• by Erik Sass  @eriksass1, June 12, 2013

While speech-to-text systems in cars might seem safe and convenient, in reality they’re not. “Hands free” activities can be just as distracting -- and dangerous -- as “hands on” activities while behind the wheel.

A new study performed for the Automobile Association of America by researchers at the University of Utah, study, titled “Measuring Cognitive Distraction in the Automobile,” used measures like reaction time and electroencephalographic activity to determine how distracted drivers were performing various tasks while behind the wheel of a driving simulator and a real automobile, including listening to the radio, talking to a passenger or on a hands-free cell phone, listening to a book on tape, talking on a hands-free cell phone, talking on a handheld cell phone and using a voice-to-text dictation system.

The tasks were then ranked relative to a baseline scenario (driving with no other tasks) and a maximum-distraction scenario, which involved doing a dictated math problem and memorization task at the same time.

Measured against the maximum-distraction and baseline scenarios, which were granted values of “5” and “1” at the top and bottom of the distraction scale, respectively, voice-to-text dictation was the next-most-distracting activity, scoring 3.06 out of five, which made it more distracting than using a handheld cell phone (2.45) or talking to a passenger (2.33).

Somewhat more encouraging, using a hands-free cell phone was found to be less distracting than talking to a passenger (2.27), as were listening to a book on tape (1.75) and listening to the radio (1.21). Likewise, drivers who were using voice-to-text dictation were least likely to glance at hazard locations, while drivers listening to the radio were most likely to glance.

It’s worth noting that per the study authors, “we used a perfect fidelity speech-recognition system and there was no requirement to review, edit, or correct garbled speech-to-text translations.” In other words, voice-to-text dictation is distracting no matter how good the technology behind it is. The study concludes: “The assumption that if the eyes were on the road and the hands were on the steering wheel then voice-based interactions would be safe appears to be unwarranted. Simply put, hands-free does not mean risk-free.”

Previously, a study published in April by the Texas Transportation Institute at Texas A&M University found that voice texting is just as distracting to drivers as manual texting. The Texas A&M study looked at driver response times while using manual texting, as well as voice-to-text software developed for the iPhone and Android smartphones. It found that drivers navigating a closed course with stoplights displayed a comparable level of distraction -- and therefore delayed response time -- regardless of which system they were using.