Cities: Skylines II

Cities: Skylines II

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The Ultimate Traffic Guide
By hr kartoffel
Got a traffic jam you want to fix? Well you've come to the right place! Whether you're new or experienced, this guide is made for you.
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Update 30 November 2024: New interchange has been added! Thanks to the person who recommended it in the survey. Be like them, and help me out in this survey! [forms.gle]

Introduction
Welcome to the ultimate traffic guide for C:S2. If you're reading this, you probably have a traffic jam in your city that you want to fix. This guide is made for both new and experienced players, so hopefully this guide can help you out.

I'm a civil engineering student, focusing on city planning. I learn best by explaining concepts to other people, and you guys are the perfect audience, so that's why I created this!

To the right, you can find the guide overview, and the different sections. I highly recommend reading the "Basic Concepts" section, as that will be the backbone of the rest of the guide. Or you can head to "Common Intersections" if you have traffic problems and are looking for a new intersection.


Got a minute?
Please help me improve this guide, by answering this short survey.[forms.gle]
There are only a few question and it's 100% anonymous. Thanks!


1. Basic concepts
Road Hierarchy
You wouldn't put a house next to a highway, because that doesn't make sense, right? If you understand that, then you already know the basics of road hierarchy.

Roads have different functions and capacities. We usually split roads into 4 different 'types':

  • Freeway - Highest speed, no intersections.
  • Arterial - High speed, few intersections.
  • Collector - Medium speed, a lot of intersections.
  • Local - Low speed, direct access to buildings.

When you're designing your town, you should avoid connecting roads that aren't in that order. E.g., you shouldn't connect a collector road to a freeway, nor should you connect a local road to an arterial road.


Tip: Buildings should be along local and collector roads. If you place buildings along arterial roads, then cars will slow the road down when they're entering the building.

Space out your intersections
Your freeway and arterial roads needs high speeds, otherwise they're gonna clog up. But each intersection slows the traffic down at red lights, so you should try to space your intersections out like so:
  • Freeway - Minimum 500 meters between intersections
  • Arterial - Minimum 250 meters between intersections
  • Collector - Minimum 100 meters between intersections

The more space between each intersection, the better. If your roads are clogging up, try to spread out your intersections more.

Example of how this can be done in-game

Red - Freeway‎ ‎ ‎ ‎ ‎ Orange - Arterial ‎ ‎ ‎ ‎ Yellow - Collector ‎ ‎ ‎ ‎ Green - Local
Traffic flow 101
Traffic flow is actually quite simple. It’s easily explained by maths:

Flow = Speed * Vehicle Density

So, that basically means you can change 2 things to improve traffic flow. Either make the traffic go faster, or making the vehicle density higher by making more lanes.

That is the simplified version. It's a really complicated topic, so you can read more about it here.[en.wikipedia.org]

You have 3 options to improve traffic flow:
1) More lanes
2) Higher speeds
3) Fewer cars

Each of these options are good in different situations. Cars tend to slow each other down, if they want to turn or if there's a red light. Adding a turning lane can prevent turning cars from slowing down other traffic.

You'll often experience that not enough cars are crossing every time it turns green. To improve traffic flow in that case, you should add more lanes, so more cars can cross the intersections when it turns green. You could also remove the intersection entirely.

Tip: The easiest solution to traffic, is always to make good public transit. This is part of option 3, to have fewer cars. Give your Cims a good alternative to driving and they will use it.
The Rules of the Highway
Highways are different, as they're the backbone of your road infrastructure. If they get clogged up, then your whole city suffers. To prevent that, here are some rules you need to follow:

Lane mathematics
Ensure that the number of lanes on a road is the same as the total number of destinations there is, when the highway splits up. You can see that explained to the right:

There are some exceptions to this rule. For example, if you have a highway that splits into two different 2 lane highways, then 3 ‘entry’ lanes is often fine. But if you’re unsure, then always follow the lane mathematics.


Acceleration and braking lanes
If cars wanna merge from an ‘on-ramp’ onto the highway, then the car has to be going at the same speed. Otherwise cars won’t be able to go onto the highway, as they don’t have enough time to accelerate after merging. Look at the gif to the right to see that happening.

