Fixing Traffic Jams

Overview

For those of you frustrated with traffic jams, this guide presents a step-by-step approach to managing traffic flow problems. It highlights gems of knowledge buried in other guides, saving you time and effort.Feel free to dive into whatever section piques your fancy. If you feel lost, it may be worthwhile to read the sections in order.This guide is targetted primarily at PC players due to the mention of mods. However, it can serve as a good reference for Playstation, Xbox, and Nintendo Switch players as well.This guide is mostly done. I do minor edit changes as time permits.If you found this guide helpful, give it a thumbs up, make it a favorite, or share it with others.

Prerequisites

I assume you are reading this because you want to understand (and solve) the mystery of traffic jams and traffic flow headaches.

In order to get the most “bang for your buck” from this guide, I assume you:

• have played the vanilla version of this game without mods for a few hours;
• downloaded and experimented with a few mods;
• built multiple cities with varying degrees of success (or not); AND
• ran into traffic jams that make you wonder if the game is broken (and led you to this guide)

The above points are a common “frame of reference” regarding what the game does and can do (via mods). Without these experiences, it will be difficult to understand why the rest of this guide matters. This guide assumes you learn by doing.

I assume you want to play the game “legitimately”. That is, you do not use the mod “Unlimited Money” (but other mods are fine). This mod is tailored for those who want to focus on designing cities rather than planning/managing their growth. Nothing wrong with this; it is just a different playstyle/focus. You, on the other hand, are trying to plan/manage your city over time. This is much more challenging (and frustrating).

I have done my best to simplify things—not that understanding and managing traffic flow problems is a simple matter when you dive into the details. The sections are written to cover breadth (that is, a mile-wide but an inch-deep). Within each section, there may be headings that go deep, delving into a specific sub-topic. You can ignore diving deeper if you are not interested. You can even read the sections out-of-order if you wish.

Is Traffic Simulation Broken?

If you are like me, you do not plan your city’s design nor its growth. You add more roads, more zones, and more service buildings as it suits you. And as your cims demand them (sometimes not even then). Growth is haphazard. Maybe you do some small urban planning here and there. For the most part, you do what piques your fancy in the moment.

Your goal is to grow your city’s population to the point where your city’s treasury is collecting enough taxes to stay in the green. And you are only doing this so you can:

• buy the next service buildings;
• have enough in the bank to design that cool road interchange you saw on some website; OR
• <insert whatever cool thing you want to build for your city>

There is no regard for traffic flow. One day, you realize there is a long pile up of cars and trucks along one or more roads. You do your best to untangle the jam (without any real idea how to do this except to widen the road). Nothing seems to work or if it does, it is only temporary. You start wondering if the traffic simulation is broken.

For the longest time, I thought the traffic simulation was broken. Then I decided to educate myself on real-life traffic planning and traffic management. This took time and effort outside of the game.

Turns out the game’s traffic simulation is fairly accurate (not perfect by any means). So no, the traffic simulation is NOT broken.

It took me a long time to see this perspective. Traffic simulation only looks broken when you do not know what contributes to traffic flow problems.

When I used to hold onto the idea that the traffic simulation MUST be broken, what I was really doing was forcing my ideas onto the reality of the game mechanics. Believing something to be a certain way does not make it so.

After tossing my beliefs away and embracing the game mechanics as they are, things started to flow more smoothly. Accepting the traffic simulation as-is is not the same as liking it. I still think cims are stupid for erratic lane changes on highways that lead to nasty pile-ups. You know what I mean.
<Shakes angry fist at cims who do not know how to drive> But this will be addressed in a later section.

It is easier to work with the system than fight the system.

If you want to use mods that modify (or break) the traffic simulation, go right ahead. Just be prepared that when things go wrong, you will have to figure out if this makes sense or not. Perhaps create a guide to help you understand things.

Why Do Traffic Jams Happen?

The first step to solving a problem is to understand it. Knowing is half the battle.

As you may or may not be aware, the developer, Colossal Order, worked very hard to build a realistic traffic simulator in-game. You can read about this in the Development section of Wikipedia, Cities: Skylines[en.wikipedia.org]. Your frustrations reflect what would happen if your road layout were built in real-life. Now, back to the game.

Traffic jams are caused by one thing, cims. The more cims you have in your city, the more vehicles are on the road, and the higher the chance a traffic jam will occur. As an aside, when you dive into the details of traffic flow theory, the number of variables makes things complicated. We do not need to know the game’s pathfinding algorithm; just know that more cims equals more traffic jams.

