Traffic: Why We Drive the Way We Do (and What It Says About Us) - Tom Vanderbilt (2008)
Epilogue. Driving Lessons
Before embarking on this book, I hadn’t thought much about driving since first learning to do it and acquiring my license on the, ahem, second try. Since then, I’ve logged a few hundred thousand miles or so, had several minor crashes (“accidents” if you must, though both were easily my fault, because of careless behavior whose specifics shall be withheld), and dropped by to the Department of Motor Vehicles every decade or so to glance at an eye chart and get renewed by a grumpy clerk. I mostly just got behind the wheel, fussed over the radio, and hit the road with a mixture of anxiety and wonder: anxiety over the danger of it all, the crumpled cars on the roadside, the shockingly poor behavior, the nervous way people say, “Drive safely” as you leave them; and a simultaneous sense of wonder that we’re all able to move about at high speeds, in such great numbers, with such fluidity.
After spending a long time sifting through the theories and science of traffic, I wondered if there was not still more to be learned about driving a car. I thought, Why not go to those people who, for sport and for a living, drive cars at the absolute limits, in conditions that make even the most frantic traffic seem sedentary? What could race-car drivers have to teach civilians about driving? And so one morning I found myself hunched into one of those small chairs with an attached desk, part of a group including gum-chewing teens and graying sixtysomethings, in a brightly lit classroom at the Bob Bondurant School of High Performance Driving, just south of Phoenix. At the front of the class stood Les Betchner, jauntily tanned and with spiky blond hair, a sometime stock-car racer who exuded the easy patter and ridiculously innate competence that just seems the birthright of people like airline pilots and sports instructors.
Drivers, as you well know by now, tend to self-enhance. We are thin-skinned about our sense of driving competence. One is loath to admit, at age forty, that there are new things to be learned. And yet this is just what was happening. “A steering wheel doesn’t do much,” Betchner was saying. “You steer with the pedals.” What? I snapped to attention. Steer with the pedals? He was PowerPointing his way through the problems of skidding around corners. Racers loathe skidding, not because it means they are out of control but because they are, as they say, “scrubbing speed.” “We never want to slide,” Betchner said. “That’s the slow way around the track.”
As you may recall from your driving lessons, there are two kinds of corner skids, an “understeer skid” and an “oversteer skid.” On the race track they say an understeer skid means it’s your front end that’s smacking the guardrail, while in an oversteer skid your rear end hits first. Despite the word steer, steering is only part of knowing how to react to and correct for under- or oversteer situations. It can often hurt more than help. “Add a bunch of steering, you go right off the road,” Betchner said. “Physics is now part of your life.”
The real key to skid control, he explained, is “weight transfer.” In an understeer skid, the car’s front wheels have lost traction. Attempting to steer will only make matters worse. Braking shifts weight to the front and adds grip. In an oversteer skid, meanwhile, the rear of the car has lost traction and wants to pass the front. The slip angle, or the difference between the direction the tires are pointed and the direction they are actually moving, is greater in the rear tires than the front. The first step in taming the rear wheels is, essentially, taking the turn more widely. So instead of moving the steering wheel in the direction of the turn, increasing the slip angle, you must “steer into the skid”—move the steering wheel in the direction the rear of the car is moving. Many of us know what “steer into the skid” means without really knowing what it means. The larger problem, Betchner pointed out, is that no one is ever taught what to do next. He queried the room. There were some half-mumbled answers. No two seemed to be the same. “Pray?” someone joked.
The answer is the opposite of what you might expect: Hit the gas. “When in doubt, flat out,” instructed Betchner. (Actually, he added, you want to add just a touch of throttle input.) The natural instinct, of course, is to hit the brakes. The problem is that this shifts weight to the front end of the car—exactly where you don’t want it to be. As your car dips toward the front end, you’re helping your rear wheels lose their already tenuous grip on the road. They need every ounce of pressure they can get. Then there is the final problem. You can’t just keep steering into a skid. “That’s where we find ourselves getting into trouble,” said Mike McGovern, another longtime Bondurant instructor. “We do that first part well, but when the car hooks up and comes back to straight, we hold the steering. We don’t unwind it. We’re telling the car to turn again, and that’s when you get into a secondary skid.” This is another somewhat counterintuitive lesson: To fully reassert control, you need to relinquish the steering, letting the pull of the realigned tires do the work as the steering wheel spins through your hands.