You have to make “acceleration” lanes from your interchanges, so cars can get up to highway speeds before merging with the highway.

You also need to make “brake” lanes, when you have an off-ramp from your highway. Otherwise cars will just brake on the highway instead of the ramp, slowing down all traffic behind it.



Design intersections wisely
There are 2 main highway interchanges: Diamond interchange and partial cloverleaf. This is what you’ll most often find in real life, and I advise you to use these mainly. But you need to choose carefully which interchange you’ll use, as all interchanges handle traffic differently.

(Left: Diamond interchange. Right: Partial Cloverleaf)
‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎







How to choose which interchange to use
Traffic jams almost always occur, when a lot of cars have to turn left from any lane. If there aren't a lot of cars turning left, then a diamond interchange is perfect.

You can predict this pretty easily: Where do you think the cars will come from, and where will they go? If you're expecting a lot of cars to turn left, then make a partial cloverleaf. Otherwise make a diamond interchange. A few cars turning left is not a problem, so only prevent left turns if it'll otherwise cause a traffic jam.

You NEED to make the right partial cloverleaf variant, otherwise it won't improve traffic at all. See "Partial Cloverleaf (+Variants)", under section 4. There's a detailed tutorial there.
‎‎‎‎
2. In-depth concepts
Where to zone residential, commercial & industrial
There is no right or wrong way to make a city. How you design your city is all up to you. However, each zone has different needs and difficulties, which you have to consider when you're building your city.

Residential

Things to consider
  • Noise levels - People don't like living near noisy areas like highways, airports, etc.
  • Pollution - People don't like living near spicy air as well.
  • Walking distance: Basic amenities such as elementary schools, shops, parks, etc. should be within walking distance of houses. Otherwise, they'll drive everywhere, which will cause traffic mayhem.
  • Traffic flow: You should avoid placing residential areas on bigger roads, if there is a lot of traffic. It's noisy and a traffic planner's nightmare, because it will slow down traffic on the road significantly.

Tip: Remember the road hierarchy, when you're building your residential areas. Try to avoid placing homes along arterial roads, and try to limit the amount of homes on collector roads. If you don't understand what that means, see the Road Hierarchy section.

Commercial

Things to consider
  • Needs consumers: Place in high traffic areas to attract more customers.
  • Proximity to Residential Areas: Ensure they are close enough for easy access by citizens.
  • Make a shopping area: Most cities have their shopping areas in the city centre. Businesses thrive next to train stations, bigger bus stops, etc.
  • Can cause a lot of traffic: A lot of people want to visit shops, so be prepared for that extra car traffic if people aren't walking.
  • You don't need it on every corner: A lot of guides advise you to put commercial areas on every corner and on bigger streets. That's not necessary.

Industry


  • Check the wind direction: Industries pollute, and it will be carried by the wind. Look at the wind map before you place industrial areas; otherwise, you might pollute some residential areas.
  • Redirect the traffic away from the city: A lot of trucks will come to your industrial areas. Make sure those trucks have a way out without going through the city center.
  • Remember public transport: A lot of people work at the factories, and they need to get there somehow. If there isn't a bus, then they will take the car.
  • Keep it semi-close to the city: People still need to get there. The further the area is, the more traffic is generated. But keep it far enough away, where it doesn't pollute the city.

Offices

  • Discourage car usage: Upwards of 600 people work in a single office building. Imagine how much space it would take, if everyone drove there. Seriously, you need public transport in these areas. You don't stand a chance, if you want to please the car demand.
  • Limit traffic throughput: A lot of people will walk to the offices. That will also cause quite a few problems at nearby intersections. But it's important to focus on the pedestrians, not car traffic
  • Office zones should be near the city center: Since the city center is usually the place where public transport meets, try to keep the offices near there. Seriously, discourage car use.


Okay, But where do I zone things?
The best way to learn is to look at how it's done in real life.

Let's look at how Banbury, UK, has zoned its city.

Imagery ©2024 Airbus, Map data ©2024 Google

As you can see, Banbury has a clear city center, near its train station. This area is filled with commercial zoning and medium-density residential zone, while the outskirts of the city have lower density residential zoning.

