The right of way regulations. Traffic inside the circle does not have the right of way, sometimes, but then sometimes it does. Every continous line in there marks a "you have to stop for incoming traffic".
It's most easily seen if you're approaching on the leftmost lane from the South-West. Following the markings, you may only exit to the South East or the south. Or be stuck in an indefinite loop.
Then what would it make it a propper roundabout?
The right of way regulations. Traffic inside the circle does not have the right of way, sometimes, but then sometimes it does. Every continous line in there marks a "you have to stop for incoming traffic".
It's most easily seen if you're approaching on the leftmost lane from the South-West. Following the markings, you may only exit to the South East or the south. Or be stuck in an indefinite loop.