Traffic

by Tom Vanderbilt

Once humans decided to do anything but walk, once they became “traffic,” they had to learn a whole new way of getting around and getting along.

Instead of complex vocabularies and subtle shifts in facial expression, the language of traffic is reduced—necessarily, for reasons of safety and economy—to a range of basic signals, formal and informal, that convey only the simplest of meanings.

Identity issues seem to trouble the driver alone. Have you ever noticed how passengers rarely seem to get as worked up about these events as you do? Or that they may, in the dreaded case of the “backseat driver,” even question your part in the dispute? This may be because the passenger has a more neutral view. They do not feel that their identity is bound up with the car.

"You are not your car" campaign idea?

Take away human identity and human contact and we act inhuman.

You catch someone’s eye, they let you in, and you wave back, flushed with human warmth.

Many studies have confirmed this: Eye contact greatly increases the chances of gaining cooperation in various experimental games (it worked for Seinfeld’s George, by the way). Curiously, the eyes do not even need to be real. One study showed that the presence of cartoon eyes on a computer screen made people give more money to another unseen player than when the eyes were not present.40 In another study, researchers put photographs of eyes above an “honor system” coffee machine in a university break room.41 The next week, they replaced it with a photograph of flowers. This cycle was repeated for a number of weeks. Consistently, more people made donations on “eye” weeks. The

When subjects looked at a picture that showed a pedestrian or a cyclist, they were more likely to use language that described a person. It somehow seems natural to say “the bicyclist yielded to the car,” while it sounds strange to say “the driver hit the bicycle.”

Eyes are the original traffic signals.

Engineers call the moment when we’re too close to the amber light to stop and yet too far to make it through without catching some of the red phase the “dilemma zone.” And a dilemma it is. Judging by crash rates, more drivers are struck from the rear when they try to stop for the light, but more serious crashes occur when drivers proceed and are hit broadside by a car entering the intersection.

What if there was an eBay-like system of “reputation management” for traffic?

The road is not a private place, and speeding is not a private act.

We overestimate the risks to society and underestimate our own risk.23 It is the other person’s behavior that needs to be controlled, not mine; this reasoning helps contribute to the longstanding gap, concerning evolving technology, between social mores and traffic laws.24 We think stricter laws are a good idea for the people who need them.

After investigating tens of thousands of industrial injuries, he estimated that for every one fatality or major injury in the workplace, there were 29 minor injuries and 300 “near-miss” incidents that led to no injury. He arranged these in the so-called Heinrich’s triangle and argued that the key to avoiding the one event at the top of the triangle lay in tackling the many small events at the bottom.38

The word accident, however, has been sent skittering down a slippery slope, to the point where it seems to provide protective cover for the worst and most negligent driving behaviors.

study led by Peter Chapman and Geoff Underwood at the University of Nottingham in England found that drivers forgot about 80 percent more of their near crashes if they were first asked about them two weeks later than if they were asked at the end of their trip.

“Baker’s law,” named after crash reconstructionist J. Stannard Baker, notes that drivers “tend to explain58 their traffic accidents by reporting circumstances of lowest culpability compatible with credibility”—that is, the most believable story they can get away with.

After poring over forty-three thousand hours of data and more than two million miles of driving, the study found that almost 80 percent of crashes and 65 percent of the near crashes involved drivers who were not paying attention to traffic for up to three seconds before the event.

“A total time of two seconds looking away from the forward roadway is when people start to get in trouble,” explained Sheila “Charlie” Klauer, a researcher at VTTI and the study’s project manager. “That’s when they get to the point when they are starting to lose track of what’s going on in front of them.” The two-second window is not technically related to the “two-second rule” for following distance, but the comparison is instructive.

In general, the average driver looks away from the road for .06 seconds9 every 3.4 seconds.

Researchers talk of the “fifteen-second rule,”11 which indicates the maximum amount of time a driver should spend operating any kind of in-car device, whether navigation or radio, even as they are (at least occasionally) looking at the road. “What we believe is that task time is very important,” Klauer said. “The longer the task time, the more dangerous the task is, and the greater the crash risk.”

The study found that while dialing a cell phone put drivers at a greater crash risk, talking on a cell phone presented only a slightly higher risk than normal driving. “When a driver is talking or listening on their cell phone, at any given moment within that conversation what our odds ratio is telling us is they’re only at a slightly higher crash risk than an alert driver. Statistically speaking, it’s not different,” Klauer said.

“But drivers typically talk on their cell phone for a long period of time. Over that long period of time a lot more crashes and near crashes are more apt to occur. That slight increase in crash risk is starting to add up.”

New drivers, as we have seen, look rather rigidly ahead and near the front of the car, using “foveal” rather than peripheral vision to help them stay in their lane. As drivers get more experienced, they cast their eyes farther out along the road, barely registering the pavement markings.

When you see more of something, you’re more likely to see that thing.