And here is the map of the roads in Banbury:

Imagery ©2024 Airbus, Map data ©2024 Google

Remember: Orange - 'Arterial' roads (Main roads). Yellow - 'Connector' roads. Green - 'Local' roads.

Notice how the main roads avoid going right through the center, where the commercial zone is. It goes right around it. If you were to make a main road right through a commercial area, then it would be heavily congested, as the speed would fall drastically. By having two main roads around the city center, you avoid having one traffic jam bring the entire city to a standstill, as cars can just go to the other main road.

Step-by-step guide







Understanding how Cims choose their route
This is one of the major differences between CS1 and CS2. In the new game, your cims will choose their route based on several factors, not just the total distance to their destination.

These factors are:
  • Time - Your cims usually prefer the quickest route. For example, they might choose a longer highway over a shorter, slower road.
  • Comfort - Routes are planned to avoid unnecessary turns and ensure smooth travel, including finding suitable parking or public transport stops.
  • Money - Travel and parking costs are weighed. Delivery vehicles consider fuel usage and resource transport costs, favoring local deliveries for cost-efficiency.
  • Behaviour - Different cims have varying risk tolerances in traffic. Emergency vehicles have more flexible behavior models, allowing them to make riskier decisions during emergencies.

Each of these factors has it's own 'cost'. When they compare the different routes, they'll choose the route with the lowest overall 'cost'.

Each traveler has their own preferences:
  • Teens - Prioritize cost, seeking cheap travel and parking options.
  • Adults - Focus on time, preferring the quickest routes.
  • Seniors - Value comfort, choosing routes with fewer comfort costs.

How to use this knowledge in-game
This knowledge is extremely useful in-game when you want to fix traffic jams. If your main road is totally blocked up, consider building a second road elsewhere or improving public transport. A lot of cims will choose to take this new route instead because it's faster.

Or if you have a bus line that is barely used, consider reducing the ticket price. More people will choose to take the bus now because it's cheaper. You can also make dedicated bus lanes so buses don't have to wait in traffic, making the journey way faster.

If you have a lot of car traffic coming into the downtown area, consider raising the parking fee. A lot of cims will choose to go by public transport instead, saving you from the traffic chaos where there is the least amount of space.

You can read more about this here[www.paradoxinteractive.com].
Parking spaces
Parking is a cheeky way to reduce traffic congestion. Because if there's nowhere to park at your destination, then there's no reason to drive there. Your sims will take public transport or walk instead.

This is what a lot of bigger cities do. They reduce the number of parking spaces in the inner parts of the city, so you have to park on the outskirts.

Spread out your parking spaces
You might think, that you want to place a lot of parking spaces in one place, for one reason or another. You should avoid doing that. Each car that parks at the parking space, needs to get there. This will cause a lot of traffic jams, if you place parking garages next to eachother, as several hundred cars will go to and from there.

You should try to spread out your parking spaces, as much as possible. Don't place parking spaces in busy areas, as that will bring more traffic into those areas. Try to spread them across the city and make sure that your roads can handle that extra traffic.


Park outside the city and take public transport into it.
As mentioned, real cities often try to limit parking spaces in the downtown area, so people have to park outside and take public transport.A good example of this is Amsterdam and the suburbs surrounding it. Let's take a look in the train station at the medium-sized city of Nijkerk, The Netherlands.


Imagery ©2024 Airbus, Map data ©2024 Google

There's a lot of parking space surrounding this train station. This is really common at train stations in the suburbs all around the world. But there are fewer parking spaces at each train station, the closer you get to the capital.

This also works in Cities:Skylines
So, remember to put parking spaces near and/or around any rural train stations you have. On the right, you can see what I've done at one of my train stations.

Don't go overkill. You still need commercial areas around train stations because there's a lot of consumers there. So find a good balance between commercial areas and parking spaces.




'Just one more lane, bro!'
You most likely do not need another lane.

Traffic occurs due to a bottleneck somewhere. But the solution is not to increase the size of the bottle: it's to fix where the problem actually is. Otherwise, you'll have the same problem, just with a wider queue.



This is straightforward, right?
Well, sometimes it's not as obvious as in this example.



