What is the law code and section that states that a person cannot talk on a cell phone while driving?

My friend is a lawyer and she needs to know what code and section states that someone cannot drive and talk on a cell phone.

example: "Talking on a cell phone is illegal because of law section 'automobile driving'", something along those lines. If I asked the question incorrectly please correct my "knowledge" of how to state a law "code".

In Pennsylvania, there is no state-wide ban of speaking on a cell phone while driving. It is illegal under some municipal laws in Pennsylvania.

There is a website that summarizes state laws that ban cell phone use in cars while driving. http://www.ghsa.org/html/stateinfo/laws/cellphone_laws.html

If your friend is a lawyer, she knows that this is a state by state issue or she's a really crummy lawyer.

Depends on your state: California Vehicle Code [VC] §23123

It depends on what state you live in. Most don't have such a law, but a few do.