Entune Rated as Least Distracting Voice System

Toyota’s voice-activated system is no more distracting than an audio book, according to the AAA Foundation for Traffic Safety, while most such systems can cause “inattention blindness” for drivers:
Toyota Voice System Is Least Distracting, AAA Study Finds - Businessweek

The detailed PDF reports of the study may be downloaded on this AAA Foundation page:
Measuring Cognitive Distraction -- Part II (2 New Reports) | AAA Foundation for Traffic Safety

The Entune vehicle tested was a Prius v Three, 2012.