Normally, this mistake is made at highway exits. A lot of people will upgrade the entire highway instead of fixing the off-ramp that is actually the problem.
In this case, it's as simple as making right-turning traffic go around the roundabout instead of joining it. That fixed the whole problem, and there is no need to upgrade the rest of the highway.

Just keep that in mind when you fix traffic issues. Upgrading existing roads with an extra lane will probably not fix traffic jams, as it's usually the intersections that are the problem.

Induced demand
Another thing you have to keep in mind is that your cims will often choose the fastest way to their destination. If there's a traffic jam, they might opt out and choose public transport or walking instead.

But if we fix all traffic issues, then suddenly it's faster to take a car than to walk or go by public transport. And because it's now faster, more cims will choose to drive. Thereby making your traffic issues worse rather than better.

So just keep that in mind. The easiest solution to traffic, is giving good alternatives to car traffic.




Cars and pedestrians don't mix well
It's often pedestrians who are causing traffic problems. If a large number of pedestrians are crossing a street, then cars have to wait a long time before they can continue.

Usually, it's not a problem on smaller roads. But a large number of cars and a large number of pedestrians, often causes serious traffic problems.

But just remember: Pedestrians are the solution, not the problem. Each pedestrian means one car less on the road. It's easy to handle large amount of pedestrians, but it's hard to handle large numbers of cars. So the solution to a lot of traffic problems is making it easier to walk and take public transport, rather than focus on the car traffic.

Tip: You can configure your intersections to have "Exclusive Pedestrian Phases", with the mod 'Traffic Light Enhancements'. This will give pedestrians the right of way before the cars, which can solve traffic problems in some cases. See more under the "Must-Have mods" section.

How do I solve traffic problems caused by pedestrians?
The best way to solve these problems, is to avoid intersections where there are a large number of pedestrians and cars. You have to consider: Where are the hotspots with a lot of pedestrians? This could be train stations, bus stops, high-density zones, etc.

Once you have found those areas, consider how you can reduce or avoid car traffic in that area. This could be making ring roads around the pedestrian hotspots, so cars are driving away from the hotspots instead of driving through them.


Lets take a look at Copenhagen, Denmark
On the left, you see the pedestrian 'hotspots' and connections by Metro and the S-Train.
On the right, you can see where the car traffic is. Orange is the 'arterial' roads, yellow is 'connector' roads.

As you can see, the pedestrian "hot spots" barely cross any major road. This is due to the Metro stations, which are placed at all ends of the pedestrian hotspot area. The Metro is the primary way pedestrians enter and leave the area, so pedestrians don't have to cross larger roads to get to and from these 'hotspots'.


Example of how this can be implemented in Cities: Skylines 2
As you can see, the pedestrian zone (blue zone) is largely separated from the car traffic (yellow and orange zone). This station is used by roughly 80.000 people monthly without causing any traffic problems.

Tip: You don't need to do this most of the time, especially in rural towns with a low population. The main takeaway from this, should be that you shouldn't place pedestrian 'hot spots', such as train stations, right next to very busy roads.

Alternate ways to solve traffic problems caused by pedestrians
If your pedestrians absolutely have to cross a major road, the most basic way is to make overpasses.

This guide will not go in depth on how to make overpasses, as the main point is that you should avoid situations where you even need them. But here is a useful guide from the user 'sens0r':

https://steamproxy.net/sharedfiles/filedetails/?id=3068023412
The "Stair and Path Assets Pack" is also a useful mod. Link[mods.paradoxplaza.com]

‎ ‎ ‎
3. How to fix most traffic problems
Queue to turn left
TBA
A lot of traffic jams occur, simply because not enough cars are crossing the intersection every time it turns green.

Luckily, the solution is very easy: Simply make more turning lanes. You don't need to upgrade the entire road; you only need to make another turning lane at the intersection itself.
Intersections too close to eachother
Cars wait in line at a red light. But if there's not enough space for a line, then you risk not having enough cars get over the intersection every time it turns green.

So simply space out your intersections more, so there's more space for cars waiting in line at the intersections.
Too sharp turn at exit ramp
A common mistake that causes a lot of traffic jams is making sharp turns.

Cars slow down when there's a sharp turn, which is really bad for traffic flow. Especially at highways and arterial roads.

