Review: Why We Drive the Way We Do (and What It Says About Us)

David C. Holzman
by David C. Holzman

It’s not that people are unpredictable. They are predictable. But they frequently behave counterintuitively, a phenomenon that has given rise to the field of behavioral economics. Like economists, engineers have traditionally ignored psychology. Traffic: Why We Drive the Way We Do (and What It Says About Us), is a 300-odd page romp into what scientists are learning about how traffic really works now that they are accounting for the human element. Take “passive safety.” It’s long been the philosophy behind efforts to make driving safer. Reduce driver demands by simplifying the driving environment, and protect people from getting hurt in crashes—rather than teaching skillful driving. After all, it’s easier to engineer safety than change behavior. But too much safety lulls the driver into complacency.


Driving down Orlando’s US Highway 50 with author Tom Vanderbilt, Dan Burden, a traffic eminence, notes that trees have been eliminated, and the sidewalk pushed so far back from the street as to be in “another world,” all to relieve drivers of hazards and distractions. Nonetheless, this stretch is the 12th deadliest road in America.

Yet, nearby on 50, where lanes and clear zones are narrower, and dangerous “fixed objects”–poles and trees–remain, but where traffic is otherwise completely comparable, a fatality hasn’t occurred in five years. “The hazards [are] the safety device,” Vanderbilt writes. “Drivers left with little room for error seemed quite capable of not making errors.”

That concept extends to rotaries, which not only move traffic considerably more quickly than standard stoplight intersections, but are safer, even though–or rather because–drivers have to compensate for uncertainty by driving more carefully. This is the rationale behind the famous Dutch traffic engineer Hans Monderman’s counterintuitively safe blending of the worlds of pedestrians, cyclists, and motorists on narrow streets.

Oddly, Vanderbilt ignores this logic for highway speeds, an issue that has arisen as politicians use safety as an additional excuse to promote a new double nickel to address skyrocketing oil prices and climate change. Vanderbilt marshals considerable evidence to argue that slower is always safer, but he doesn’t dig into special cases.

Boosting the speed limit on Indiana interstates from 65-70 mph, which raised average speeds by more than 3 mph, did not lead to more injuries or deaths, according to a recent study. Investigator Fred Mannering of Purdue University largely credits reduced speed variance, and adds that greater alertness may also have played a role.

The take-the-human-out-of-the-equation approach combined with labor saving devices–slushboxes, radar cruise control, etc–leads yuppies to think they can multitask safely behind the wheel. Vanderbilt cites various studies to explain why they won’t get away with it. Attention capacity is limited, and easily breached. One of several examples: “pedestrians using mobile devices walked more slowly and were less able to interact with the device, pausing occasionally to “sample the environment”,” Vanderbilt writes. And stuff happens so quickly in traffic that more than two seconds’ inattention boosts the risk of collision 19-fold.

There’s much more. Vanderbilt dissects the frustrations of getting stuck in slow traffic. Anxiety, uncertainty, and boredom all slow time, as does the sense–oft illusory–that other lanes are moving quicker. He reports that driving is safest in the least corrupt countries. And he explains why adding more highways or lanes has diminishing returns, and why traffic increases to fill new capacity, through “latent demand.”

When a strike removed 9,000 trucks from the roads near Los Angeles, within a few days the traffic was as bad as ever. (Nonetheless, more than several years after completion of the Big Dig, it still takes me only 25-30 minutes–reliably–to drive to Boston’s Logan Airport, as compared to 45 minutes to an hour in the old days.)

There is no easy way to ease traffic, short of moving to the Great Plains or the Great Basin. But understanding its flows may make it slightly less intolerable.

David C. Holzman
David C. Holzman

I'm a freelance journalist covering science, medicine, and automobiles.

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  • Nrd515 Nrd515 on Jun 11, 2010

    Driver training and writing people up for tailgating would be money better spent over trying to make the roads "safer". The moronocity out there is just amazing. I drive to work on US 23/I475 every night, and home on surface streets in the morning. It's a toss up which route has more morons on it. There seems to be a real trend where people seem to have no idea how to merge onto a freeway. They creep up there, or they are doing great up to the point where they would actually merge, and they chicken out and slam on the brakes. Another, really scary thing is slamming the brakes on whenever an OSP car is seen. I have been nearly rear ended a couple of times recently when this happened and I had to slam my brakes on to keep from hitting the clown in front of me who stopped for no reason at all. Last week, a car in the next lane slammed into an F-150 who had to hit his brakes to keep from hitting a woman who slammed her brakes on when she came over the overpass and saw an OSP car ON THE SHOULDER OF THE OTHER SIDE OF THE HIGHWAY writing a guy up. I asked the trooper I saw at Bob Evans later on about it, and he said the slamming on brake thing isn't new in itself, but the coming to a stop or near stop is, and it's almost to the point he's waiting to hear a crash or a near one, every time he writes someone up in the daytime. It doesn't seem to happen as much at night. Yesterday, on the way to work, there was some idiot in a silver Honda driving like he was in "Ronin", making crazy lane changes, tailgating and flashing his bluish tinted aftermarket lamps (I got the pleasure of getting flashed right after I merged at 75 MPH!) blinding the people he's trying to pass. I tried to call 911 on him, but my phone wigged out (again), and he was out of sight and probably into Michigan by the time I had shut my phone off and turned it back on again. This same guy drives the same way everytime I see the car. I can't read the plate, he's got one of those plastic covers on his rear plate and it's all fogged up. He needs to be taken off the road for a while. On the way home, this 25 year old guy is behind me, about 3 feet behind me, for almost 15 minutes. I wished I was driving an old beater, or my old Dodge Power Wagon, which had a 4" pipe full of concrete as a rear bumper. If I would have been, I would have slammed on the brakes, just to wreck him. He's talking on the phone, smoking, and playing with his car stereo (As far as I could tell), all while driving 45 MPH. I finally got to a 4 lane road and was able to get into the other lane. When I pulled up next to him at the next light, I decided to say something, even though I know it's not a good idea. I honked and he looked at me and I rolled the window down, and told him he needed to back off and not ride up people's asses like he did, and he was lucky I wasn't driving something I didn't care about, or his car would be behind a tow truck. I could tell he had no idea what he did wrong. I just got the hell away from him. But a friend's video of his recent trip to Boston made me happy I live in the Toledo area. His trip to Italy last year made Boston look good though.

  • Russycle Russycle on Jun 18, 2010

    Bizarre...I happened to run across this article last night, found it and the comments interesting. Opened my newspaper this morning, there's a story about a local resident killed while walking along Highway 50 in Florida....and I'm in Oregon. Apparently an SUV just left the highway and crushed him. Wonder if it was on the "safe" or "dangerous" section of the highway.

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