Turns out using hands-free technologies to talk, text or send email while driving is not as safe as many people believe, according to a new study conducted by the University of Utah for the AAA Foundation for Traffic Safety.

The research found that as mental workload and distractions increase, reaction time slows, brain function is compromised, drivers scan the road less and miss visual cues, potentially resulting in drivers not seeing items right in front of them including stop signs and pedestrians.

The report notes:

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.”

Researchers measured brainwaves, eye movement and other metrics to assess what happens to drivers’ mental workload when they attempt to do multiple things at once.

The results were used to rate the levels of mental distraction drivers experience while performing each of the tasks. The levels of mental distraction are represented on a scale, as follows:

– Tasks such as listening to the radio ranked as a category “1” level of distraction or a minimal risk.

– Talking on a cell phone, both handheld and hands-free, resulted in a “2” or a moderate risk.

– Listening and responding to in-vehicle, voice-activated email features increased mental workload and distraction levels of the drivers to a “3” rating or one of extensive risk.

Professor David Strayer, lead author of the study, says:

These new, speech-based technologies in the car can overload the driver’s attention and impair their ability to drive safely. An unintended consequence of trying to make driving safer – by moving to speech-to-text in-vehicle systems – may actually overload the driver and make them less safe.”

More on this story from NPR.

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