In a new AAA Foundation for Traffic Safety study, researchers compared the levels of mental distraction associated with the use of hands-free technologies in ten 2015 vehicles and three different smart phones. They found that every system increased mental distraction and the likelihood of distracted driving to potentially unsafe levels. Those that performed best were relatively easy to use, required less time, and generally had fewer errors. Test subjects used voice commands for making calls and changing music. The researchers rated mental distraction on a five-point scale, with category one representing a mild level of distraction and category five representing the maximum level of distraction.
For reference purposes, a level 1 distraction is comparable to listening to the car radio, level 2: talking on a phone, level 3: sending texts from a voice-activated system in an error-free phone that works perfectly, and level 4: updating social media while driving.
As the chart below indicates, most of the 2015 models tested rated a “high distraction” with one car, the Mazda 6, rating as a “very high distraction.” Using Apple’s Siri was also rated as a “high distraction.”
One often hears justification for designing the features into cars and their use by drivers that “hands-free is risk-free.” This research and the earlier research by AAA clearly indicate that we can still be distracted even when looking at the road. The issue is not our vision, but rather our ability to concentrate on multiple tasks at the same time. Simply stated, we cannot multi-task. Instead, when trying to perform two cognitively demanding tasks, we switch attention from one task to the other. Our brains are not wired to do two cognitively demanding tasks simultaneously.
Another part of the study underscored just how limited we are as human beings when we try to do complex competing tasks. Even when study participants stopped using the voice-activated system, it took them 18 to 27 seconds before their full concentration was able to be returned to the driving task. For Siri it was 18 seconds, and for the built-in systems up to 27 seconds.
Just because we have the ability to use voice-to-text, prudence would require us not to do so. They still contribute to distracted driving while in use and even after we stop using them. Perhaps those of us who say we only text at a stop light should also think about whether we want to do so, given the persistent adverse effects on our concentration. Even if you do not cause a car crash if you are distracted, you can’t protect yourself from other distracted drivers.