Was it Nascar Racing(Sierra/Papyrus) that provided the AI with canned responses so as to 'appear' human? Unfortunately they only gave them a handful of messages so within a few minutes you could identify every non-human participant.
I've been good with AI, I've only had two problems: - AI rain tires: when a race starts with rain, sometimes the AI starts with slick tire, or during the race, to the pit and back with slick tire in the rain, then to again to change to wet, never correct that. - Full Course Yellow: On some tracks, the line followed by AI on the yellow flag is crazy, they are making curves in the middle of the straight, leaving the track and I never managed to correct this by moving AIW. I have picked up clues and corrected the race line by adding the BLOCK line and it has been sensational to run offline. You also need to tinker with the player.plr and activate the options where AI uses multiple lines during the race, including the line of defense, otherwise it will only continue to run as simple as rFactor 1.