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Texting most dangerous distraction on road, study finds

Professor Ioannis Pavlidis (front) and computer science doctoral student Ashik Khatri spent time curating the data they received from their collaborators at the Texas A&M Transportation Institute. | Courtesy of Ioannis Pavlidis/The Cougar

Researchers partnering with the Texas A&M Transportation Institute have identified three kinds of distractions that plague drivers: cognitive, emotional and, perhaps the most dangerous, sensorimotor — which includes texting.

Director of Computational Physiology Ioannis Pavlidis and Robert Wunderlich, the director of the Center for Transportation Safety at Texas A&M, published a paper Aug. 15 in Scientific Data on their research, which utilized a video game-like driving simulator to test the effects of various stressors on human driving performance.

“The experiments took place at Texas A&M, but we did a major part of the design of the whole thing, and we did, exclusively, the quality control, curation and data analysis,” Pavlidis said.

The entire data set contained more variables than they could look at, Pavlidis said, so they published their findings for other scientists to review.

Improving safety

The research was funded by a class-action lawsuit against Toyota for which Wunderlich was the principal investigator. He said his role in the project was “to establish the framework for what the big questions were.”

“We needed to look for deviations that would make a difference to safety,” Wunderlich said. “If the jitter in your steering wheel goes up, that doesn’t really make any difference unless you’re driving outside your lane, right? What we were looking for was: In what circumstances did you make a move outside your lane?”

The research team used multiple variables to determine the subject’s level of distraction while driving. Pavlidis said nasal perspiration was a proxy for stress level, or sympathetic arousal, which indicates how much stress a driver is under.

Steering wheel angle measurements showed how much the steering wheel deviated from a neutral position while distracted, and lane deviation showed how much the vehicle deviated from the center of the lane, Pavlidis said. The other performance variables were acceleration, speed and braking.

“And that’s where we found in the texting — what we call sensorimotoric, where you’re having to use your eyes and your hands and your brain while you’re trying to drive — we saw deviations that are potentially important to safety,” Wunderlich said.

The team used a sophisticated driving simulator at the Transportation Institute that contained software allowing the researchers to control every aspect of the driving experience, Wunderlich said. The research was conducted in real cars on a test track.

“It’s very similar to a video game, only it’s as if you can program your video game yourself to say, ‘OK, I want you to drive along this road,’ and at some points there’s gonna be a construction work zone with cones, and sometimes you have to stop at a signal — that kind of thing,” Wunderlich said. “It allows us to program and make it the same experience for everybody.”

Computer science doctoral candidate Ashik Khatri has been a student of Pavlidis since he was an undergraduate at UH and worked with him on the research. Khatri was a part of the data collection team and ensured the software of the research was working correctly.

Khatri said the research can ultimately help people become safer drivers.

“The first step would be obviously to measure the things that can lead to a lot of stress and bad driving, which we’ve done,” he said.  “The next step is to see how we can intervene and help the drivers become less distracted and bring their focus back onto the driving itself.”

For the sensorimotoric distractions, Wunderlich said they just had the subjects text on their phones while in the driving simulator.

Wunderlich said researchers operating the simulator asked subjects questions to cause cognitive and emotional distractions. To create cognitive distractions, subjects were asked things like math questions or the capitals of different states. For emotional questions, they were asked about their personal lives.

Wunderlich said that emotional distractions were harder to induce because there are safeguards in research against getting people too emotionally stressed. 

“They don’t let you get people really emotional,” Wunderlich said.

The sympathetic, or uncontrolled, responses they tested for were heart rate, heart rate variability, hand and paranasal perspiration and facial expression, giving researchers a picture of how the stressors physically affected the drivers.

Unlike emotional and cognitive distractions, Pavlidis said, only texting was found to cause lane deviations. | Thom Dwyer/The Cougar

Instinctive corrections

“The second result was that, in all three cases … when they were under the three types of stressors, the steering was becoming a lot more intense,” Pavlidis said. “So, they had, in informal language, a lot more jittery steering.”

Wunderlich said researchers had control tests where drivers were not challenged with distractions, so they could compare them to the actual stressor test results.

“The third result,” Pavlidis said, “was that although the steering was a lot more jittery, it resulted in lane deviations only in the case of texting and driving.”

The reason lane deviation was not present during cognitive or emotional distractions was because the jittery steering was automatically counterbalanced by instinctive motions, Pavlidis said. They believe the instinctive corrections were due to a small part of the brain called the anterior cingulate cortex — the part of the brain that handles conflict — which, Pavlidis said, cannot work properly when texting and driving because the person’s eyes are not focused on the road.

This deprives the anterior cingulate cortex of necessary resources such as vision needed to instinctively correct driving deviations. If a person is texting while driving, they are using their eyes as well as their hands for two tasks at once, Pavlidis said.

“We’re really excited about putting this data set out so that other people can use it to see if they can discover things that we couldn’t,” Wunderlich said. “Even though we had a long project that was funded pretty well, you never ask or answer all the questions that you might, and we put a lot of effort into this. It was a great collaboration.”

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