With headset and especially bluetooth cellphones readily available, there is very little reason to be caught holding your cell phone while driving.
My wife, in preparation for this law bought a bluetooth headset and called me from it. Sounded like she was hollering in a tunnel.
She got another one and it won't pair with her phone.
I, on the other hand, cleverly went to Wally World, and got a little gadget that holds the cellphone on the end of a stick and fits in my cupholder. Put it on "speakerphone" and it works like a dream. Lo-tech wins every time.