You have touched on a touchy situation!!!
In NYC, if you are pulled over and for any reason, the officer decides to check the car out-frequently refered to as a pull and peek-where they pull you over and take a peek inside your vehicle, if you have ANY type of blade not in plain sight of the officer, they can get you on concealed weapons charges. Some of you law-savy blade carriers may think not, and technically you maybe right, but talk to a cop from the city, and any traffic cop will admit otherwise!
It is because of this, that I carry a Ready Edge hanging from my ski rack key chain, slid over my signal lever, I keep an old beat up/used gerber tool in glove box, and a CS Bushman in my toolbox in my trunk. Of course, on my person, there are easily three other knives, at least one of which could get me locked up at any moment!
When leaving my house once with my Chris Reeve, my father asked if I would miss it if I lost it somehow. Damn right I would! That day, on the way to the rifle range I was pulled over by a state trooper. All rifles were in back seat, locked in cases, seperate from ammo, with bolts removed. When I brought this to the officer's attention, he seemed more concerned about the CRK stick out of my right hip, then about the three hunting rifles in my car!
Goes to show you, a knife on the hip is better than a slug gun in its case!