If you read my post earlier this week on how to avoid a Red Light Ticket from a camera in Mesa, you understand where the line is that gives to a Red Light Ticket. If you made a U-Turn without crossing that line you clearly would NOT get that ticket
The actual law that defines this in Arizona is in Arizona Revised Statues, Chapter 28
28-752. Limitations on turning around
A person shall not turn a vehicle to proceed in the opposite direction on a curve or on the approach to or near the crest of a grade if the vehicle cannot be seen by the driver of any other vehicle approaching from either direction within five hundred feet.