So simply smooth out your roads, if you encounter traffic jams at turns. You should also avoid making sharp turns on high-speed roads in general.
Right-turning cars stuck behind left-turning cars

If a few cars are turning left, then they risk blocking the entire line behind them. By making a separate turning lane further down, you will be able to alleviate the traffic jam in a lot of cases.

If this doesn't work for you, try to make a separate right-turn lane at the intersection.
4. Common Intersections
Highway to Highway interchange
A highway to highway interchange, are also known as "System Interchange". Interchanges that connect a highway to a street or road, is called a "Service interchange". You will find Service Interchanges in the next section.

'Four-legged' interchanges'
These interchange are normally used, when you need to connect 2 highways that are crossing.


Cloverleaf Interchange
Traffic Flow: 2/5
Space efficiency: 4/5
Ease of Building: 5/5


Pros: The cloverleaf interchange is available in the base game under "Intersections". There is no need to build it yourself.

Cons: The cloverleaf interchange can lead to weaving problems where drivers need to cross paths, which quickly turns into a traffic jam affecting several directions.

How to build: Tutorial*
IRL example: Map[www.openstreetmap.org]
*You can also find it under "intersections" in the base game.

Cloverstack
Traffic Flow: 4/5
Space efficiency: 2/5
Ease of Building: 4/5 - You can modify the stock Cloverleaf, which is under "Intersections"


Pros: Basically an improved cloverleaf, without the weaving problem. Handles a large amount of traffic pretty well.

Cons: It's one of the biggest interchanges there are. If space is a problem, this isn't for you.

How to build:Tutorial
IRL example:Map[www.openstreetmap.org]

Tip: You don't need to build both off-ramps. If only one side has traffic problems, then you can just make the "flyover" ramp on that side.

Turbine Interchange
Traffic Flow: 5/5
Space efficiency: 2/5
Ease of Building: 3/5


Pros: Turbine interchanges offer smooth traffic flow with minimal weaving. It's really good at handling a large volume of traffic. Also looks cool.

Cons: They're extremely big. Not suitable for urban areas.

How to build: Tutorial
IRL example: Map[www.openstreetmap.org]

Inside Turning Left interchange
Traffic Flow: 4/5
Space efficiency: 5/5
Ease of Building: 2/5


Pros: Inside left turning intersections simplify left turns, with all left turning lanes going in the middle. This is extremely space efficient, and has a high traffic flow.

Cons: Upgrading this interchange is very impractical. If you experience traffic jams with this interchange, it's better to make another interchange completely.

How to build: No tutorial exists yet.
IRL example: Hasn't been built yet

Windmill Interchange
Traffic Flow: 2/5
Space efficiency: 2/5
Ease of Building: 4/5


Pros: Windmill interchanges are easier to build than a turbine interchange.

Cons: Cars slow down a lot when taking a left turn. I would highly recommend just making a turbine interchange instead, as it's much more efficient and takes an equal amount of space.

How to build: Tutorial
IRL example: Map*[www.openstreetmap.org]
It's only a partial windmill interchange!

Stack Interchange
Traffic Flow: 5/5
Space efficiency: 3/5
Ease of Building: 5/5 - Stock interchange


Pros: Really efficient at moving a lot traffic quickly. Traffic barely slows down when turning, due to its very wide turning lanes. Perfect for handling a high traffic volume.

Cons: It takes up a lot of space, due to the high speeds it has. Not suitable for urban areas.

How to build: Tutorial*
IRL example: Map[www.openstreetmap.org]
*You can also find it under "intersections" in the base game.

Braided interchange
Traffic Flow: 4/5
Space efficiency: 4/5
Ease of Building: 1/5 - I wouldn't wish upon my worst enemy to recreate this

Pros: Braided interchanges eliminate weaving by separating crossing traffic streams, enhancing efficiency.

Cons: They are complex to design and build, requiring careful planning and a lot of trial and error.

How to build: No tutorial exists yet.
IRL example: Map[www.openstreetmap.org]

Three-level roundabout
Traffic Flow: 1/5
Space efficiency: 3/5
Ease of Building: 5/5

Pros: The roundabout interchange is really good for areas, where you're limited for space and you have a low traffic volume that wants to turn to the adjacent highway.

