I don't understand how everyone knows what the commenter is referring to when it took me forever. I figured he was referring to the "dents" on the shoulder, which I thought were rumble strips.
Like GP, I was also confused. I think this is because HN links to a comment featuring a streetview photograph. Until I saw your comment, I didn't really notice that the article should have been linked to the very first post in the thread, which does clarify the question.