The book Forensic Aspects of Driver Perception and Response gives this example: A parked car that an approaching driver sees 1,000 feet away will double on the retina by the time the driver is 500 feet away. Sounds about right, no? But it will double again in the next 250 feet, and again in the last 250 feet. It is nonlinear.

“Objects in mirror are more complicated than they appear.”

What is actually happening is an example of the phenomenon known as “emergent behavior,” or the formation of complex systems, like cricket bands, that “emerge,” often unexpectedly and unpredictably, from the simple interactions of the individuals. Looking at the swarm as a whole, one might not easily see what is driving the movement. Nor could one necessarily predict by studying the local set of rules guiding each cricket’s behavior—eat thy neighbor and avoid being eaten by thy neighbor—that this would all end up as a tight swarm.

You’re not stuck in a traffic jam. You are the traffic jam. —advertisement in Germany

But as horse trams came along, then electric trams, then subways, and, finally, the car, the city kept growing, by roughly an amount proportional to the speed increase of the new commuting technology—but always such that the center of the city was, roughly, thirty minutes away for most people.

Who’s making these trips? Mostly women. This is the kind of social reality that traffic patterns lay on the table: Even though women make up nearly half the workforce, and their commutes are growing increasingly close in time and distance to men’s, they’re still doing a larger share of the household activities that, back in the Leave It to Beaver days, they may have had the whole day to complete12 (and, as Rosenbloom points out, 85 percent of single parents are women).

In fact, women make roughly double the number of what are called “serve-passenger” trips—that is, they’re taking someone somewhere that they themselves do not need to be. All these trips are squeezed together to and from work in a process called “trip chaining.” And because women, as a whole, leave later for work than men, they tend to travel right smack-dab in the peak hours of congestion (and even more so in the afternoon peak hours, which is partially why those tend to be worse). What’s more, these kinds of trips are made on the kinds of local streets, with lots of signals and required turning movements, that are least equipped to handle heavy traffic flows.

Where it was once the overwhelming norm for children to walk to school, today only about 15 percent do.17 Parents on the “school run” are thought to boost traffic on the roads by some 30 percent.18

Driving to work alone, which is what nearly nine out of ten Americans do, is still, on average, about one and a half minutes faster than the average time for all other travel methods.

One study that looked at the working poor found that those with a car were able to get around three times more quickly than those without one.

Research has shown that people tend to underestimate the time it will take to get somewhere in a car and overestimate the time it will take to walk somewhere.

The Nobel Prize–winning economist Herbert Simon has suggested, in a seminal theory he called “satisficing” (a mix of satisfying and suffice), that because it is so hard for humans to always behave in the optimal way, we tend to make choices that leave us not with the “best” result but a result that is “good enough.”

Cars spend about 95 percent of their time parked.

on an average day cars in one fifteen-block section drove some 3,600 miles—more than the width of the entire country—searching for a spot.

The more time one spends looking for parking, of course, the greater chance one has to get in a crash, which then creates even more congestion. Interestingly, parking itself, according to some studies, is responsible for almost one-fifth of all urban traffic collisions.

As drivers, we are constantly creating what economists call, in the thorny language of economics, “uninternalized externalities.” This means that you are not feeling the pain you are causing others.

The bigger intersections grow, the less efficient they become. Adding a second left-turn lane, for instance, means that, for safety reasons, “permissive” (or on the green) left turns can no longer be allowed. Only “protected” left turns (on the green arrow) will be allowed.

Congestion charging, in cities like London and Stockholm, has been shown to work because it forces people to make a decision about—and gives them a precise benchmark against which to measure—whether a given trip is “worth it.”

Imagine there are two routes. Drivers are told that one is five minutes faster. Everyone shifts to that route. By the time the information is updated, the route that everyone got on is now five minutes slower. The other road now becomes faster, but it quickly succumbs to the same problem.

Faced with roads that had overnight theoretically become more dangerous, Swedes were behaving differently. Studies of drivers showed they were less likely to overtake another when a car was approaching in the oncoming lane, while pedestrians were looking for longer gaps in the traffic before choosing to cross. Had Sweden’s roads actually become more dangerous? They were the same roads, after all, even if drivers were driving on a new side. What had changed was that the roads felt less safe to Swedish drivers, and they seemed to react with more caution.

Intersections are crash magnets—in the United States, 50 percent of all road crashes occur at intersections.

total crashes dropped nearly 40 percent, while injury crashes dropped 76 percent and fatal crashes by about 90 percent.

(roundabouts)

Tests of what researchers call “expectancy” routinely show that it takes drivers longer to respond to something they do not expect than something they do expect.

One rough rule of thumb for highways is that drivers should not drive for more than a minute without having a bit of curve.

roadside rumble strips. The results were striking. After they were installed on the Pennsylvania Turnpike, run-off-road crashes dropped 70 percent in the period studied.

when a situation feels safe, that is precisely when you should feel on guard. Most crashes, after all, happen on dry roads, on clear, sunny days, to sober drivers.