Cons: Extremely inefficient at handling traffic that wants to turn. Will easily cause traffic jams.

How to build: Tutorial*
IRL example: Map[www.openstreetmap.org]
*You can also find it under "intersections" in the base game.

Pinavia Interchange
TBA




'Three-legged' interchanges'
Normally used when you need to merge a highway into another.


Tip: The following interchanges can also be used as a highway exit, onto an arterial road. They are really good at that, because there's no intersection.

Trumpet interchange
Traffic Flow: 3/5
Space efficiency: 5/5
Ease of Building: 5/5


Pros: Trumpet interchanges are effective at connecting a freeway with an arterial road and smaller highways.

Cons: It's not good at handling large traffic volumes. If there's a lot of traffic, use the Y-interchange instead.

How to build: Tutorial*
IRL example: Map[www.openstreetmap.org]
*You can also find it under "intersections" in the base game.

T-interchange
Traffic Flow: 4/5
Space efficiency: 3/5
Ease of Building: 5/5


Pros: T-interchanges are simple and cost-effective to build, suitable for low-traffic areas where three roads meet.

Cons: They are less efficient for high traffic volumes, often leading to congestion and requiring drivers to make sharp turns, which can be hazardous.

How to build: Tutorial*
IRL example: Map[www.openstreetmap.org]
*You can also find it under "intersections" in the base game.
Highway to Arterial intersections
There are basically only 2 types of Highway to Arterial intersections: Diamond and Partial Cloverleaf. If you choose the incorrect one, then you may experience traffic jams. That is all explained under "Partial Cloverleaf (+variants)".
‎ ‎ ‎ Partial Cloverleaf (+variants)
Traffic Flow: 5/5
Space Efficiency: 4/5
Ease of Building: 3/5

Pros: The partial cloverleaf is a great compromise between space and functionality. It can handle large traffic volumes, if it's built correctly.

Cons: It's better at handling large traffic volumes than a diamond interchange, but it's not any better, if it's built incorrectly. It's also more difficult to build than a diamond interchange.





Why would I build a partial cloverleaf instead of a diamond interchange?
Partial cloverleaf interchanges are more efficient at handling large traffic volumes, than a classic diamond interchange. This is because you can eliminate left turns, which is normally what causes delays.

However, a partial cloverleaf will not perform better than a diamond interchange, if they're not properly built.

How to make the correct partial cloverleaf

The goal is to prevent a lot of traffic from turning left. A few cars turning left is not a problem, so only prevent left turns if it'll otherwise cause a traffic jam.

You pick what variant you use, by assuming where the traffic will primarily come from and where they'll go. Remember, if a car goes somewhere, then it's likely that it will come the same way back.

When you know where the traffic flow will be, take a look at all variants and see what fits your case the best. Look at bit further down on the page, to see all variants.




Did you understand that? Try to take this little quiz:
There's a lot of traffic coming via the red and green arrow. The cars are driving on the right side.
What variant would be best in this situation?


Answer:
B3 or B4

Explaination:
The goal is to prevent left turns, if there's a lot of traffic. A lot of traffic is coming from the left side and it wants to go up and down when joining the main road. All "A" variants don't work in this situation, as the green cars only have 1 lane that goes both north and south. Therefore someone has to turn left. B2 doesn't work either, for that same reason. B3 and B4 is perfect, as no major route has to turn left at any point.


Partial Cloverleaf variants
A: The 2 ramps meet the freeway ahead of the crossing with the arterial road (main road)
B: The 2 ramps meet the freeway beyond the crossing with the arterial road (main road)
The number: How many quadrants of the interchange has a ramp.

‎ ‎ ‎ Diamond Interchange (+variants)
Diamond interchange
Traffic Flow: 3/5
Space Efficiency: 4/5
Ease of Building: 5/5

Pros: Diamond interchanges are straightforward to build, and they provide a direct connection between highways and arterial roads without using a lot of space.

Cons: They can easily be overrun. Diamond interchanges are really only for low-medium traffic volumes, as they don't handle high traffic volumes very well.

