I would do everything possible to avoid this UK Round-a-bout — nothing Magical about it having three concentric lanes just in its inner loop! =P
Ours is much simpler, with a round-a-bout on either side of a regional highway. One of the difficult parts about it is everybody is already jacked the fuck up (on account of 2 of the 5 input/outputs being extremely steep grade to enter/exit a river-crossing, with speeds averaging 65-70mph ["55mph" posted, oklol).