Phil's Rambling Rants
I think that the advent of cell phones was the demise of this. It is one thing to jot down the number and call later - that usually means the offence was enough that you remember it later. With cell phones people want something to happen RIGHT NOW - to the point of "Tell your truck to let me pass him"
I think both the rise and fall of this have been since cell phones started to be somewhat common. Without cell phones, it's meaningless to have the number there at all; by the time you get honked off enough to write down the number and call it later, you're honked off enough to write down the license plate number and call the cops.