Just figured the game could run better when other vehicles you're not focused on are optimized. Maybe vehicles you're not driving/focused on have much lower quality interiors and tinted windshields. Or maybe textures are also lowered. I don't know, just ideas to make it work better.
Tbh textures are not what hits hard mostly, lower quality goes to Lod models and draw distance, if you mean low poly cars, I don't know if that possible here with non-environment object
