This occurs when someone who is driving on the freeway consistently drives on the white reflectors to guide their path as opposed to driving in the center of the reflector lines. Much akin to a blind person running their fingers over the special bumps to read something.
Hey are you gonna stop driving by braille or what? It's giving me a headache.
A combination of two Saturday Night Live alum movie quotes; zang meaning "excellent" according to Mike Myers in Wayne's World, and the redneck dang that David Spade says in Joe Dirt when he thinks something is cool. More punctuated when said in a southern accent like David Spade's character Joe Dirt, better punctuated when the 'a' sound is dragged out and given an extra syllable.