You can actually screw them up: by our house (in California) they replaced a 4-way stop with a roundabout with no signaling on 2 of the ways, and a stop on the other 2. An absolute disaster, as the 2 ways without the stop assumed they had the right of way over people already in the roundabout.
After the neighbourhood complained, it's now a roundabout with 4 stops (not ideal, but not dangerous either).
This. If it's not the case that all entrances have a Yeild (what we call "Give Way" in the UK), it's not a normal roundabout.
The feature that seemed to be missing from the roundabout in the original post was any kind of signage. Normally in the UK, roundabouts have a sort of map view as you approach them, then on the islands are signs telling you where to exit.
I can confirm these are dangerous. There are several of these in Berkeley and I got knocked off my bicycle on one of them for exactly the reason you describe.
I am from the UK and it makes me wonder why road design in the US is so bad. Just one minute of thinking about this as a lay person would reveal the problem with the design.
Is there some structural reason in the US that would cause it? Perhaps some lack of standards or approval process? Perhaps iteration speed is slower so they don’t get better? Some other incentives going on?
My personal hypothesis on this is that the worst 5% of Americans is likely both dumber and more sociopathic than Europeans, and the behavior of the worst drivers is what creates a lot of traffic and road accidents. If that is the case, you will not have the same kind of design that works in a high-trust, more cohesive society.
What should I imagine when you say roundabout with 4 stops? Isn’t that just an intersection that looks like a roundabout without functioning like one (entirely negating the point)?
I guess drivers just don't realise they need to slow down or give way to anybody unless there's a stop sign, traffic light or they're turning into a different road.
Surely drivers know what Yield means though right? I guess the US might need yield signs at a roundabout given not all drivers will get the basics of how they work. There should never be a stop sign on a roundabout, the whole point is you're supposed to be able to keep going without stopping at all if theres nobody coming round it.
After the neighbourhood complained, it's now a roundabout with 4 stops (not ideal, but not dangerous either).