As a Reddit user eloquently pointed out, every driver knows the feeling of driving 20-30 km and not remembering how you went through it, or even how you survived it. It’s almost like a sixth sense that protects you – but it doesn’t help you at all when you’re texting.

One of the 59 volunteers in a distracted driving study by the University of Houston and Texas A&M Transportation Institute sits in a high-fidelity driving simulator.
Credit: Malcolm Dcosta

Led by Ioannis Pavlidis from UH and Robert Wunderlich of TTI, the research studied how drivers behave when they are absent minded, emotionally charged or engaged in texting. The study involved 59 volunteers who were asked to drive the same segment of highway four times — under ‘normal conditions,’ while being distracted with challenging questions, while distracted with emotionally charged questions and while preoccupied with texting trivialities. To avoid any bias, the order of the drives was randomized.

Of course, in all three distracting cases, the drivers’ ability decreased significantly, but texting caused jittery handling and significant lane deviations, creating overall completely unsafe driving conditions.

“A likely explanation for this paradox is the function performed by a part of the brain called the anterior cingulate cortex, or ACC,” Pavlidis said. “ACC is known to automatically intervene as an error corrector when there is conflict. In this case, the conflict comes from the cognitive, emotional and sensorimotor, or texting, stressors. This raises the levels of physiological stress, funneling ‘fight or flight’ energy to the driver’s arms, resulting in jittery handling of the steering wheel.”

The ACC is, in a way, the “sixth sense” taking care of you when you’re tired or in distressed, counterbalancing jitter and nullifying or minimizing any emerging errors. But in order for the ACC to intervene it needs support from the driver’s eye-hand coordination loop. If this loop breaks, which it does when the driver texts, then ACC fails and the jitter control fails too.

“The driver’s mind can wander and his or her feelings may boil, but a sixth sense keeps a person safe at least in terms of veering off course,” Pavlidis said. “What makes texting so dangerous is that it wreaks havoc into this sixth sense. Self-driving cars may bypass this and other problems, but the moral of the story is that humans have their own auto systems that work wonders, until they break.”

The study can benefit both drivers, as well as the manufacturing community. Basically, everything that’s distressing can impede your ability to drive, and scientists want to quantify it.

“Following up on the results of our science study, we are currently looking into the development of a car system to monitor outward driving behaviors, such as steering jitter or lane deviation, as well as the internal state of the driver that causes them,” Pavlidis said. “This system, which I call ‘stressalyzer,’ a play on the word breathalyzer, may serve not only as a ‘black box’ in car accidents, but also as a driver alert and prevention mechanism, since it will continuously sense a driver drifting to distracted mode.”

But the worst thing is, by far, texting. Not only does this drastically reduce your attention, not only does it force both your eyes and hands away from driving, but it also prevents your brain from doing damage control. Just don’t do it, ever.