It's DX11. I haven't even tested SGSSAA because I'm already down to 5 fps. I only have sli 470gtx's so I'm limited to 1.25 vram : ( If you can figure anything out it would still be awesome though!
Ah well since it's DX11 we really don't have any options then other than trying to appeal to the developer to implement better solutions. Because the game really needs it from the looks of it. (Also could probably use some filtering for the real time reflections on the cars as well)

Nvidia doesn't have any support built into the driver really for DX11 AA Functionality beyond some basic stuff for very specific games. And most of those are early DX10 games that don't really work all that well.
Currently stuck with only good support for DX9. Since the game is DX11 we are SOL aside from trying to enhance the in game MSAA with SGSSAA, which usually doesn't return great results in most DX11 games.
I just realized you're Mr Bonk from Guru3D (aka, the SGSSAA king).
Listen to this guy! He does good stuff.
Yeah, same guy (I use the same avatar so some people who come to both G3D/3DCenter know it's me).
The more games I pick up that are DX9, the more I test to figure out solutions for AA/SGSSAA. Especially for games that don't have known solutions or use out of date solutions from a few years ago. (IE: Games that use lower quality functions for AA compatibility or use the bit that disables AA on the primary flip chain and compare them to see if there is any issues or glitches with things like the AA-Fix or other things. A current example would be Sniper Ghost Warrior. It's one of those games that needs the AA fix to solve glitches. With the old flag AA would not work with the AA_fix enabled)
One day I would hope to find solutions for every possible game that runs in DX9. It would be nice to get it working for games that are currently impossible to do so or have severe glitches, but that's a pipe dream at this point. (IE: GTA IV, Binary Domain, Legend of Grimrock, ArcaniA, Legends of Dawn,Dead Space 2)