Not strictly true you can have set ups where pedestrians are given right of way intermittently. You can even make them smart unlike our ancient timer based systems.

I was basing this on the presumption in the comment I replied to that it's not safe for pedestrians as a standard no-lights circle (not that I necessarily agree with that), and thinking more along the lines of Dupont/Logan where there are light-controlled xing areas inside the circle between the corners, allowing peds to move around the circle and into the common area in the middle.

> "This circle has a series of lights, which effectively kills any chance of it being a true traffic circle. ..."

But is it better than an 8-lane 4-way stop light?

> " This also makes merging into the circle difficult, because given the light cycle the circle may be filled with stopped cars which often create their own lanes."

The in the dc examples, the inner/outer lanes are physically separated so this doesn't happen.

Another thought would be to let ped x-ing buttons control the existing lights one block out from the circle, to stem the flow of cars long enough to cross without snarling the traffic already in the circle.

A lot of the roundabouts in the us have traffic signals. Shit many don’t even have lane dividers