This is where I found my info.
The current state laws are kind of contradictory. This is just my interpretation of them, one says its fine to certain cc displacement and the other law says they must be treated as motor vehicles.
I live in Mesa (shoot first ask latter) and I have had no problems with the local authorties. I've ridden past numerous officers, pulled up next to them at stop lights etc. My son rides his motor bike to High School everyday and he has never been questioned. I plan to keep my bike quiet and ride safetly, obeying all the traffic laws, its a great way for my son to learn the rules of the road before he gets behind the wheel of a car. Go to the web site and dig a little, see what your interpretaion is.