Robert, these aren't "superstreets."  These are "jughandles".  Obviously you have no experience driving in New Jersey where jughandles proliferate.  It's a freeking traffic nightmare.  Sometimes you really have no idea what you are talking about.  Stick to physics.

The best system I've seen are feeders along highways in Houston on the newer highways (example, around Sugartown) where there are left turns under the highway incorporated with uturns.

this superstreet is called a round-a-bout!  Roundabouts are more efficient than a traffic signal and when the power goes out you can still travel  The other big benefit is they act as natural speed limiters!  Impacts that do occur in them are less serious, because they are glancing blows, never head ons or t-bones