I had a game that was similar to this. Crash 'n Burn for the PS2 had Kamikaze races where half the players would go one way, and the other half would go the opposite direction. This reminds me of that. But these scenarios has a few problems:
1. The dust. My frame rate died when the cars would kick up the dust, and that was the disadvantage one. I suggest to have it on a asphalt road.
2. I was disappointed to only see 1 other AI car in the SBR4 scenario. Add at least one more.
2. I know the AI is out of your control. But I suggest that you make a scenario on what I described above. If you have one half go in one direction, and the other half go in the opposite direction, this will cause more mayhem, and they won't get stuck turning around since they aren't turning around.
I did enjoy these scenarios, but it's does need a bit of work.