I just saw something on the news about using hands-free device while driving a car is no safer that is more of a risk . So it could be the same with riding a bike .
That may be true, but I never ever use my phone while in motion. It's not only unsafe, it's generally a bad idea to do so, anyways. The main reason I use it is to make sure I don't accidentally misplace my phone. And I use it to track my bicycle speeds, too.