Meh, the AI in this game is set to let you catch up if you happen to go off the road, but if you take too long to pass them they will return to their pattern and you will not catch them again unless you drive the wheels off your car. I have witnessed the AI in GT6 do a lot of things, but they are better than the idiots in GT5. Sorry but GT5 AI get's cold feet the instant you get anywhere near their quarter panel and they delay getting back on the gas for a considerable amount of time. GT6 the AI rarely if ever does that and they will take an opening if you give them one, I have encroached the AI line and they bumped me but rarely pushed me off the road, I don't mind the bumping. I have never ever since I had GT6 had the AI ram me, I've rammed them by under braking quite a few times but never seen them do that ever.
Some people complain about the AI ramming them I fail to find how this is possible unless you were braking way too early for a corner or you spun out on a high speed area when it's hard to avoid that sort of thing even if you were human. If the AI could avoid you in any situation then obviously that's just cheating. I just don't understand why PD doesn't give us a difficulty setting for AI in single player, I would prefer if the AI would drive tenaciously with any car and not have a few weak AI lumped in with pro driver AI. I hope B Spec is equal parts GT4 and some of that Forza Drivatar, want them to learn on their own and also nab techniques from other drivers or perhaps you can have it use your techniques. How well PS3 copes with learning AI is anyone's guess but it's not like it's totally impossible mainly attack vectors and taking chances and hoping they pay off. GT AI seems to run on a modified physics engine since they seem to retain control of their cars' much better than a human, it's to be expected since the AI knew you were going to come into contact with them and already started calculating the adjustments necessary to keep their car under control. PD could fix that by delaying the AI recognition of the impending contact and not allow them the usual superhuman reaction speed.
In somewhat equal cars the AI is ok, but they are just too clinical when it comes to turns. It's like they are programmed not to push the car unless provoked, when it should be to push the car within limits when in the lead and to defend when another car approaches and to step up it's push within the limits of the car condition. It would be great if the AI learns as you play the game and they get better along with you, they are given risk parameters for weather, tire damage, fuel level and overall car health and that is applied to their position and the overall abilities of the car(PP). If they can get a system that takes that into account to how hard the AI will push in order to move up in positions and ultimately the lead. They could also have a secondary mode when the AI knows they can't win but they won't give up their spot without a fight, I'd love to see something like that implemented in GT one of these days. If I was still programming I would give it a go, but no thanks. PD already have a nice base, they just need more sub routines for aggression and the AI being less timid about cornering. I for one would enjoy close PP races and not the large PP gap from 1st to last and more X2 race starts. When you have a close PP race that requires your full attention just to make it up a couple of spots then the AI is done right, mind you without cheating that is.