How to build: Tutorial
IRL example: Map[www.openstreetmap.org]


Diverging Diamond Interchange
Traffic Flow: 4/5
Space Efficiency: 4/5
Ease of Building: 3/5

Pros: Diverging diamond interchanges improve traffic flow by allowing direct left turns without crossing opposing traffic, reducing congestion. They also look really cool.

Cons: They're more difficult to build than a diamond intersection.

How to build: Tutorial
IRL example: Map[www.openstreetmap.org]


Contraflow left turn
Traffic Flow: 4.5/5
Space Efficiency: 3/5
Ease of Building: 2/5

Pros: Contraflow left turn interchanges improve traffic flow by eliminating left-turn conflicts, allowing left turns to be made from a temporary contraflow lane. It works surprisingly well.

Cons: It requires a lot of lanes to function properly. That makes it extremely wide, but it's still a good choice for urban areas.

How to build: No tutorial for this configuration exists yet!
IRL example: Map[www.openstreetmap.org]



Three-level diamond (Volleyball) Interchange
Traffic Flow: 4/5
Space Efficiency: 2/5
Ease of Building: 2/5

Pros: Three-level diamond interchanges are really good, if you have an arterial road with a lot of traffic, that isn't going to the highway.

Cons: This interchange is a pedestrians worst nightmare. Make sure you have other overpasses for pedestrians.

How to build: No tutorial exists yet!
IRL example: Map[www.openstreetmap.org]


Split Diamond
Traffic Flow: 3/5
Space Efficiency: 2/5
Ease of Building:4/5

Pros: Split diamond interchanges distribute traffic across multiple intersections, reducing congestion at a single point. They can be more effective than a diamond interchange, as the turning-lanes are way bigger.

Cons: It requires way more land, as the roads have to merge again. That merging requires about 100 meters of land, which can't really be used for much due to the roads curvature.

How to build: None exists yet, but they're really simple to build.
IRL example: Couldn't find one irl


Michigan urban diamond
Traffic Flow: 4/5
Space Efficiency: 5/5
Ease of Building: 4/5

Pros: Michigan urban diamond interchanges prohibit left turns at the main intersection, so left turning traffic has to do a U-turn further down. This improves traffic flow surprisingly well.

Cons: If one of the intersections gets clogged up, then everything will come to a standstill.

How to build: No tutorial exists yet!
IRL example: Link[www.openstreetmap.org]


Dumbbell interchange
Traffic Flow: 2/5
Space Efficiency: 4/5
Ease of Building: 4/5

Pros: Dumbbell interchanges are basically diamond interchanges without signalized intersections. This can reduce delays a lot.

Cons: The roundabouts can easily become congested, and that can cause a lot of traffic jams.

How to build: Tutorial
IRL example: Map[www.openstreetmap.org]


Roundabout Interchange
Traffic Flow: 4/5*
Space Efficiency: 4/5
Ease of Building: 5/5

* Traffic is vastly improved, if you add bypass lanes.

Pros: The Roundabout Interchange is a good rural and urban interchange. Doesn't take up a lot of space, handles traffic pretty well and is easy to build.

Cons: Cims aren't very good at handling custom roundabouts. You'll have to adjust it a lot, until the AI acts the way that you want it to.

How to build: Tutorial
IRL example: Map[www.openstreetmap.org]

Note: Thank you to the person who recommend this interchange in the survey. If you have a moment, please fill the survery out here[forms.gle]. It really helps me out!
5. Useful tips & Ressources
Recommended mods
Traffic Lights Enhancements
Link to mod [mods.paradoxplaza.com]
Creator: C2VMTLE


With this mod, you'll be able to configure traffic lights so they light up in different ways. If you need protected left turns or only allow one side of an intersection to be green at a time, then this is the mod for you!

Here's a short summary of what the mod can do to intersections:
  • Vanilla
    Operates like the base game

  • Split Phasing
    Only one road has a green light at a time.

  • Advanced Split Phasing
    Split phasing with additional protected turns for other roads

  • Protected Left or Right Turns
    Center lanes perform a protected left or right turn first
There's also a lot of other options, such as "Allow Turning on Red", "Give Way to Oncoming Vehicles", "Exclusive Pedestrian Phase" etc.



