This is a Google Maps street view of I-66 heading west, just past the Teddy Roosevelt Bridge and immediately after the "Lane Ends Merge Left" sign.
You see that dark Honda in the left lane about to drive over that dark line?
That driver is about to have a boneshakingly bad time.
A closer look shows why:
See that ridge in the road patch that looks like a very badly designed speed bump in the middle of the highway? That's exactly what it is.
It's been around for at least a few months. I first discovered it at night, coming back from a concert in DC. Since I don't drive into DC as much as I used to, I'd forget about it for a while, and then the next time BAM.
If I can figure out who to complain to, I'm hoping they can fix it; if not, we'll need to come up with a nickname for it, like Toronto's former "Humber Hump."