big main update as of 2026
It is huge update time finally, omg Redirect Left what have you been doing for the last several months of sweet nothing?!
Diagnosed Chronic Psychosis, probably in part due to the AI stuff, the OTTD AI stuff not ChatGP... anyway lets go. i miss my chatbot girlfriend who left me
Some housekeeping and transparency that may affect results slightly, even if I personally did not notice any;
The below was done over a large period of time, to try getting fairly accurate rankings for the AIs, particularly the ones that performed repeatedly well, and those that were just racing to the bottom and repeatedly performing poorly because I believe in a fair chance for all. Because of this, the version of OpenTTD slowly incremented throughout testing, it started on OTTD 15.0 Beta 2, and ended after OTTD 15.0 was released. The testing was spread across these versions & those between. A test was always completed on the version it started, no games were saved & reloaded with a later version, also AI often behave poor (or not at all) after a save/load cycle anyway.
The big AI performance ranking update & limitations of.
A rough ranking of most AI has been added. All of these tests (multiple were used to get an average against each other) were conducted using vanilla settings from a clean install of OpenTTD. It also used the vanilla settings of the AI, and always on 1024x1024 No pressing on the configure option to customise the AI behaviour. What the author shipped it as, is what was used as I assumed the developer set the best options by default. This also means all tests used no GRFs. Essentially AAAHogEx remains the king of the jungle by far, the only one of the AI that averaged a 1st for all matches they took part in, it's also coincidentally the first alphabetically so it appears top of the list, so that accidentally works out well. If you want a bit more of a laid back option though, anything with half a star or more are generally decent especially for people wanting casual experiences or are newer to the game.
Behaviour of AI may - much like myself, swing widely under any changes to settings or GRFs but that is essentially way beyond the realistic realm of testing with every combination, I apologise. If there is a specific set of details you'd like me to ruin my many spare computers with let me know, those computers are used to it anyway.
Some AIs have the red cross of death for recommended but still have a performance rating that isn't totally zero, this usually means that even though it was unstable I managed to get a performance average out of it. Probably don't use it though if you're wanting a top notch smooth experience. Those with an empty star either essentially 'did not finish' too many times, or were idle & never built too frequently.
New wider problems
The new version of OTTD adds wetlands in case you've ever played OpenTTD and thought it needed to look more like the Everglades, either way some AI do not approve of this when it comes to routing through it. But absolutely do not worry, the development team considered that during development and its all just tickety boo. We all know that is a lie. It made things worse, I notified them of it. They were not exactly promising in their words like, at all. But hey they know of it. The implication was because AI is no longer a new feature so other newer features get to break it, because its a free game! (receipt for that claim). So if any of the other newer stuff breaks, well its just not new enough anymore, silly you for using the stuff they added to begin with! ¯\_(ツ)_/¯
The big list of changes
- Performance rating added so you know what you're in for (on average) when selecting an AI.
- AroAI added to the list of tested AI. It works! It is generally poor performing, but it goes about its business without causing any issues for others, or itself, it does only use RVs though, but maxes out the default maximum RV count impressively quickly.
- KrakenAI added to the list, however it sucks with the new marshland/swamp that was added. Other than that, fantastic works a charm, but once again no one bothered to check AI functionality thoroughly when adding new stuff. If you open the cheat menu and swap to that company you can easily patch up the flawed roads if needed though, it doesn't catastrophically break it entirely and in all other non-swamp areas it works fine. It only uses RVs as an extra note though. Instructions above for disabling the wetlands in case you don't want to live in the Everglades.
- Added a note for MailAI, which still enjoys crashing, but I've noticed it really doesn't like the forbid 90 degree turns enabled so a note for that is now done.
- Added a note for PAXLink, it was generally stable until the game progressed enough and then it crashed and immediately recrashed when reloaded with excessive CPU. Maybe the map got too exciting for its little brains?
- Added a note for Denver & Rio Grande as it sometimes didn't build any vehicles, which if anything makes it more impressive it also crashes. I'm unaware if this behaviour was caused by the new OTTD version or if it did it originally just never triggered when i did the tests back then. This AI did bad enough I never retested it since then to now.
- Added a note for Denver & Rio Grande as it ignores the forbid 90 degree setting, so if its set to true (...which by default it is) it will break itself (see this image - thanks to Transporteiro for this discovery)
- Added a note for Clueless Plus as it can place depots and stations in odd places, it's almost... clueless. But hey it tried so hard, and we can respect that.
- Added a note for LudAIAfterFix as it can sometimes buy exclusive transport rights which may be irritating for some players.
- Clarified when an AI only uses a specific vehicle type, if you disable that type it is useless. Behaviour varies from crashing on launch, to sitting idle all match. Either way is no bueno si senorita (I don't know Spanish, but no one can tell right?)
