Yes, I have driven extensively in the central US with a CB and I hear some traffic on AM but nothing on FM. Others in CB forums have had the same experience. Most (all?) CBs sold in the US today have both AM and FM capability, but it seems that it rarely gets used. I don't count myself as a "user" of FM CB because I just listen. I haven't randomly gotten on CB and announced my presence for several decades. Would someone answer if I did so on FM? I don't know. I use CB almost exclusively to monitor road conditions, and all of that is on AM. My TYT TH-9800 will scan both AM and FM frequencies and I have yet to hear anyone on FM. I have a CB on a separate antenna in case I want to transmit, but I hardly ever do. Mostly I just hear a sh*tshow with occasional business use and highway conditions.