So one way to 100% eliminate traffic jams is to have no cims in the city. 🤦(← it is a /facepalm; [:steamfacepalm:] no work!) How much fun is staring at this map in-game?

Makes for a very un-fun experience. And you are here to have fun.

Traffic jams appear when the amount of traffic through an area exceeds the carrying-capacity of the road layout in that area. If a road layout can only handle, say, 20 cars/trucks per in-game day and it gets 40 cars/trucks, well then, a traffic jam occurs. In the screenshot below, you can tell where a traffic jam will start. The circled 4-way intersection is a hotspot for cims coming and going.

The road layout is not “bad”, per say; it is just that current demand exceeds its capacity to provide. The fact that we cannot “see” what maximum carrying-capacity a particular road layout can handle is what leads to our frustrations (and thoughts that the game’s traffic simulation is broken).

Alright, I stated the obvious. Some of you may be wondering “so what?”, “how is this information going to help?”. This is the subject of the next section.

There was a time when I tried to predict where traffic jams would occur. I would upgrade 2-lane roads to 4-lane roads or even 6-lane roads. Sometimes I guessed correctly but most times not.

When you start building/growing your city, the first location for a traffic jam is likely the highway interchange that brings your first cims and goods into your city. Obvious, I know. After this site, the next traffic jam location is anyone’s guess.

Traffic jams are an emergent behaviour over time. It happens in real-life cities and in your game cities. It is part of the growing pains of any healthy city.

For the sake of sanity, I recommend not worrying about where they will occur. 🙂 Just react to them when they do occur.

Ummm, no. As frustrating as they are, traffic jams are a good thing. Before you flame me, let me explain.

Traffic jams indicate a demand for goods/services in a specific area. This is good because it indicates growth in that area. And you want growth in order to collect more tax money for your city’s treasury.

Learning to manage this growth is at the core of reducing traffic jams. That is, think of reducing traffic jams as another task in managing a growing city. I say “reduce” and not “eliminate”. You already know how to eliminate traffic jams. It is un-fun.

How to Deal with Traffic Jams?

Now that you understand WHY traffic jams occur (due to a combination of high demand and lack of capacity), we can focus on ways/approaches to reduce traffic flow problems. At the most basic theoretical level, reducing traffic jams is a simple matter of increasing carrying-capacity among problematic sections of your road infrastructure. Of course, achieving increased carrying-capacity is not straight-forward. There will be twists, turns, and dead-ends toward this goal; no pun intended.

Learning some theory behind traffic planning and traffic management greatly helps to understand the relevancy of the following concepts, tips, and techniques. Below are links to guides/websites that I found helpful in my journey to understand. They are in no particular reading order. Just read what you can, when you can.

• [link]
• [link]
• Types of Road Interchanges[en.wikipedia.org]
• Roundabout[en.wikipedia.org]
• Dictionary of Interchanges[www.roads.org.uk] Well illustrated website about various types of interchanges and WHY they matter.

Theory is important when you want to learn the art of untangling traffic jams. Theory gives us a common frame of reference to make sense of what appears to be a traffic mess.

It is an art because there is no straightforward recipe of what concept to apply when. The art comes from applying whatever concept you think works in a trial-and-error fashion to figure out how effective it is for a particular situation. This is what makes an artist in any profession an artist (I speak metaphorically).

As you may notice from reading the guides, Residential Zones form the hub between Industrial Zones and Commercial Zones. Without residents, you have no industry and no commerce. As the number of residents increases, they want more jobs and more places to shop. This increases demand for more imports to industry and more goods to commerce; hence more vehicles on the road. This is a perfect recipe for creating traffic jams.

From my experiences, I notice that traffic jams form in-and-around Industrial Zones first before spreading out to Commercial Zones. In-and-around Residential Zones are the last places to experience traffic jams. Depending on how you lay out your Residential, Industrial, and Commercial Zones, your experiences may vary.

When you cannot ignore a traffic jam, try the following steps. The order is important.

• Step 1: Stop what you are doing and let traffic settle down.
• Step 2: Review the list of tools at your disposal.
• Step 3: Pick just one tool.
• Step 4: Make small changes at the traffic jam location using that tool.
• Step 5: Wait-and-see.
• Step 6: Verify the results.
• Step 7: Undo changes (as best as you can) if things do not work out.

