Excuse me replying to you with this random question, but i'm curious! Currently BeamNG seems to spawn in cars about as fast (or faster) than some other games do so at a vehicle selection screen, which is awesome considering how the cars are made in this game. How do other games tend to spawn and hotswap traffic in such a way that it causes no slowdown? do they already exist in the game world out of site somewhere?
I did figure out one thing. If you have the "Better Sounds Mod", disable or remove it, as it is currently causing a conflict preventing traffic from working. Still tracking down other causes of traffic errors.