Cities: Skylines

Cities: Skylines

10,005 ratings
Roundabout Builder
File Size
105.472 KB
Jan 15, 2019 @ 9:24am
Sep 28, 2022 @ 5:08am
42 Change Notes ( view )

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Roundabout Builder

This mod automatically builds roundabouts for you. It clears the area of the roads and snaps them onto the roundabout. Network Anarchy is recommended.


Experiencing issues? Reinstall (resubscribe) the mod

If you cannot run this mod at all (icon is not showing and shortcut is not working), you can try Extended Error Reporting Mod and Mod Compatibility Checker to find if another broken mod isn't causing the trouble.
Any ideas how to make this mod even better? Post them to the discussions section.
Did you encounter any odd behavior? Please report it as soon as possible! It may be caused by the new update(s) and I might not know about it.

How to use this mod?

(1) Enable this mod in content manager

(2) When in game, press CTRL+O or click the icon in road tools menu

(3) A small window should appear. Hover over an intersection and you should see a red circle representing the roundabout to be built (inner line of the circle = inner edge of the road and vice versa). Click and the roundabout will be built
If you want to build the roundabout with roads automatically connected, make sure that you stay in the main menu! Don't click 'Free Cursor', 'Elliptic roundabout' or anything

Before building the roundabout
(4) You can change the radius by editing the value in the window or by pressing +/-
(Warning: the road will be very distorted if the radius is too low. You should not go under 15 units)

(5) You can change the roundabout road in the dropdown menu or by selecting the road in the roads menu (works only for one-way roads by default). After you clicked on the road in the roads menu, click anywhere in the window to reselect the roundabout tool

Any time the tool is unselected while the window is open, click anywhere in the window to reselect it.

Check the "Keep open" box so that the window doesn't close automatically when the tool is unselected

TMPE Policies

If you are using Traffic Manager, this mod automatically sets some policies for you. These include: No parking, Priority signs, ability to enter blocked junctions, ability to change lanes at junctions and disabling crossings. You can disable this feature as a whole or allow the policies one-by-one.
Warning! If you use local version of TM:PE, it must be located in a folder called 'TrafficManager', otherwise this feature won't work.

Road snapping algorithm

From version BETA 1.1.0, there is a new snapping algorithm. To change the algorithm go to options.
Standard - Respects the direction of the road when snapping it to the roundabout. Connects it at whatever angle the road is.
Old - Distorts the road, but connects it at 90° angle. More reliable.
Well, I wanted to create an algorithm that would take the best from the methods mentioned above, but for now it turned out to be too complicated. Or I am just lazy.

Tips & Tricks

You can also try Automatic Pedestrian Bridge Builder mod, which makes building overpasses over roundabouts and intersections as easy as two clicks.

With this mod you can create super cool mini roundabouts (common in some parts of the world) as seen on these screenshots[]. Underneath is a standard roundabout with radius of five units upgraded to a highway ramp. Onto it I moved some tiling with Move It because the roads appear glitched when the radius is so small.

Why did the option to build elliptic roundabouts disappear? Elliptic roundabouts are now deprecated, but you can enable them in the options. See this tutorial on elliptic roundabouts[]

Is it possible to build power lines, cable car wires and other structures that are not roads with this mod? Yes it is! Just go to settings and tick the 'Do not filter prefabs' option. Then every available prefab (linear structure) will appear in the menu.

How to build elevated roads? You can force roads to elevated mode by using Fine Road Tool. Warning: If you are using a local version of FRT/RA, make sure it is placed in a folder called 'FineRoadTool'/'RoadAnarchy'.

Important note!

You use this at your own risk! Intended only for flat ground without buildings! Don't use on places like an edge of the map.

Before using for the first time, try it at some place where it can't cause much damage. If you try to break this mod, you very easily can.

Source code & credits

Source code[]

Big thanks to boformer for his tutorials on Simtropolis, to Elektrix from whom I took some source code and for his advice. As well as that, I copied bigger or smaller parts of the code from: Parallel Road Tool by T__S, Move It!, Fine Road Tool and Button shortcuts by SamsamTS, Crossings by Spectra, TMPE and probably others.
Respect to all the boulders without which no roundabout would be complete!

Check out my other work as well!
Smart Intersection Builder Mod
Undo It! Mod
Python Console Mod

Address: bc1qvma38p2fcgle9z0w3dehljjt303r4q2qg89nqy

Please leave any feedback below!
Popular Discussions View All (27)
Jul 23, 2023 @ 1:40pm
PINNED: Bug reports
Dec 31, 2023 @ 5:13am
Error No IUserMod implementation. Every mod must implement IUserMod.
Mar 13, 2023 @ 11:46am
TM:PE Integration
nemash Apr 15 @ 10:07am 
It works all the time for me for a fast solution. But I'm not so satisfied with all the outcomes, since you don't have all roads available in the menu for use. And it do weird things sometimes like it's oval and doesn't fit to ground levels even if it's set. I'm better of constructing my own roundabout.
mr.noname.kingdom Apr 15 @ 9:23am 
anyone got this mod to work?
Smitty Feb 14 @ 4:59pm 
i think i did something wrong now its saying roads will not be removed or connected before it worked fine and i think i messed it up :(
±Sol± Jan 27 @ 12:06am 
a8612a2 Jan 26 @ 2:18am 
good bye
Afrikaan Kommanda Jan 18 @ 10:02pm 
Where is the single lane option? Why is 2 lanes the smallest we can get?
Gaston Diaz Oct 18, 2023 @ 6:32pm 
When I build a roundabout with this tool, cars stop comming from outside ant kills my city.
Does anyone know if there is an updated version of this mod?
groof14 Sep 28, 2023 @ 6:35pm 
when i try to use the mod it says ERROR: No UserMod implementation. Every mod must implement UserMod.
Erikas Sep 25, 2023 @ 12:53pm 
Doesn't work. nice work
Sarayu Sep 6, 2023 @ 5:42am 
잘 됩니다. 감사합니다