gesticulating on the go

When a driver makes the effort to yield for me, either when I'm on foot or driving my (P.O.S.) car, I give him/ her a little wave. I was thinking the other day how inadequate the wave is in this capacity. I mean, translated into verbal language, it's "Hello" , right? (or "ello-Hay" if you're some Pig Latin spouting wackadoo) I would like there to be some sort of simple hand gesture that directly correlates to the phrase "Thank you". The other day I considered flashing another driver an ASL " I love you". I refrained. Wonder what sorta reception I'd have gotten?