[xamolxix]

> It's supposed to be "you can't just..."

Honest question, why can't you? Is it disallowed by law?

[cinntaile]

I don't know anything about this field so I can't answer that unfortunately. If I were to take a guess, I'd guess it's for (real or imagined) safety reasons? Roundabouts where you can't go around again aren't that common here though.

[foxyv]

You will see a lot of "Shepard's Hook" roundabouts in the USA to prevent people from going around again. I personally don't know why.