(Step 1) City growth and traffic interact with each other in unexpected and unpredictable ways. Allow your city the time to saturate zones. I usually give it a few in-game weeks, sometimes even a month. It is easier to fix a traffic jam when it stays in one place and is not moving around the city every in-game week or so.

(Step 2) Refer to section “Tools of the Trade”.

(Step 3) It is easier to focus on one thing at a time. Any traffic changes that result from the use of that one thing forms a pattern in your mind. If it is a useful pattern, it is easier to remember for the next time.

(Step 4) You want to get to a stable situation before moving onto an unstable one; this is the nature of progress. This is a lot easier taking baby steps.

(Step 5) Let the traffic simulation run for a few in-game weeks. Just watching may be tedious, but it is necessary. What you are doing is letting the traffic simulation settle down into a new “normal” because of your changes. No one ever said this would be exciting (unless you love traffic planning and/or management). But this is why “Cities: Skylines” gives you an Accelerate Time feature; use it. 🙂

(Step 6) Use the Traffic tool to see if traffic flow improved or not. If not, go to Step 7. If yes, you can stop here and go back to managing/growing your city.

(Step 7) Restore the old road layout either by re-building it again or re-loading a saved game. If you are re-building it, give the traffic simulation a few in-game weeks to reproduce the problem. Then go back to Step 3 and choose another tool. It is easier to deal with the same traffic jam rather than solve a different traffic problem each time you make an unsuccessful change.

The Mitigation Steps might appear simple and obvious. But when traffic jams interfere with you building/managing your city, it is easy to overlook the process.

Tools of the Trade

Tools are broken down into 4 sub-sections:

• Helpful Concepts
• In-Game Tools
• Types of Road Layouts
• Road Types

These are in no particular order of importance.

• HelpCon01: Ignore the problem.
• HelpCon02: Space out your intersections.
• HelpCon03: When in doubt, apply a simple (road) layout.
• HelpCon04: Bifurcate your traffic. That is, divide traffic into two branches. Or just say, fork-it!
• HelpCon05: Think about looping your traffic.
• HelpCon06: Identify the Origin and Destination of your traffic (as best as you can).
• HelpCon07: All road layouts have finite carrying-capacity.
• HelpCon08: When you re-zone or create/modify roads in your city, you are changing traffic flow patterns.
• HelpCon09: Smooth out intersections as-needed.
• HelpCon10: Destroy the current road layout and build a different road layout.

(HelpCon01: Ignore the problem.) Unlike real-life, some problems just go away on their own. I figure this is the default behaviour for most people. This will make sense in the “Applied” sections.

(HelpCon02: Space out your intersections.) The in-game warnings actually indicate a problem area. Ignore at your peril. If you have an intersection whose distance to the next intersection is 8 cells/tiles or less, expect to deal with traffic congestion there. Spacing out intersections at least 16 cells/tiles apart seems to alleviate traffic congestion, at least for a while.

(HelpCon03: When in doubt, apply a simple (road) layout.) Generally speaking, a simpler road layout does not make a traffic jam worse. And it is easier to solve a simple problem you have already seen rather than a complex one with which you have no prior experience.

(HelpCon04: Bifurcate your traffic.) A T-intersection (or Y-shaped junction/intersection) should be your first thought when faced with a traffic jam. It causes traffic to spread out by forcing some vehicles to flow right or to flow left. The carrying-capacity of the road layout increases because the load is shared among two branches of traffic instead of one.

(HelpCon05: Think about looping your traffic.) Roundabouts are an obvious choice. But a 6-lane road, say, that winds through and/or around your city and connects back to the highway does the same thing. It does not have to be round, it just has to loop. <insert screenshot>

(HelpCon06: Identify the Origin and Destination of your traffic.) This is explained in Steam guide “Traffic Planning Guide for Realistic Cities” by Dimethylmercury_. The Routes tab in the Traffic Routes tool helps, but you have to click on several road segments (and filter on different Transport Types) to figure out where the traffic is coming from or heading to. If you are lucky (or gain more traffic planning/management experience), sometimes you can eyeball where traffic is coming from or heading to. <insert screenshot>

(HelpCon07: All road layouts have finite carrying-capacity.) There is no such thing as an ultimate road layout that has infinite carrying-capacity. As your cim population increases, be prepared for traffic jams to re-appear on road layouts that resolved previous traffic jams. If you settled on a certain population size and reached it, your traffic problems will be stable, more or less.

