Arizona Driving Laws: Is it Illegal to stop in the middle of the road on a green light with cars behind you?

My bus driver, today and yesterday, stopped before the lights in an intersection and did not go. Even on a green light. About, 5 or 6 yards away was an area where she could have LEGALLY pulled over and stopped (Bike riding area). Even her supervisor said she couldnt stop in the middle of the road.

Today, she stopped in the same area, unbuckled her seatbelt and GOT UP FROM THE SEAT (Insurance issue?), walked over to a student to get something that wasnt endangering anybody else on the bus.

Is this illegal? If so, can you show the ARS law for it? Thank you.

Thanks for your answers.

Her "surroundings" were normal and clear. It was a right turn only for both sides (front and back, I dont know what to call them). She had no cars in front of her too.

28-644. Obedience to and required traffic control devices

A. Unless otherwise directed by a traffic or police officer and subject to the exemptions granted the driver of an authorized emergency vehicle in this chapter, the driver of a vehicle shall:

1. Obey the instructions of an official traffic control device applicable to the driver that is placed in accordance with this chapter.
....

I suppose someone could get a ticket if they disobeyed the instruction of a green light--which is to proceed if one can do so safely. Unlikely, since reckless driving is a much more common charge that covers nearly anything.

If she was to stop in the middle of the road on a green light while blocking traffic, thats illegal. If she was going to make a left turn onto another road, she does it in the turning lane, in which you turn when the light turns green. Depending on the oncomeing traffic not allowing her to make her turn, she must have sat there till it was save to make the turn.
But I do not know what your exact soroundings were at the time, so I can't tell you much. I just finished Drivers Ed, so thats the best answer I can give you.