Tip: If you want an in-depth guide and illustrations, go to the developers own guide[github.com]

This short summary was written by the developers of the mod. Full credits to them, and thank you for making a fantastic mod!


Traffic by krzychu124
Link to mod [mods.paradoxplaza.com]
Creator: krzychu124

This is a tool that allows for changing lane connections at intersections to any that suits your use case.

On the bottom right, there is a useful case where this mod can help. If a car comes from the left and wants to go to the top road, then it will block most traffic on the main road while waiting for free clearance.

By simply selecting the nodes and making left turns illegal, traffic will flow much smoother.

I personally use this mod all the time. It's a lifesaver, if you have traffic problems. A massive thanks to krzychy124 for constantly making updates.

Road Builder by T.D.W
(Sorry for the flickering gif!)
Link to mod [mods.paradoxplaza.com]

Make your own custom roads with Road Builder! Change any part of the road, to fit exactly what you need.

Wanna make a divider between the normal road and a turning lane? Road builder simplifies this a lot. Simply drag and drop the median on the road builder menu, and voila.

Absolutely amazing mod. The original game should've had something similar, it's extremely useful. The mod is still in beta version, so expect a few bugs here and there.

Thank you T.D.W! Good job.
Finale & Credits
That's all, folks!

I hope you learned something new and found this guide useful. This guide is still in its early phases, so I would appreciate some feedback in the comments. Especially if something is unclear, some media don't show, etc. If you just have a question, leave a comment, and I'll see if I can help.

If you have a traffic jam scenario that could be added under "How to fix most traffic problems", feel free to add me, and let's have a chat.


Got a minute?
Please help me improve this guide, by answering this short survey.[forms.gle]
It's 100% anonymous and should only take a few minutes. Thanks!

19 Comments
Topazzu 18 Jan @ 4:47am 
Really helpful. Thanks from a beginner.
Still, cars are trying their best turning around, crossing yellow lines, occupying bus lanes etc.
Just the same version of reality.:steamfacepalm:
Beshman 1 Jan @ 8:23am 
The parking AI is super extreme. If you have 1 parking spot open, until it is filled, all cars will attempt to park there, and if not, will then try a new spot. Even with a park and ride situation. They'll go back to the park and ride after being in the city, drive to a potential spot, when its filled, will then drive back again to the park and ride. Also the roundabout AI doesn't work correctly. Traffic is the biggest issue in this game now, but unlike CS1, where adding public transport (which i put as free) and adding paths, works, it doesn't seem to work in CS2.

Good guide though (sorry for rant) xD
hr kartoffel  [author] 28 Dec, 2024 @ 12:36pm 
Huh, I wonder how that ended up there. Thanks for pointing it out!
unforgiven3091 27 Dec, 2024 @ 8:07am 
I think you accidentally pasted something into the Dumbbell interchange section "Space Efficiency: 4/5javascript:BBCode_MakeListFromSelection();"
daniil_cool_off 21 Dec, 2024 @ 3:46pm 
Thank you! It is great!
Mɾ. Hσʅʅყɯσσԃ 6 Oct, 2024 @ 6:15am 
Solid
Dellonia 5 Oct, 2024 @ 2:23am 
Great guide, makes it really easy to understand how to organise a city.
I was wondering, how would you treat office buildings? buffer with industrial? mixed in the center of a residential or commercial area?
hr kartoffel  [author] 11 Sep, 2024 @ 8:51am 
People do that in real life too. You just don't notice it, because the traffic planners did account for that when they made the road. They made barriers, separated turning lanes or road markings making lane changes illegal at certain points. You have to plan for that as well, which is quite easy.

Remember, just like in real life, drivers take the quickest route available. And if that route is cutting across traffic, then a lot of drivers will do that.
dumb magpie. 11 Sep, 2024 @ 7:34am 
idk, i like the guide but i feel like almost all of it is mute because people will just change lanes in the middle of the road anyways. That seems to be the main cause of issues imo
hr kartoffel  [author] 8 Sep, 2024 @ 6:07am 
I wouldn't recommend that, because it will disrupt traffic flow even if its only a few houses. Also, there's a lot of noise near arterial roads and residents generally don't like that :)