(HelpCon08: When you re-zone or create/modify roads in your city, you are changing traffic flow patterns.) Expect any road/zone changes to move current traffic problems to different areas of your city.

(HelpCon09: Smooth out intersections as-needed.) How one road smoothly/abruptly intersects with another road greatly affects how much traffic flows through that intersection. Most times a simple T-intersection will do. For connecting to highways, a smooth, curving lead-in road or lead-out road will provide far greater flow.

(HelpCon10: Destroy the current road layout and build a different road layout.) This is a radical move; I consider it a concept of last resort. It completely changes the nature of the current traffic problem to a new one. This may or may not improve traffic flow. If you apply this concept, you definitely need to apply Mitigation Step 5 (wait-and-see approach).

These are in no particular order of importance.

• Traffic tool
  

• Routes tab inside the Traffic Routes tool
  

• City Treasury
  

• Accelerate Time feature
  

Why is the City Treasury a tool? It might seem odd but it is the only tool that allows you to test out various road layouts. It also buys you time while you study traffic flow problems (especially when the city has expenses greater than income). The more money in the City Treasury, the more time and the more road layouts you can use.

I cannot stress how important it is to use the Accelerate Time feature. It speeds up traffic flow so it settles into a new “normal” after you made changes. Depending on the speed of your CPU (and how many cores it has) and how large your cim population is, you may notice that Accelerate Time does not appear to work. As a general rule of thumb, the larger your city becomes, the less Accelerate Time can crunch the numbers faster than playing at normal speed. Computers have finite computing power, after all. Simulations expose the limits of one’s computer when you push the simulation as far as it can go.

Too many to list here but here are some common ones. These are in no particular order of importance. See Types of Road Interchanges[en.wikipedia.org] and Roundabout[en.wikipedia.org] for a fuller list.

• Cloverleaf interchange
  

• Roundabout
  

• Overpass (road A) and underpass (road B)
  

• T-intersection
  

• Embedded windmill interchange
  

Not sure if there is a better name for the “embedded windmill”. Discovered this idea on a Reddit post back in 2017. I found it so useful that I thought it deserved mentioning.

As provided in-game.

• 2-lane road
• 4-lane road
• 6-lane road
• 1-way road

They can be used to increase/decrease the carrying capacity of a section of road. The wider road types only work well if traffic spreads itself among the available lanes.

Mods and DLCs

I thought the discussion of mods and DLCs deserved their own section instead of being buried inside section “Tools of the Trade”.

These mods are not necessary to solve traffic jams. If you play the vanilla game without mods, you may have to get creative to solve traffic flow issues.

These mods make untangling traffic jams easier if you know how to use them effectively. I regularly use them to improve traffic flow in my maps.

• Automatic Bulldoze v2
  [link]
• Better Cemetery AI
  [link]
• Fine Road Anarchy 1.3.5
  [link]
• Fine Road Tool 1.3.7
  [link]
• Precision Engineering
  [link]
• Traffic Manager: President Edition [1.10.15-stable]
  [link]

Mods “Automatic Bulldoze v2” and “Better Cemetery AI” are not used to directly improve traffic flow. They automatically handle abandoned buildings and dead cims. When I work on traffic flow issues, I choose not to be distracted by abandoned buildings nor dead cims.

I use mod “Precision Engineering” a lot when I lay down roads that need to be aligned with pre-existing road infrastructure. This does not mean my road layouts are always grid-like. The mod is useful for laying out curved roads as well.

Mod “Traffic Manager: President Edition” is indispensable. It can re-organize traffic in a way the vanilla game cannot. Having said this, I use it as a scalpel. Only when I have exhausted all other methods do I resort to using this mod. When I used it as a chainsaw, I really screwed up traffic in my cities to the point where traffic flow was below 60%; this lead to negative income in my city treasury.

I do my best to play vanilla-style as much as I can. I do this NOT to be a purist nor to play as “legitimately” as I can. From the school of hard knocks, I learned that the game’s traffic simulation punishes you if you fight against it. “How?”, you ask.

When I did not know what caused traffic jams, I would mis-apply the mods above and make a minor traffic jam worse. Fixing the fix with the mods made a worse situation catastrophic. Eventually I ended up with permanent grid lock in my city. My city’s treasury was consistently losing money.

I was at a loss to understand why. I abandoned this “loser” map and started again on a different map, thinking “this time will be different”. And I ended up with the same situation, grid-lock, negative income, frustration, and quitting the map.

