You would not believe some to the scenes I have witnessed with people talking on a cellphone and attempting to driver their automobile. First, you and I know that some people cannot chew gum and walk at the same time, so these drivers are extremely dangerous on the road.
In my state, only texting is a law violation, while driving. How can an officer tell the difference, unless he is sitting in the seat next to the driver? In my state, a person can only be charged with careless driving, if another traffic violation is present. Example: speeding and talking on a cellphone is a contributing factor. Our lawmakers made this law as weak as possible, because they do this themselves.
I once saw a woman driving an suv. She was applying makeup, talking on a cellphone and steering with her knees. I got out of her way and expected her to crash at any time.
To answer your question, yes, cellphones are a contributing factor to road rage. Some drivers have their mind on the phone conversation and not their driving. This is a dangerous situation for all other drivers. Also, I answered a wreck where this woman dropped her cellphone on the floor of her auto. As she was attempting to pick it up, she grabbed the steering wheel, turning it, and ran off the road into a briar patch. No injuries, just a lot of embarrassment and thorns to remove.