I started waving at fellow drivers of similar vehicles in the 1960s when I drove a TR-4. Kept it up when Id drove a Corvette and even in my Saab days there was a sense of camaraderie that lead to waving. I wave now from my Jeep and when I see another RV be it motorhome or towable, I wave on two lane roads where I can see the oncoming driver and maybe s/he can see me. I have seen everything from two fingers lifted from the top of the wheel to an all out full arm raised wave. Mostly I see no response. It may be in part because I cannot see past the reflection on the windshield or the movement is too small for me to see. Or it may be that they couldn't see me.