Picking up where we left off, the reason people sit next to the median with their asses hanging out in traffic has two components:
1.If I can't see it, it isn't there.
2.There is nobody in the entire world but me.

Both of those rules come into play when the ass is hanging out from the median, but I've seen lots of both of those. Occasionally you'll see someone stop, just plain stop, in the road, as though a)there's nobody else in the world and b)they can't see the people about to crawl up their tail pipe because their busy inspecting their fingernails for fecal matter or something.