Another lesson that seemed rather obvious—but proved curiously powerful once tried out on the test track—was the Bondurant mantra “Look where you want to go.” This recalls the “moth effect” phenomenon and brings up a chicken-and-egg sort of problem that vision researchers still debate: Do we automatically travel in the direction we are looking, or do we first search for a target destination and then keep looking in that direction to maintain our course? Do we drive where we look or look where we drive? The former, arguably: As one study found, “there is a systematic and reliable tendency for [drivers] to follow their direction of gaze with their direction of travel, in many cases without the conscious awareness of doing so at all.”
This might seem rather academic and of little concern to you, but consider what happens when a car suddenly pulls out in front of you as you’re speeding down a rural road. If you “target fixate,” as the Bondurant instructors call it—that is, look at the car that pulled out instead of where you need to be to evade the crash—do you have less chance of avoiding the accident? Does your “gaze eccentricity,” as vision people call it, negatively affect your ability to steer away from the obstacle?
The science is still inconclusive, but on the Bondurant “skid pad” the effectiveness of the racer’s maxim “Look where you want to go” was made strikingly clear. I was driving a Pontiac Grand Prix equipped with outrigger wheels attached to the back end. At the flick of a switch, the instructor could raise the car to simulate a skid at much faster speeds. As I repeatedly drove in loops and practiced getting out of oversteer skids, I found I corrected more easily by concentrating not on the giant barrier of rubber tires I was sliding toward (admittedly not an easy thing to ignore) but on that place around the corner where I wanted to be.
It would be easy to dismiss the school, with its fleets of Corvettes, its acrid tang of burned rubber and exhaust, its looping Grand Prix-style track, as a playground for the unhinged libidinal fantasies of people normally shackled by the world of everyday driving. Indeed, there was a heavy midlife-crisis vibe about the place. And yet there were myriad moments where I thought to myself, Why didn’t I know this before?
“Driver’s ed taught you how to get a license,” Bob Bondurant told me in his office, his ever-present dog Rusty, a Queensland heeler, panting nearby. “It didn’t teach you skid control or evasive emergency maneuvers.” In 1967, Bondurant’s promising racing career was cut short when the steering arm on his McLaren Mk II broke at 150 miles per hour, propelling him into an embankment that sent his car “as high as a telephone pole.” Since then, he has been teaching people like Clint Eastwood and James Garner how to handle a car. This is not how most of us learn, of course. “The driver-ed guy might be your English teacher,” Bondurant said. He or she knows as much about driving, he implied, as the average person. And mostly, this is fine. Despite the prediction from Karl Benz, the founder of the Mercedes-Benz company, that the global car market would be limited because only a relative few would possess the skills needed to drive, most of us, as Bondurant said, “just plunk our butt down in the seat and drive down the road.”
Indeed, there is a strong argument against the idea that we should emulate the actions of people like race-car drivers in everyday life. In a well-known (but not since repeated) study conducted in the 1970s, researchers from the Insurance Institute for Highway Safety looked into the off-course driving records of a pool of stock-car drivers. These drivers were no doubt capable of handling themselves around tight turns, no doubt superior at anticipating their moves ahead of time, no doubt possessed faster reaction times than ordinary people. How had they actually performed on the road, off the track? They’d not only gotten more traffic tickets (which we would expect given their penchant for risk) but they’d also had more crashes than the average driver. Racers possess superior control of a car, to be sure, but control alone does not win races. They also need that ineffable something within that tells them to push just slightly beyond their limits, and the limits of every other driver, to win. As Mario Andretti put it, “If everything seems under control, you’re just not going fast enough.” They had, one might argue, put themselves into positions in which their skills were not always enough to keep them out of trouble.
In everyday traffic, “good driving” has little to do with cornering ability or navigating between tight packs of high-speed vehicles. It’s more a matter of just following the rules, staying awake, and not hitting anyone. This is not to say that racing cannot teach us things about everyday driving. Racers, Betchner said, sit erect and close, alert for feedback signals that can be felt in the pedals and steering wheel. The typical driver’s posture, however, is terrible. “Most of us sit back, the ‘Detroit lean,’” he said. “The car communication is horrible.” Some drivers, he lamented, sit so far back they cannot reliably depress the brake pedal far enough to activate the antilock system. Or consider vision, the sense that is supposed to account for 90 percent of our driving activity. The racer’s dictum that you should always be looking ahead to where you want to go next, which helps them speed through turns, is just as apt for something as prosaic as navigating an intersection. One reason for the high numbers of pedestrians struck in the crosswalk by vehicles turning is that drivers are simply not looking in the right place; they may be concentrating on making the corner itself as they turn (particularly if they are on a cell phone or otherwise distracted), rather than on what the result of their turn will be. In racing, this slows you down. In real life, it means you might hit someone.
