^ That must be new since I left the area, because there were NO DC milemarkers on the bridge at all when I lived in Huntington.
The WW Bridge milemarkers appears a short time after the bridge redo was completed. The catch is that the DC milemarkers look EXACTLY like the MD milemarkers... what gives it away is:
1) heading from VA to MD, you get mile markers up through 0.8 (IIRC) and then the next marker is either 0.2 or 0.4;
2) heading from MD to VA, the milemarkers descend to either 0.4 or 0.2 and it's obvious that 0.0, which is not posted, is in the middle of the bridge, which is followed (IIRC) by another 0.8 milemarker, then 0.6, 0.4, possibly 0.2, and next you see a VA milemarker with 177 point something.
That is, however, all irrelevant to the GW Parkway. I haven't voted in the poll because I don't have a strong opinion either way.