject, to be fair, one that will likely require a latter-day Dostoevsky or Kafka.