Yes, and some (especially highway patrols) do. However, most police officers will go out of their way to avoid citing another officer. This practice is called "professional courtesy," and it is somewhat controversial.
The Motor Vehicle Laws.
For a speeding ticket issued by a Police Officer, Yes! For an alleged speed camera violation, No!
consequence
No, generally, regular citizens cannot charge a police officer with speeding. However, citizens can report their observations to the respective police department, and it is up to the department to investigate and take appropriate action. It is ultimately the responsibility of the police department to enforce traffic laws for their officers.
The police officer does not set the fine. The fine is based on state law. That is determined by your speed and where you were speeding. In a school zone, and construction zone, the fine is more.
It doesn't matter where they sit. If you are speeding, they can write you a ticket. How and where they are when they determine you are speeding doesn't matter. (Neither does the state!)
It all depends how fast you were going, and who all happened to be in the vehicle. If there were multiple people in the car, it could be "Wreckless Endangerment, Speeding and Ect. Yes, it is legal for the officer to give you eight tickets.
answering calls, driving around in a squad car, getting out of speeding tickets
In some states, an off duty police officer can write a speeding ticket. It will depend on the laws in your specific state. You can always go to court to fight the ticket.
Police Officers
No. Auxiliary police officers are not officers of the court.
Georgia does not have a statue of limitations on speeding tickets. When a police officer pulls you over again, that ticket will appear on his computer as paid or unpaid.