Cities: Skylines

Cities: Skylines

577 ratings
Traffic Manager + Improved AI
File Size
0.612 MB
Aug 11, 2015 @ 8:20pm
May 29 @ 1:03am
16 Change Notes ( view )

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Traffic Manager + Improved AI


This mod combines the original Traffic Manager by CBeThaX with Improved AI by jfarias. Additionally, it provides the intersection editor tool from Traffic++ for fine tuning of lane arrow assignments. This tool is activated by alt-clicking on the "Change lanes" button in the TM menu. The Traffic Manager features work as they did in the original mod. I will add detailed instructions shortly.

This mod is compatible with saved games produced by the original Traffic Manager. I believe it should also work with the ones made by Traffic Manager Plus, although I haven't tested that. Also, you should be able to use Traffic++ in ghost mode if you need to.

PLEASE NOTE: If you have used this mod in a saved game, then deactivated it and made changes to your roads, you may get errors when reactivating the mod at a later time. To resolve this, check the "Ignore saved data on startup" box in the mod options before loading your game. More details on this to follow.

The Improved AI portion of the mod has four significant operating parameters. I have exposed these in the AI panel so you may configure them to fit your needs. The parameters are as follow:

congestion cost factor
minimum lane space
lookahead lanes
congested lane threshold

When there is less than m_minLaneSpace available in a lane, the AI considers it as "congested" and multiplies its cost for path finding by m_congestionCostFactor. The default values are 5 for lane space (from the comments, this is for a "car of length 5" but the units are not specified) and 3 for congestion cost factor. From my experiments, it seems traffic behaves much better with values around 13 to 15 for minimum lane space and 3 to 4 for congestion cost factor. I am currently getting very good results with a minimum lane space of 13 and a congestion cost factor of 3.7. With these values, I have observed excellent lane usage overall.

Increasing the cost factor too much is not a good idea. It will, in particular, wreak havock in your bus lines, as busses will take insane detours between stops to avoid congestion. In fact, a neat experiment to try is to fiddle around with these values with the public transit info view on. You'll see right away the effects on the path finding as lines will adjust soon after you change the values.

The number of lookahead lanes and the congested lane threshold control the depth of the search for the optimal path. Increasing the former while decreasing the latter will trigger more frequent searches and generally result in a better path, at the cost of performance. Refer to the discussions section for a more detailed explanation. My machine is a tad below the minimum requirements to play the game, so I had to tweak these values accordingly. Thus, for a low-end machine, I recommend setting the number of lookahead lanes to 3 and the congested lane threshold to 2. With these values, a city of around 100k population is playable with no noticeable loss of performance and excellent traffic flow.

One final note. All credit for the original code goes to CBeThaX and jfarias. These guys have produced some outstanding work indeed. All I've done is make their code cooperate to produce something I believe will benefit everybody. Also, this mod would not have been possible without the use of cope's essential detour code.


P.S. You must deactivate all other versions of Traffic Manager as well as Improved AI before activating this mod.

Source code available here.[]
Popular Discussions View All (22)
Jul 12 @ 9:47pm
Chris The Beast
Mar 6, 2016 @ 7:44pm
[BUG] Tram track
Aug 20 @ 12:33pm
Existing / working Nodes disappearing
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mongolteiko Sep 1 @ 2:04am 
What you said.....that road has priority over the side road. @ Narobic.
In Germany, traffic lights have them too incase they fail, and every side road
has a give-way and main road the diamond sign....helps legal cases.
NarobicYT Aug 31 @ 10:33am 
What is the orange and white diamond priority sign?
BloodyPenguin Aug 20 @ 2:35am 
@Darkangel Firstly, pathfinding code is highly coupled with traffic related code, and it's not possible to have a separate vehicle AI mod that wouldn't conflict with whatever TM version. Secondly, President Edition is not a better version, it's a different version with more features (and it also features its own take on improved AI). So you better just switch to TM:PE.
Don Slade Aug 2 @ 9:34am 
Can you actually copy the lane connector setup from an intersection to another? I dind't find it in the manual but think this would be a very helpful thing that would save lots of time and boredom
Simlex Jul 22 @ 6:45am 
hi, all trucks are despawning and only the trailer is driving around the street. Is there a FIX for that?
Darkangel Jul 10 @ 5:14am 
Cant we just have the improved AI without the traffic presdient which will conflict with the better presdient edition version is it that just to bloody simple??? We only need better pathfinding to give an iq to traffic so they dont keep taking the same roads as every other sheep otherwise i need to constantly make districts with 'old town' or ban traffic policies or use vehicle restrictions for the roads etc.
Darkangel Jul 10 @ 5:09am 
is it compatible with pres edition or will it have errors with it?
Freak Geniuz Jul 9 @ 10:30pm 
@MGGebriel I'd perfer using the president edition
MGGebriel Jul 9 @ 4:22pm 
Does anyone know whether this contains all functionality of Traffic Manager: President Edition? Which one should I use?
code1001(loljk_crew) Jul 9 @ 1:13pm 
it works well