Hands Free for All?

So, as many of you know, due to the dangers of cell phone usage while driving, many states have made cell phone usage while driving a punishable offense. In order to use a cell phone while driving, drivers must use some type of hands free device. My understanding is that this allows the driver to keep both hands on the wheel. It also helps the driver keep their eyes on the road and not looking away. There are signs all over the place that talk about using hands free devices while driving. Fair enough, I totally support this initiative.

This brings us to my thought of the day. If two deaf people are driving together in a car, should they be allowed to talk to each other? Oddly enough, I haven't seen a "sign" for that...