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Anatomy of a Car Crash

Let science show you how to skip your next roadway disaster.


Read when you’ve got time to spare.

Firefighters help clean up the scene of a fatal accident that killed seven people when the SUV they were riding in crashed off an I-25 overpass and burst into flames early Thanksgiving morning on Nov. 28, 2008, near Johnstown, Colorado. Photo by Brian Brainerd/The Denver Post via Getty Images.

Car crashes are mysteries. Even though roughly 6 million of them happen each year in the United States alone, we seldom learn much. When we do drive by a crash, we often slow down to have a look. But there’s never much to see. Two crumpled cars. Maybe one upside down. An ambulance closing its doors. I usually feel bad—for those who may have gotten hurt (or worse), of course, but also because my rubbernecking contributes to the logjam of cars behind me.

I want to know what happened because there’s an obvious payoff. I want to make sure that the same thing doesn’t happen to me. Was it some bonehead move that I would never make? Or did someone commit a minor transgression and then pay a major price? Give me an instant replay like I get when I’m watching football. A slow-motion video with expert commentators who draw diagrams and who reveal in explicit detail how it all went down.

Without the details of how crashes happen, we tend to dismiss them as the work of “idiots”—drivers who occupy the lower echelons of driving skill and common sense. But while humankind’s measured intelligence is increasing, so is the number of deadly car crashes. After a lifetime of improvement, we saw an 8 percent jump in crash fatalities during 2015, the largest in 50 years. That number rose again in 2016, when more than 40,000 people died in collisions.

Fortunately, science is coming to the rescue. We no longer have to rely solely on dents, skid marks, and the lawyer-vetted remarks of drivers to figure out what happened and to tell us how to avoid the next crash. In a landmark study published in 2008, researchers at the University of Michigan combed the scene of 6,950 crashes to give us a more detailed analysis of what happened during each crash. Naturalistic driving studies are now equipping cars with accelerometers, sonar, sensors that track driver inputs, and lots of video cameras. Drivers sign up to participate in these studies, and they sometimes crash, leaving researchers with valuable data. We’re also benefiting from the rise of road cams—dashboard-mounted video cameras owned by everyday drivers, aka cammers, who cruise around, record crashes, and then post them on websites like Reddit.

I’ve rolled up the fruits of these efforts to provide a closer look at what the evidence tells us are six of the most common crash scenarios. None of these types of crashes are rare occurrences or the work of the especially incompetent. They happen as a result of simple misunderstandings of what can happen when cars, roads, and minds of even the most intelligent and responsible drivers all come together.

The Rolling Right Turn on Red

You approach a red light, and you’re about to turn right. You slow down but don’t come to a full stop. As you continue to roll, you look to your left to see if there are any cars coming at you from that direction. You turn your head back to the right and suddenly, out of nowhere, there’s a pedestrian or a bicyclist.

The rolling right turn on red overwhelms our attentional capabilities. While we’re fearing for our life in one direction, we’re driving in another. What could possibly go wrong? Why do we attempt this impossible feat? Aside from our unshakable confidence in our multitasking superpowers, many drivers don’t even know that the law requires us to come to a full stop before turning.

The rolling right on red now accounts for 6 percent of all pedestrian fatalities, and the number is on the rise. Worse still, 21 percent of the deaths happen to kids. Even when a car is moving slowly, children have a four times greater chance of dying than grown-ups.

Solution: Slow your roll when making this very simple transition. It’ll cost you about three seconds, and you just might save a life.

Falling Asleep

Since we have yet to invent the handheld snooze-a-lyzer device for the police to carry, we’ve historically had to guess how often drivers fall asleep at the wheel. But driving studies and cammers are revealing that our previous guesses were far too low. We now estimate that about 7 percent of all car crashes, and 21 percent of fatal crashes, happen to drowsy drivers. Recent surveys find that 37 percent of all drivers have fallen asleep while driving at least once in their lives, 11 percent during the past year, and 4 percent during the past month. And our increasingly busy schedules are making the problem worse.

