At the boot up of the game, if you navigate to here :

Test Menu >> Game Assignment

You can set the Difficulty setting to one of four options:

Easy
Normal
Hard
Hardest

Something that I'm unaware of is if there's a strict standard on setting on what difficulty of AI to use on speedruns.

For me, I play on the Hardest difficulty (cos IDK I wanna punish me?) and that's part of how I got my recent time of 3'45"737 on the Expert - Manual category.

But what about the others? What if I'm playing on Hardest and it's hindered my chances on getting good run while others are in Easy, Normal or Hard mode and having the greatest, most unbeatabe runs of their lives (depending on if it's set before the run was ever recorded or by the manager of the arcade machine that you can't just sneakily change on the fly)?

I haven't got time to try out the different Difficulty settings and compare AI patterns on which gives the best/worst chances on drafting longer for higher speeds & which gives you the best/worst chances of not having slowdowns from bumping into AI cars at the starting line - or the setting does nothing and AI patterns are just determined by RNG.

Just a thought I have. This hasn't yet been mentioned in the rules of submitting runs here & I wonder what the community thinks of this.

As far as I know, the difficulty setting only affects the timer. The AI itself isn’t influenced by it, which means the difficulty you choose doesn’t really matter in the end. (I read about this years ago so i'm not 100% sure).

Hmm. Alright. Thanks.

I guess I'll just keep submitting my runs with my difficulty set to HARDEST if this is the case

I'd be curious if the easier difficulties affect the AI. Slipstreaming is a pretty big factor so I'd imagine if they are set to hardest then (on paper at least) there would be more of them ahead of you to stream before you hit pole position, no?