A highway interchange that allows vehicles to change from one roadway to the other without requiring any left turns or crossings. Seen from the traffic chopper, it resembles a four leafed clover.
Sometimes they came with
electronic signs that light up with the words "
TOO FAST" if you take the turn at
excessive speed. You don't see these much anymore, probably because people thought it was a
challenge.
Not me, of course. Ahem.