Distracted driving killed 3,331 people on American streets in 2011, yet car manufacturers continue to outdo each other to add more infotainment distractions in their vehicles. These systems are expected to increase five-fold by 2018, according to AAA. Carmakers seek to show their commitment to safety by making their distractions – onboard dinner reservation apps and social media, for example – hands-free. But a growing body of research indicates that there is no safe way to combine driving with tasks like dictating email or text messages.
AAA recently teamed up with experts at the University of Utah to conduct the most in-depth analysis to date of the impact of cognitive distractions on drivers’ performance. They found that some hands-free technologies, like voice-to-text email, can be far more dangerous than even handheld phone conversations. Unlike previous studies, they also found that conversations with passengers can be more distracting than those on the phone, but only if the passenger is kept unaware of what’s happening on the road.
The researchers had subjects first perform a series of eight tasks, ranging from nothing at all to usage of various electronic devices to something called OSPAN, or operation span, which sets the maximum demand the average adult brain can handle. For the OSPAN, the researchers gave subjects words and math problems to recall later, in the same order, as a way to “anchor the high end of the cognitive distraction scale developed by the research team,” according to AAA’s Jake Nelson.
The subjects then performed these eight tasks while operating a driving simulator, and then while driving on residential streets in an “instrumented” vehicle that captures information about the driver’s eye movements and brain activity.
In each environment, researchers studied how the additional tasks added to subjects’ “cognitive workload” and diminished their eye movements. They found that as drivers devote more mental energy to other tasks in addition to driving, the less observant they become, and the more they fail to scan for roadway hazards.
This bolsters the conclusions of previous experiments: that when drivers are mentally distracted by some other task, they get tunnel vision. They keep their eyes fixed on the road in front of them to the exclusion of everything else — the rear-view mirror, side mirrors, and “safety critical roadside objects” and “cross traffic threats” — such as pedestrians.
The AAA study also found that greater “cognitive workloads” slow drivers’ reactions to events like a ball rolling in front of the car and a kid running out to catch it. (Reaction times were measured with the simulator, not the instrumented vehicle driving on real streets.)
The researchers conclude that hands-free communications can be significantly more distracting and dangerous for drivers to engage in than passive tasks like listening to music: