Texting has long been condemned as the worst kind of distracting behavior a person can engage in while driving. Now a new study by the Texas A&M Transportation Institute suggests that while a "sixth sense" can help protect drivers during more moderate distractions, it does not work if a person is sending a text message while behind the wheel.

TTI recently completed a study which monitored and measured the stress levels of 59 volunteers in a driver simulator. The institute is leading a three-year research transportation safety research project that partners with the Texas A&M Dwight Look Laboratory, the University of Houston's Computational Physiology Laboratory, and the University of Michigan Transportation Research Institute. Funding for the project comes from the Toyota Economic Loss Settlement.

During the driving tests, volunteers wore a heart rate monitor and a skin conductance device. They were also recorded by a thermal imaging camera.

Volunteers drove the same course four different times. These tests occurred under normal conditions, while the driver was being asked cognitively challenging questions, while they were asked emotionally charged questions, and while they were texting.

In each of the three scenarios in which the driver was distracted, they became more stressed. However, researchers found that drivers who were distracted by cognitively challenging or emotionally charged questions were still able to stay within their lane and on the virtual course.

"The driver's mind can wonder and his or her feelings may boil, but a sixth sense keeps a person safe – at least in terms of veering off course," said Ioannis Pavlidis, director of the Computational Physiology Laboratory. "What makes texting so dangerous is that it wreaks havoc on this sixth sense."

Pavlidis says the anterior cingulate cortex of the brain, or ACC, is able to intervene during stressful situations to counterbalance jitters and absentmindedness. However, hand-eye coordination is essential for this function to work properly. The loss of this hand-eye coordination among texting drivers in the test made it more likely that they would leave their lane or run off the virtual course.

Texting has been described as a particularly dangerous form of distracting behavior because it impairs a person's vision, cognition, and manual dexterity. When manipulating a phone to send a message or use a smartphone, a person takes their eyes off the road, turns their attention to the phone, and has at least one hand off the wheel.

Although the ACC function can help a driver stay within their lane, researchers cautioned that it is not enough to prevent an accident in certain circumstances.

"It's well known that high levels of stress can contribute to driver error by slowing reaction time, so alerting a stressed driver of that condition has the potential of improving safety," said Mike Manser, manager of TTI's Human Factors Program.

Researchers will continue to look into the effect of stress on driving ability by performing stress tests on volunteers who drive a vehicle on a course at Texas A&M's RELLIS Campus. They are also working to develop sensors that will detect both driver stress levels and vehicle errors such as unintended acceleration. By the third year of the research project, the team hopes to develop technology that can warn of abnormal conditions with either the driver or the vehicle itself.

"We are pleased to work with TTI researchers on a meaningful and potentially high impact project," said Reza Langari, head of the Engineering Technology and Industrial Distribution Department at Texas A&M. "The work brings together expertise in vehicle dynamics, human factors, machine learning, and decision analysis to address an important problem in transportation safety – the detection of abnormal driving conditions."