It's not really made clear above, but the idea is to make passing easier by implementing this split wing.

For those of you who think rear wings are there to make your Honda look cool: It's back there to create downforce > tire grip > the ability maintain as much speed as possible through a corner.

The FIA has been talking about this since before the F1 season ended. Assuming that this concept has been tested to some extent (confirming the theory is sound) before being introduced, I say let's do it! As it is right now, two closely competitive cars have an excessively difficult time passing. The car in the back giving chase must maintain a great cushion from the lead car because it needs clean air over its wings. When it's time to attempt the pass, the car attempting to pass has too much ground to cover. The only time it can be done is when the tail car has a much more talented driver ... like when Kimi passes Fernando