Free Traffic by Tom Vanderbilt

more time watching those vehicles zip by in the next lane. To make matters worse, the researchers found that the closer a driver drove to the car in front of him, and the more glances he made to the next lane, the worse the illusion seemed.
    Something else might also be helping to create the illusion. Drivers spend most of their time—anywhere from 80 percent to over 90 percent, studies have found—looking at the forward roadway. This includes, of course, the adjacent lane; estimates are that for every two glances we make at our own lane, we make one glance at the next lane—simply so we can actually stay in our lane. This means we are highly aware of vehicles passing us. We spend only about 6 percent of our driving time looking in the rearview mirror. In other words, we’re much more aware of what is passing us than what we have passed.
    The fact that we spend more time seeing losses than gains while driving in congestion plays perfectly into a well-known psychological theory called “loss aversion.” Any number of experiments have shown that humans register losses more powerfully than gains. Our brains even seem rigged to be more sensitive to loss. In what psychologist Daniel Kahneman has called the “endowment affect,” once people have been given something, they are instantly more hesitant to give it up.
    Do you remember the childlike glee you felt the last time you found a parking spot at the mall on a crowded day? You may have left the spot with a certain reluctance, particularly if someone else was waiting for it. Studies have shown that people take longer to leave a parking spot when another driver is waiting, even though they predict they will not. It’s as if the space suddenly becomes more valuable once another person wants it. In strict terms it does, even though it is no longer of intrinsic value to the person leaving it. This sensitivity to loss might also help explain the late-merger dilemma described in the Prologue. What really triggers the decision to change lanes is not so much the coolly rational assessment of underused transportation capacity but the fact that people kept passing while the early mergers stood still. The late merger’s gain is perceived as the early merger’s loss.
    But what’s the harm in merely changing lanes, anyway? One study, by the National Highway Traffic Safety Administration, found that almost 10 percent of all crashes involved lane changes. How many of those lane changes were necessary, and how many were discretionary? Do we really understand what is involved in the choices we are making? It is this last question that was at the heart of Redelmeier and Tibshirani’s lane-changing study, for Redelmeier, a soft-spoken, sober doctor who spends a third of his time seeing patients at the Sunnybrook Health Sciences Centre in Toronto, has a privileged window on to the consequences of the decisions we make while driving.
    “I mostly look at individuals that get seriously damaged in the aftermath of a crash,” he told me in his office. “For many of them, their lives are ruined forever. For many of them, there’s also this tremendous sense of remorse or chagrin—you know, if only they had behaved slightly differently, they would have never ended up in the hospital. There’s a real element of almost counterfactual thinking that goes on in the aftermath of a crash. When someone comes down with pancreatic cancer there’s a lot of suffering that’s going on, but they usually don’t start second-guessing themselves about how things could have been done differently in order to avoid this terrible predicament, whereas with motor vehicle crashes it’s a very strong theme. That got me thinking how complicated driving is.”
    We may be doing things in traffic for reasons we do not even understand as we are acting. But how we can resist things like the next-lane-is-faster illusion? Redelmeier suggests, if not completely seriously, that we might feel better if we spent more time