Problem is, I'm not sure of the different nuances or, well, I guess we could call it syntax, though that's probably wrong.
I'm writing a Batman fanfiction and going with the DC Atlas that puts Gotham City in NJ. If radio codes vary by city, I'm not picky about whether Gotham is more like Newark, Trenton, Atlantic City, etc. I just want to make sure that if I'm using Trenton codes at the start of the scene, I don't suddenly switch to Newark.
So, here's the situation. In the fic, Batman has been unmasked and involuntarily committed to Arkham Asylum. He broke out, but subsequently realized that he had to go back. He contacted (retired Commissioner) Gordon who negotiated a situation where Bruce would surrender to police provided he could take care of one piece of business.
Gotham Police is sending several squad cars to the rendezvous point. One of the assigned vehicles has a 16-year-old ride along passenger. A few years back, Batman helped this kid out of a bad situation and the kid doesn't want to be dropped off--he wants to go along and thank Batman. (I realize I'm stretching a point here, since my research on ride along tells me that normally a civillian observer would not be allowed into a dangerous situation. Between Gordon's powers of persuasion and the fact that it's probably not smart to drop off a lone teenager in downtown Gotham after dark, I'm going to go with an exception being made.)
What I need to know then are:
1) The radio code designation for a civillian observer (and if there's a special one for a minor, that one.)
2) The radio code designation for picking up and/or escorting a mental patient.
3) Could a second shift patrol car identify itself as 'District 8, Bravo Three-Oh-Two'?
4) Would a dispatcher acknowledge the inquiry and advise the officer to await instructions with the term "Copy, 302, 10-6"? or "10-6, 302"? (I'm also caught between wanting things to be accurate and wanting the reader to understand what's going on without having to print a translation at the end of the chapter...)
It's not a long scene by any stretch, but I want to get it as right as possible.