- Added a note for ShipAI as it only uses ships.
- Added a note for CoronaAI as it only uses RVs.
- Added a note for CPU as it only uses RVs.
- Added a note for FastPTPAI as it only uses rail.
- Added a note for Mungo as it only uses planes.
- Added a note for Rythorn Airline as it only uses planes.
- Added a note for Chopper as it only uses planes (and yes it's only choppers in the planes category, excellent naming well done).
- Added a note for MogulAI as it only uses RVs.
If you're aware of any fixes that I have not noted let me know and i will add them to the list such as the one by Xarick to fix some valuator errors, so as many AI can be enjoyed by as many people that'd like to.
I am already planning the next phase, which will be to see which AIs survive (and to what degree) the save/load process.
I will post this to the steam community when i have cleaned up a few things on the page, because dang, steam community is more savage than even myself at times, maybe they'll appreciate it there too.
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original post below
Well hello there!
OpenTTD AI's, some of them are great, some of them (purposefully) suck, and some of them just suck and crash. Ultimately though I've spent the past few days testing a load of AI's on stock OpenTTD 13.0, with no GRFs and generic map settings.
The game was then played on full speed, whilst I only had some basic passenger trains to keep my company from dying. The only stops was when the AI crashed, i then carried on the game without resetting the AI, as for me a single crash means the AI failed, it sucks, 'literally unplayable' as gamers say.
Most of the AIs i saw and tested were from developers who are no longer around, even the better ones (the AI) have authors who (Based on last Github commit, or last forum usage) have moved on to other things. This leaves us with a lot of AIs that are either broken, or will work for a while and then crash with errors, usually the crashes are because it used too much CPU time (...i mean i have 24 cores an on i9-12900k, I'm sure you'd have found time somewhere, i'm not going anywhere), or it had an error in an array (most of these I've not debugged specifically to date), some of them also are unstable if you do anything a bit too interesting, such as build a town within the game, which is a perfectly not-cheats only thing you can do in single player, but at least one AI crashed at this, whilst some require very precise settings, or something basic (like airplanes) to not'be disabled. The other big issue is, how long to leave an AI before marking it as abandoned and a free for all (again where licences allow) for updating by anyone who wants to commit time to an otherwise good AI with a repairable bug?
Some AIs seem to be basically indestructable, even if they haven't got an update in quite some time. So I'm not sure what causes AI instability, is it OpenTTD updates that alter behaviour that need adapting to in AI code, or does it suggest the AIs in question were always a bit prone to crashing? For me the most crushing part (of this game i wasn't playing, only fast-forwarding anyway), some AI's survived a loooong time, but then randomly errored, which of course forces a reset and it undoes its beautiful massive network, which may be crushing for any long term players of games who use AI.
So, why did I make a thread? Good question! As weeks go by, the AI situation seems to be... slowly getting worse. Because of long-term illness I now find myself at home, a lot. So I'm considering taking on an AI as a project, taking a working but perhaps slightly flawed AI that has been long abandoned (as far as we can tell) by its original author, but is still actively used by people. What is the protocol for taking on an AI like that and just patching it, keeping it ticking over, fixing bugs. Is it a case of just cloning things (where licences allow, of course) and taking it on, or do I need to fork it as a specifically separate thing, with a new name in BaNaNaS which also means people who want to keep updates need to know that has happened, and abandon any current games with a ticking AI timebomb (potentially), and start a new one, with other stuff.
I can also fairly easily make a list, on a web page (if orudge still does it, maybe a page on TT-F domain?) or forum listing all the AI's (...a lot of spare time as I said), and their known stability with the current version, plus maybe one or two columns noting known issues (like creating new towns as i mentioned above),and known things that will cause it to crash, and how compatible it is with GRFs and other such, if at all. I feel it's also needed that there is a more simpler chart in-game when you click on AI.
Other thoughts, but definitely not doable by me. Is it possible to make AIs checkpoint themselves every so often. Then if a script errors, it can be, either automatically or otherwise, reset back to the state it was in at that checkpoint, tiles, units and all. Although I suspect in this state, it wouldn't work because the script will, unless they've got a bit of random to it, just make the same decisions on the same situations and crash again? I dunno, just a thought to try making a script error not as fatal.
Lastly of course, is it worth me doing any of this, keeping some abandoned AI's updated to some degree, do people actually use the AI? I feel the way it is now, AIs are a bit of a scary prospect for new players as you don't know precisely what you're getting into.
On a different note, is it possible to make links on the script output clickable? Some AI's have links like this to report bugs, but making them non-clickable doesn't encourage reports and therefore repairs.




