There are unique aspects to every demographic and location, but those of the Deep South, where I call home, are by far my favorite collection. The South has its own pace, its own style, its own traditions and its own ways of doing day-to-day life... and trust us, we wouldn't do it any other way.
One thing we Southerners always do while driving: wave. Doesn't matter if you know them or not, whether you are coming or going, rushing or taking a "Sunday afternoon drive." Even so, it is important to note the distinction of each type of wave, as no two are created equal.
The Solo Finger: This is the common greeting thrown over the top of steering wheels while driving. It has no personal connotation, but is used when meeting any and all vehicles in the opposing lane, which by the way, is 95% two-lane.
The One-&-A-Half - A step above the Solo Finger, this involves the full finger raise of the pointer and at least a moderate raise of a secondary finger, normally the ring finger. Also without personal connotation, this is often used when the hand is out the window instead of on the wheel, but can be used as an wheel greeting as well.
The Whole Hand - Now you are getting somewhere, this means I know you! It can be thrown over the top of the steering wheel or accomanied by an arm raise from the elbow up out the window.
The Over Wave - This, oh this one, this one is for those of us who are not good at spotting people we know in oncoming traffic. This wave is usually reserved for immediate family or close friends whom you encounter in passing often. It says "HEY! You there! That I know and that never recognizes me in my vehicle! I'm HERE!"
The Quick Throw: This one, this one means "whoops, you almost got by me" When caught last minute in a wave situation and then recognizing the person in the other vehicle at or near the time of passing, the Quick Throw involves the entire arm being thrown up or out, because we all know, you either go big, or go home