Here in the Socialist Republik of New Jersey: You can't have a weapon in the cab at all, unless you are one of those rare individuals who actually have been granted a CCW.
It's not written, but the etiquette is to hand over your weapon permit along with your licence, registration, and insurance card. Respectfully follow the Officer's instructions from there.
Hah, I live in Tennessee, home of the "sumbitch needed killing" defense. Pretty easy to get a CCW permit here, although I've never bothered. I try to avoid places and situations where I might need to go armed, and besides, I have one of those faces that makes people leery for some reason. I've never had any problems with being hassled, even though I'm just a little guy. I've even had people I hadn't even really noticed roll down the window and ask me what they did to make me give them "such a mean look". So I've never carried a weapon and never felt the need. Even at home I keep no loaded guns, although I do keep a twelve-round pistol mag loaded with about six rounds of Silvertips just in case I need to quickly slam it in, and I do have a box of #4 high brass close to my 1100. Obviously I'm not a big home defense guy, but on occasion, such as when I'm going to be out of town, I'll load four rounds (two #4 & two #00) into the 1100 and fully load a couple mags for my wife, just in case. (She might not hit anything, but the whole neighborhood would be awake and calling the cops, and the sound of an auto racking a shell is almost as good as that of a pump.)
I am however near-fanatical on the RIGHT to go armed, should I choose to exercise it.