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Eighty-six percent of American workers drive to work. But for our brains, it's more like going to war. Your first words of the morning are "fuck you" on the freeway at 8:41 am. You take your car for granted, like it's Aladdin's magic carpet. Beneath the hood and your feet on the floor mat are a million things that could—yet miraculously, mostly don't—go wrong. But your complicated brain, like that board game Risk, makes a car look like Tic-Tac-Toe. Your car is screws, gas and steel. Your brain is neurons, synapses, and 100 trillion instantaneous connections that press your foot on the pedal.
Today, though, it's tired. And it's putting you at risk. Fatigued drivers are less alert and tend to overestimate the distance between themselves and other objects, like signs, stoplights, and cars. Unsurprisingly, sleep-related accidents peak in the early morning. Even just one hour less of sleep than normal increases your likelihood of crashing the next day.This daily drive is one of the most stressful things you do. Several studies show that commuting is among our most negative daily experiences. And driving in traffic is the most stressful kind of driving. One study in urban college commuters found that students became angry at another driver more than once a day. These emotions linger. Some research suggests that long, traffic-laden commutes may cause residual stress at work. Paul Atchley, a psychologist at the University of Kansas, says, "Driving can be very emotional. You can carry it for quite awhile."Stuck in the wrong lane, you sit with nothing to do but wait out the line of cars parading ahead of you on the highway. Your blinker clicks monotonically and your mind drifts. You're in the wrong profession, watching the world get promoted before you, waiting like a crying kid in the backseat of your life. Research suggests that driving is more stressful when life is more stressful. For example, an accumulation of self-reported daily hassles is associated with higher driver stress in traffic.
In turn, stress sabotages our driving performance. Financial difficulties are linked with higher crash risk. Workplace difficulties like role ambiguity, work overload and interpersonal conflict damage our driving ability. Even having an emotional conversation increases our likelihood of driving dangerously. But perhaps the most telling example of how life leaks into driving is the repeated finding that people have higher-than-average accident and traffic violation rates six months before and after filing for divorce, and are four times more likely to be at fault in collisions than other drivers.So moments like these, when you're bored and ruminating, are often the most harrowing. "When you're inattentive and in your head, that's when you stop scanning your environment," Atchley explains. We're particularly prone to mind wandering and inattentiveness on routine driving routes, like morning commutes. One driving danger is cognitive overload—turning left at a stoplight in traffic while trying to figure out Google Maps, for instance. But another, insidious danger is under-load. When we become accustomed to a certain kind of driving, like cruising along the same freeway to work every day, we stop actively looking for hazards. We become cognitively complacent. This may explain why so many accidents happen close to home.Someone cuts in front of you and you feel—before 9 am—that you've had enough. Demanding driving, fatigue, and stress have waned your brain's willpower. In one study, researchers made some people memorize a two-digit number and others memorize a seven-digit number. Then they asked participants whether they wanted chocolate cake or fruit for a snack. The people who memorized the seven-digit number were 50 percent more likely to pick the chocolate cake over the fruit. Driving, like memorizing, is a cognitively-demanding activity. If you also haven't slept well, or are angry or stressed out on the road, you won't have the willpower you need to drive defensively and stay alert. "If your willpower center is tapped out, you're less likely to make good decisions," Atchley says.So this is when you make a decision that may one day land you in an ambulance. You start texting. Driving requires steering, stopping, scanning, monitoring other cars, navigating traffic, processing traffic rules, planning routes, and many other visual, cognitive and motor tasks. But we do most of these tasks automatically. Our brain cranks behind the scenes, while we unknowingly push it to its limits with unnecessary distractions.Adding multitasking and distractions like cell phones to this scenario is trouble. Our brains are only capable of processing four things at a time, Atchley says. "When we're distracted, we're using up [finite cognitive] resources that we need to make good decisions and see the world." One consequence is inattentional blindness, where we look at something but fail to appropriately process it. We see a family crossing the road but don't register that we need to throw on the breaks not to hit them. Multitasking and distraction use up parts of our brain that we can't afford to lose when we're driving.But today you make it fine. While you're stopped at the light, you text your boss, "Almost there," and flip on Do Not Disturb. Then you toss your phone into the cupholder. You will arrive.Read This Next: Sex Will Make You Happy at Work