I would like to suggest implementing reverse Z depth to mitigate z-fighting visual artifacts that can be observed in the game.

For the non-technical people reading this, this simply means less flickering of geometry that is very close to other geometry: concrete objects in custom layouts, lines and arrows on the ground (which seem to be placed about 1mm over the ground) and other such graphical issues.

To give a few actual examples:

• South City, behind the grand stands across the main pitlane at /cp 20174427 4722383 9957501 19884 15474 0.0 60.0 - any time you move the camera, you can see the arrows flicker.
  
• Concrete parts: place a few concrete slabs next to each other, with some intersections, and you will also have severe flickering.
  
• In the Laurent Coil Cup mod I'm working on, I chose to have the sunshield as separate geometry above the windshield, because I need some of the windshield's geometry to be double-sided (the black part on the edges), and I also want to use the same windshield for the non-cup version, which doesn't have the sunshield; I need to separate the geometry by over 4mm to stop z-fighting from being visible in long-range shots, but in closeup shots you can actually see that offset.
  

This is currently alleviated somewhat by offsetting the geometry, that's why the arrows and other markings on the ground are slightly above it (if you go to /cp -6264565 6547061 674862 -30063 4209 0.0 60.0 in Blackwood, you can actually see that offset for the pit boxes through the camera's near clip plane). The racing line darkening, as well as the thinner lines visible on Blackwood especially, are actually offset by several centimeters! (/cp 756993 -11233401 -6824 -3991 3694 0.0 60.0)

There exists an efficient method to fight this, called reverse Z depth, which I believe is not currently used. Here are a couple links to articles talking about it and its implementation: NVIDIA article, example and additional links
This technique should have little to no performance impact, but should greatly improve the z-depth sorting, which would reduce graphical glitches and maybe even allow for less geometry offset.