Originally Posted by wa8yxm
Waving is good but on the interstate you are likely too far and too fast to do it.
As for flashing headlights.. This is a standard "Speed trap ahead" warning to other drivers and at least one state (FL) passed a law outlawing the practice that just went into effect.
Source, news article "Strange new laws for 2013" Yahoo news search should find it, or Google.
Oh, and it's also illegal for a driverless car to be going down the freeway without a human passanger in CA.
I think the Florida law changed from prohibiting "flashing" to allowing it,
(a Freedom of Speech issue)!
BTW, when I am driving, I notice a lot of waves directed toward me!........(People sure are friendly)!
However, I seem to get a lot more "single finger" waves, (and fewer full hand waves), than I used to.