Everyday driving also presents those moments for which nothing in our previous experience can have adequately prepared us: the oncoming car crossing the line, the sudden obstacle in the headlights. At Bondurant, I went through repeated drills—for instance, driving a car as fast as I could toward a set of cones, hitting the brakes hard enough to activate the antilock system (something that actually took me several tries), and then steering off into a small lane marked by different cones. I was struck by just how much control of the vehicle I had under full braking. The ABS did not help me stop any more quickly; indeed, another exercise, one that involved steering into one of three lanes at the last moment at the command of a signal, drummed home the idea that certain crashes, inevitable if I had braked, could be rather easily avoided by simply steering. It did, however, open my eyes to the ability one has, with ABS, to stop and steer at the same time.
That may seem, like the other lessons at Bondurant, rather common knowledge, but the wealth of evidence derived from studies of what drivers actually do in the critical moments of emergency situations suggests otherwise. First, drivers are actually quite reluctant to steer when an obstacle suddenly looms in front of them. The majority of drivers brake first and steer last, if at all, even in tests where steering is physically the only way to avoid a crash. This may be because steering might seem to put the driver in an even more precarious position, or it may be because the driver is unaware of the way the car is capable of handling, or it may simply be a form of “operant conditioning”—pressing our brakes, like staying in our lane, has so often been the right thing to do in everyday driving, it begins to seem the only thing to do. But research has also shown that drivers rarely activate the brakes to their full power. Other studies have demonstrated that when steering is attempted, the maneuver tends to be in the same direction the obstacle is moving, which hints that drivers are not “looking where they want to go” (and moving in that direction) but are focused instead on the obstacle to be avoided.
Whether or not the “muscle memory” of my evasive actions on the test course can be sustained over years of uneventful driving is an open question. The major problem is that so many things can go wrong in traffic that it would be impossible to teach, much less remember, appropriate responses for each scenario. Add to this the problem that because these events are unexpected, our reaction times are slowed; the emotional duress of a potential crash might even further slow our reactions—sometimes, studies have shown, to the point where we do nothing.
Then there is the shifting, dynamic nature of traffic itself. It is sometimes impossible to say what a “correct” evasive maneuver would be in the moment of trying to avoid another driver, as it could be canceled out by an unexpected countermove by that other driver. In one trial, forty-nine drivers were put in a driving simulator at Daimler-Benz. As they approached an intersection, a car that had been stopped on the crossroad suddenly accelerated into the intersection, then halted in the drivers’ lane. The reaction time of every driver was sufficient, in theory, to avoid a crash. But only ten of forty-nine did. Part of the problem is that they had only time enough to react to the presence of the approaching car, and not enough time to fully discern what the intruding car was going to do. It was less about a correct maneuver than a roll of the dice.
Whether advanced driver training helps drivers in the long term is one of those controversial and unresolved mysteries of the road, but my eye-opening experience at Bondurant raises the curious idea that we buy cars—for most people one of the most costly things they will ever own—with an underdeveloped sense of how to use them. This is true for many things, arguably, but not knowing what the F9 key does in Microsoft Word is less life-threatening than not knowing how to properly operate antilock brakes.
This uneasy idea is one of the many unresolved tensions and contradictions found in driving and the traffic it spawns. There is the contradiction of the car itself: With its DNA steeped in racing, today it’s often just part of a loosely organized, greatly inefficient mass-transit system, a “living room on wheels.” To drive safely is often to become rather bored, which may lead us to become distracted and thus less safe. On the other hand, if we drove like racers, we would have little problem becoming distracted or falling asleep, but we would inherently be driving less safely. (Even the most skilled drivers cannot overcome the fundamental physics of things like stopping distance.) We all think we’re better than the average driver. We think cars are the risk when on foot; we think pedestrians act dangerously when we’re behind the wheel. We want safer cars so we can drive more dangerously. Driving, with its exhilarating speed and the boundless personal mobility it grants us, is strangely life-affirming but also, for most of us, the most deadly presence in our lives. We all want to be individuals on the road, but smooth-flowing traffic requires conformity. We want all the lights to be green, unless we are on the intersecting road, in which case we want those lights to be green. We want little traffic on our own street but a convenient ten-lane highway blazing just nearby. We all wish the other person would not drive, so that our trip would be faster. What’s best for us on the road is often not best for everyone else, and vice versa.
The reason I have avoided talking about the negative environmental consequences of the car is that I believe, as was once said, that it will be easier to remove the internal-combustion engine from the car than it will to remove the driver. With fuel economy liberated by some renewable, sustainable fuel source of the future, all the dynamics of traffic I have described will only become more amplified. As Larry Burns, vice president of R&D and strategic planning at General Motors, put it to me, “Of all the externalities of an auto that I worry about—energy, environment, equality of access, safety, and congestion—the one that I think is toughest to solve is congestion.”
