Surprisingly, research suggests that it is not. While hands-free devices do help drivers keep their eyes on the road, talking on the phone can still cause a mental distraction.
A University of Utah study found that drivers using a cell phone missed twice as many traffic lights as drivers without a phone; a concerning thought considering that a serious car accident could result from any one of those missed lights.
That was true regardless of whether they were using a hands-free device. The study concluded that phone conversations distract drivers in ways that passive listening does not.