There are actual roundabouts in DC, but typically they don't have names.

A "roundabout" is a kind of intersection. One characteristic intersections generally have is that traffic should not stop upon entering the intersection. The picture you've linked is a circular road, with a half-dozen or so individual signaled intersection along it.

While roundabouts do have center islands, sometimes even with sidewalks, pedestrians generally are not expected to ever walk there. For the same reason as outlined in the previous paragraph: getting pedestrians safely to the center island would require interrupting the flow of traffic inside the intersection. Walking by some roundabouts with built-up center islands, I sometimes wonder how long someone could camp out in the thicket without ever coming within 20 feet of another human on foot; the islands are no-man lands, very unlike the satellite image you link.

I can reasonably envision a pedestrian signaled roundabout, where the crosswalks at the entrances and exits to the roundabout are all signaled. I have not, to my memory, ever seen one. And, again, I think the reality of their rarity speaks to my original point that pedestrians are, as in all US traffic design, always an afterthought.

I was in London area in the early 90's and they had stoplights at roundabouts that were high volume. If I remember right, a person told us the lights are only used at certain times of the day.