[shiroiushi]

>Even if they don't prevent all collisions, they turn T-bones into glancing hits

No, they don't, at least not in America. When you let American traffic engineers design a roundabout, you get this: https://www.google.com/maps/@38.8643875,-77.2755474,583m/

[esskay]

Nobody in their right mind would ever class that as a roundabout. You dont stick a high speed road directly through a roundabout.

An actual roundabout DOES solve the tbone issue.

[lozenge]

That's... Not a roundabout. It would be funny if it weren't so scary.

[ColinWright]

As others have said ... that's not a roundabout.

Here's one of my favourite hybrid "roundabout" junctions:

https://www.openstreetmap.org/search?query=Boughton%20Heath%...

[shiroiushi]

>As others have said ... that's not a roundabout.

American traffic engineers would apparently disagree with you.

[ndsipa_pomu]

That looks like a Hamburger Junction (or roundabout interchange https://www.roads.org.uk/interchanges/roundabout-interchange).

I think they're a bad design as they encourage drivers to go fast with the sweeping corners etc. Ideally, a roundabout should be designed to slow traffic joining it to reduce collisions and their severity. Trying to keep vehicles moving quickly at junctions is just asking for trouble.

[USiBqidmOOkAqRb]

It's disheartening to see that much parking place around that spot.

[offices]

This reminds me of this oddity in Nottingham:

https://osm.org/go/eu8S4TeKc?way=50459468

(right-hand drive)

[123pie123]

similar one here, but with added lights https://www.openstreetmap.org/#map=18/53.479432/-2.281970

[shiroiushi]

The one I linked to in Fairfax County VA also has lights, though it might not be obvious from the aerial view. It's really a disaster of traffic engineering. It's probably the most complicated intersection I've ever driven through.