Glen A. Larson (Creator of Knight Rider and Battlestar Galactica) stated that the scanner is a nod to the Battlestar Galactica Clyons as well as the sound effect of the scanner too.
I have an all black police Ford Taurus that has the AP system still in it and I’m trying to program Knight Rider sounds. I also have a red visor light that does the scanner pattern like k.I.T.T.. it’s not the Trans Am which I love very much but hard to find, but this car looks sexy as hell as K.I.T.T.