After reading this thread, I restrained myself from waving at other Prius drivers in this semi-small Southern town. Then, today, a blue Prius stopped next to me at a light. I turned my head to see if it were one of my Prius-driving friends, and they were waving! Strangers! I smiled and waved back - it's the small town Southern thing, but just over the car!
I made friendly eye contact with another 2010 BWP while she was turning in to where I was leaving and it was briefly awkward for a sec; I think she thought I was checking her out, but realized I was staring at her because of her 2010 BWP. .You had to be there.
<18,000 Insight-I's were made and sold worldwide, so there aren't many out there. When I'm in mine I usually wave, flash lights on the rare occasion when I see another one. Most totally ignore me, like they're oblivious and didn't even notice that I'm in an Insight-I. In fairness, though, it isn't very distinctive-looking from the front. I notice other Prii but don't wave, far too many of them around here. I suspect that most of the motoring public don't know or care what the car they are driving looks like, so they don't recognize a car like theirs when they see it. They're much too busy fussing with their cell phones, Garmins, etc.
Last week I noticed that the cars stopped directly ahead & behind were Prii! Three in a row! Woot! I should have honked three times.
When I had a 1st gen Miata (the kind with the pop-up headlights), fellow Miata owners would flip the lights up and down sort of like a wink, at each other. With my 2nd gen Miata, there's an occassional wave. On the Harley, my arm gets tired waving at all the other passing bikers. It's actually sort of silly. I finally got to the point where I would do the "biker wave" to the first 10 or so bikers that I passed, after that, no more waving...otherwise, you wind up riding around with one hand all day. With the Prius, there are SO many of them (and so many clueless Prius drivers), I don't even bother. The waving thing comes from car enthusiasts and bike enthusiasts. I would venture to guess that most Prius owners are not "car people"...they just want to get from "point a" to "point b" as efficiently as possible.
We Miata (MX-5) owners will usually wave when our tops are down, but flash the headlights if the tops are up.
Paradox: I think your observation unmasks the "universal Prius salute." Raise your right hand with a loosly closed palm with fingers wraping backward toward your face. Now, quickly rub your thumb and index finger together in the international sign for money. I have traveled the world and have yet to encounter a cultural setting or language where this gesture was unknown. This established gesture of thrift, instantly conveys why I drive a Prius.
I had a Jeep Wrangler as a rental for 2 days once. You would not believe how many other Wrangler drivers waved at me! I have not even had 1 fellow Prius driver even look at me! Oh well I can just wave at myself on the mirror!