When I break out the road bike I find that riding the edge makes me a mailbox! Drivers assume that I am part of the scenery and squeeze by even in the face of oncoming traffic. They will do this at speed more often than not.
I live in rural CT where guard rails squeeze the side of the road every few hundred feet for wet lands or other obsticals. In these places I move off the edge to discourage the high speed centerline crossers but I also use a mirror to adjust my speed to attempt to cross these areas in lighter traffic flow.
I did however have the mirror smashed off the bike by a school bus that appeared to be doing 60ish in a 50 zone while passing me on the wrong side of the centerline before he got squeezed back into me by an on coming school bus!!!!! All I could think of at the time was the opening sceene from the original Star Wars. (lets see how your memory works) There was just this huge yellow wall going by forever.
At certain times of the year (major drunk holidays and near graduation) I just leave the road bike home and go out on the trails.