Cities: Skylines

Cities: Skylines

4,196 ratings
Roundabout Builder
File Size
0.100 MB
Jan 15, 2019 @ 9:24am
May 14 @ 2:30pm
38 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. Fine Road 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, make sure it is placed in a folder called 'FineRoadTool'.

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
Adjust Pathfinding Mod
Undo It! Mod
Extended Error Reporting Mod

Please leave any feedback below!
Popular Discussions View All (15)
Jul 30 @ 5:34am
PINNED: Bug reports
May 20 @ 11:17am
Jun 8 @ 3:40pm
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LemonsterOG Sep 19 @ 1:29pm 
@i-smell-like-poo -- I'd rather have the use of airport roads and simply use the key binds to access the other mods, rather than do without an important part of creating airports. I guess it's a personal preference.
i-smell-like-poo Sep 19 @ 12:07pm 
Hyperspeed1313, lol, I just figured this out too.
i-smell-like-poo Sep 19 @ 12:05pm 
For those that have this mod disappear, shut off the Airport Roads mod if you have it. This solved the problem for me.
Hyperspeed1313 Sep 19 @ 11:47am 
@BraccX do you have the Airport Roads mod? I've found that the Roundabout Builder button disappears if I've used Unlock All AND have Airport Roads turned on.
大朵拉[Big_Dora] Sep 13 @ 9:04pm 
BraccX Aug 20 @ 7:15am 
Great mod! Only issue is that the icon disappeared. Bit annoying since I sometimes forget the shortcut.
TurtleShroom Aug 11 @ 1:49pm 
Roundabouts were designed by Satan. I fear them as much as I despise them. They should be illegal. This tool is perfect for when I want to torture my Citizens. :lunar2020moneyrat:
uziwonzanobi Aug 9 @ 6:59am 
i used this for 2 weeks, awsome mod, then it disappeared! tried restart, unsuscribe, no luck
MrKopter Aug 6 @ 12:47am 
Great tool that I use a lot - A Top 20 mod
Bernie Jul 30 @ 6:28pm 
Such a simple yet usable mod that just works.