Even if the driver is still in the car, whether he or she will be driving in the future is another question. Virtually all of the perceptual limitations we have in driving—blind spots, overdriving our headlights, problems in detecting the rate of closure—are being addressed by scientists and car manufacturers. High-end cars already bristle with these features. An ad for BMW’s xDrive system, which “uses sensors to monitor the road ahead,” puts it succinctly. It says, “xDrive reaction time: 100 milliseconds. Human reaction time: unnecessary.” Technologies like “gaze detection,” in which the car will tell the driver that he or she is not paying attention (by tracking eye movements), are on the horizon.
The future of driving will probably look a lot less like the track at Bondurant and much more like the 200,000-square-foot parking lot at AT&T Park (ordinarily home of the San Francisco Giants) during the World Congress on Intelligent Transport Systems. The parking lot had been converted into a “Innovative Mobility Showcase” for any number of high-tech traffic devices. It looked like a kind of strange carnival of human limitations. There were “Intelligent Intersections” that could alert drivers when an approaching driver did not seem, as calculated by sensors and algorithms, intent on stopping and “Dynamic Parking” demonstrations that promised to end, through real-time sensors, the search for open parking spots.
I was riding in a Cadillac CTS with C. Christopher Kellum and Priyantha Mudalige, two researchers with General Motors. The car, via GPS technology and receivers, was communicating with the other cars, also equipped with the technology. GM calls its technology “vehicle to vehicle,” and the idea is that by connecting all the cars in a kind of mobile network, this shared intelligence can help you “watch for the other guy,” as Mudalige put it. A screen displayed the fact that we were connected to two other vehicles. The researchers are aware that any system released into the real world would have to contend with hundreds more at a time. “We do lots of simulations to understand what happens when there’s two thousand vehicles in the same spot,” said Kellum. “We need an intelligent way to parse out what information is important and what’s not important. If there’s an accident a mile ahead, you want that information. If it’s just some guy driving a mile ahead, you don’t really care.”
If this sounds familiar, it’s because it is: This kind of incident detection and evaluation was one of the key tasks the Stanford team had targeted in getting their robotic car Junior to drive successfully in simulated urban traffic. I was, I realized, sitting in Junior’s cousin. Kellum asked me to change lanes, even though I knew, in this case, that a neighboring car had crept into my blind spot. As I put the signal on, I felt a small, Magic Fingers-style vibration in my back. This is known as a haptic warning, and it is used so that the driver will not be overwhelmed with visual or auditory information, or to underscore warnings he or she might disregard. (As you will feel when your car has drifted off the road into gravel, haptic warnings can be crudely effective.) One of the issues that haunts driver-assist technologies like “lane-departure warnings” is that these warnings can become ever more prescient, ever more sophisticated, but drivers still have to pay attention to the warning and be able to react accordingly.
Or perhaps not. Next, Kellum asked me to drive at a steady clip toward a parked car far in the distance. “Whatever feels comfortable,” he said. He then asked me not to press the brakes. “We’re going to go up there and our car’s going to brake automatically,” he said. “In real time we’re constantly assessing how far away we are, the closing speeds, and when to start braking. I’ve done this at seventy-five miles per hour.” This was essentially the same exercise as at Bondurant, but instead of being asked to lock up the ABS, I was being asked to sit back and do nothing. I was in Junior, and I was riding shotgun. The stopped car quickly loomed into view. Time seemed to slow for a moment. (In reality, as studies have suggested, it probably sped up and this was just my memory playing tricks.) A chill shot through my body; the hairs on my neck tingled. Images of blooming air bags and the buckling necks of crash-test dummies ran through my head like a fleeting nightmare. The car came to a perfect stop.
Somewhere down the road, in some distant future, humans may evolve to become perfect drivers, with highly adapted vision and reflexes for moving seamlessly at high speeds. Perhaps, like the ants, we will turn the highways into blissfully cooperative, ultraefficient streams of movement, with no merging or tailgating or finger flipping. Long before that happens, however, a sooner future seems likely: cars driving themselves, at smoothly synchronized speeds to ensure maximum traffic flow and safe following distances, equipped with merging algorithms set for highest throughput, all overseen by network routers that guide cars down the most efficient paths on these information superhighways. Maybe this will be the traffic nirvana for which we have been searching. We would do well, though, to remember the warning from the mid-twentieth-century traffic engineer Henry Barnes: “As time goes on the technical problems become more automatic, while the people problems become more surrealistic.” Even if drivers are taken away from the wheel, can we ever take the mere fact of being human out of traffic?