How does it happen to us? “People are horrible judges of their own sleepiness,” Mark Rosekind, who was administrator of the National Highway Traffic Safety Administration under President Obama, reminded me. According to Rosekind, who is now the safety chief at Zoox, an autonomous-car startup, drivers are even less aware of the danger of microsleep—brief intervals during which our brains just shut down and go offline for few seconds. Rosekind said that we don’t know when we’re microsleeping, are about to, or even when we just did. “Our brains can put us to sleep anytime.”

It won’t happen to us, right? Here’s a cammer who caught himself falling asleep and crashing in front of a sign that reads “Cemetery, 1KM.” One YouTube commenter said: “He almost made it.”

Solution: Did you sleep less than seven hours last night? Is it late? Are you alone in the car? No caffeine on hand? These are the elements of disaster. Delete some of them from your situation or get out of the car.

Loss of Control

It’s hard to imagine losing control of your vehicle, but it accounts for 11 percent of all crashes. It’s comforting to think that these unfortunate drivers occupy the bottom 11 percent of the driving skill scale, but science has some humbling news for us. It turns out that most of us think about driving skill far too simply. A classic study shows 50 percent of all drivers rank themselves in the top 20 percent of driver safety and skill. Where are the errors in our thinking? Racer and test driver Andy Pilgrim told me that we have surprisingly little technical mastery of our own vehicles. Most drivers are “not even close to the capability of their car, as far as going fast,” said Pilgrim, who can show you things in your minivan that would blow your mind.

Aggressive maneuvering and taking a sharp curve too fast account for about 5 percent of all crashes. Another 2 percent happen when we don’t slow down for water on the road.

The remainder of these crashes happen when another driver or even a sudden turn in the road puts us in a surprise situation that demands an instant response. We imagine ourselves coolly responding when something unexpected pops up, but most people overreact and overcompensate and sometimes kick their car afterward.

Solution: You don’t have to crash your car all by yourself. Your car, the weather, and other drivers are willing to help make it happen. Be sure to factor them into your thinking.

Into the Blind

Ever make a left turn at an intersection when there’s a huge bus blocking your view of what’s coming from the other direction? Or cruise through a red light thinking that there won’t be another car coming across your path? Or even race down a road not realizing that it just might end at some point? The data tell us that 12 percent of all crashes happen when drivers do these things.

We seem to have this natural belief that if we can’t see something, then it must not exist. When we’re kids and the bedroom light is out, we are convinced that there is a monster under the bed. When we grow up, we become certain that there is no monster under the bed. The reality is that there may or may not be a monster under the bed. The crash data remind us that this misunderstanding is widespread among grown-ups.

Solution: Always check for monsters.

The Rear-Ender

Your first job when driving: Don’t hit the car in front of you. As simple as it sounds, hitting the car in front of us accounts for between 23 percent and 30 percent of all crashes.

We drive close to the car in front of us because we think it’ll get us there faster. It’s true, technically, but just barely: Science says we save 26 seconds per day as a result of our hurrying. We also imagine that the driver in front of us will wait until we’re done with our text before he locks up his brakes. The crash data clearly demonstrate that she won’t. We think that rear-end crashes are harmless fender benders. But sometimes cars twist and flip and crunch stuff that gets caught in between them (pictures).

Solution: Leave some space. You’re not getting there any sooner.

Distracted Lane or Road Departure

Your second job when driving is to stay in your lane. Thirty-three percent of all crashes happen when we don’t stay in our lane, or even on the road.

Our firm belief in our multitasking superpowers strikes again. In addition to the distraction of phones, our attention gets pulled by roadside crashes, billboards, activities inside the car, and mind wandering. Humans are not natural performers when it comes to keeping an eye on much of anything and even less so when asked to attend to several things at once. Somewhere, a gnat just cracked up his friends by quipping: “I have the attention span of a human being!”

Solution: Stow the technology and do your best to pay attention. It’s way harder than it looks.

* * *

Science isn’t going to soon provide us with flying robot guardian angels that swoop down and save us at the last second. Self-driving cars may help, but they’re still a ways away. So work these six lessons into your driving game then roll down your window, give the Grim Reaper the middle finger, and live to be 90.

Steve Casner is a research psychologist, a jet pilot, and the author of Careful: A User's Guide To Our Injury-Prone Minds.

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This post originally appeared on Slate and was published November 21, 2017. This article is republished here with permission.

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