The recursive design allows you to go the "wrong" way around the "big" roundabout.If you want to take the exit immediately to your right, the "single huge round

The recursive design allows you to go the "wrong" way around the "big" roundabout.If you want to take the exit immediately to your right, the "single huge roundabout" design would require you to go almost all the way around to reach your exit. The recursive design allows you to take the third exit from the first two mini roundabout. Sorry if that's unclear, it's a bit tricky to explain in words. Another advantage of the recursive design over a big roundabout is that it keeps traffic speeds slow, so collisions are much less deadly.