lane disciplinarian

Another driver who makes great show of pointing out to you that you are in the wrong lane, or won't let you in when you try to change lane, by flashing their lights, blowing their horn, gesticulating, winding down their window and saying loudly to you that they think that you indulge in self-abuse etc.

I was in the wrong lane but when I tried to change some sanctimonious lane disciplinarian blocked my path