It has always made me wonder, so I think I'll ask the question. You are driving at the speed limit or higher, a car passes on your side of a four lane highway, and for as far as the eye can see there is no other car in the passing lane ahead of the passing driver, and no one overtaking him. Why do so many people think its SOP to cut back within a car length, or two immediately in front of me ? These drivers could drive for ten minutes in the passing lane and hinder no one, or overtake no one, so why the obsession with cutting back in front at a distance that immediately makes me an unwilling Tailgater. Sometimes these genius's even slow down, forcing me to pass if I want to maintain my speed. Is this a mental disorder of which I am unaware ? Can anyone suggest some valid reason for such behavior ? The Presence of a Prius seems to trigger 'Their Need to Exceed', so cars you may have passed will often speed up so they can now pass you. The Cruise Control makes this aberrant behavior very noticable.