My thoughts of “this traffic simulation IS BROKEN” also bled into the mods with thoughts of “the MODS are useless/ineffective”. Took a while to realize the problem was me. I needed to understand what I did not understand.

These days, I use the mods as scalpels. They are used for fine, detailed work only where necessary. I do my best not to fight against nor mess with the traffic simulation. Bad things happen when you do not know what you are doing or what is happening underneath the hood. 🙂

When you have a traffic flow problem, try to exhaust vanilla-style play techniques first before resorting to these mods. Simple is best. The mods are more effective as scalpels than as chainsaws.

You do not need any DLC (that is, DownLoadable Content) in order to enjoy “Cities: Skylines”. However, if you want to improve traffic flow and/or make easy money, consider the following DLCs.

• Mass Transit DLC
  

• Snowfall DLC
  

• Parklife DLC
  

“Mass Transit DLC” provides ferries, blimps, cable cars, and monorails. It also provides hubs that integrate different modes of transport such as buses and ferries or buses and monorails. This can increase the carrying-capacity of your roads by providing alternate transport methods.

“Snowfall DLC” provides trams. It seems a bit of overkill just for this one new transport mode. However, if you are a completionist then you will want this DLC if you like/prefer trams in your city.

“Parklife DLC” allows you to charge a toll each time a cim visits one of your custom parks. See Steam guide “Making Better Money with Parklife DLC” by Haverstash on how to profit from this DLC.

Applied: How to Use?

This section deals with the question “All this theory is nice but how do I actually USE any of it in-game?!?” Here are some guidelines about when and where a concept, in-game tool, or mod would be useful or applicable. It is not exhaustive.

Case Study #1
When I started, I used to apply nifty looking road layouts in traffic jam hotspots just to see if the problem would go away. I did not wait long enough and would swap road layouts in-and-out without clearing the traffic jam. This is clearly a case of not applying Mitigation Step 5: Wait-and-see.

Case Study #2
Do not build your city to incorporate specific road layout/interchange designs at the start. I made this mistake plenty of times (and still do occasionally). Just because you see a neat/cool road interchange does not mean using it anywhere in your city will improve your overall traffic. In the real world, such interchanges arose as an answer to traffic flow problems. Wait for your city to develop traffic flow problems first before choosing a specific road interchange to try out.

Case Study #3
When you notice traffic piling up on your roads, seriously consider HelpCon2. From my own experiences, keeping intersections 20+ cells/tiles apart seem to allow vehicles to sort themselves out. The longer the traffic jam, the more distance between intersections there should be. This will require re-zoning your areas which will cause the Origin and Destination of traffic to change somewhat. Such is the life of any prosperous city.

Caveat: If you successfully reduced a traffic jam by not changing the Origin and Destination zones, you have increased the carrying-capacity of your city. This means you have pushed the current traffic jam further into your city. Expect to deal with more traffic jam hotspots as the game progresses.

(I know. This isn’t what you wanted to hear. But it is part of the growing pains of a healthy city. It is what real city planners have to deal with for growing cities.)

Applied: Difference Between Traffic Jam and Traffic Flow Problem

Am I splitting hairs by differentiating between a traffic jam versus a traffic flow problem? Yes and no.

I define a “traffic jam” as a persistent, long pile-up of vehicles that lead to little or no movement. If your cims are walking faster than the cars to get to their destination, you have a problem.

A “traffic flow problem” is simply not enough cars passing through an area fast enough. If you played enough “Cities: Skylines”, you know the difference.

Remember this?
The circled area is clearly experiencing a traffic flow problem. But it has not escalated to a traffic jam, at least, not yet.

To save myself grief, I ignore it. Applying HelpCon01. Why? I plan on adding more roads and more zones as I grow the city. Each time I do this, I change traffic flow patterns in unexpected ways. Bouncing back and forth too much between reducing traffic flow problems and growing my city is an exercise in frustration. Sometimes traffic flow problem sites clear up as I keep changing my city. Other times, the problem just moves to a different part of the city.

It is just easier to let traffic flow problems become traffic jams and deal with them then. When traffic jams crop up, I do my best to ignore them too. Applying HelpCon01 again. What? But why? In my mind, I am busy growing and managing my city (and following cims around town). I cannot be bothered being a traffic manager, dang it! 🙂

I pay attention to traffic jams when they degrade the city’s traffic such that it cannot make money. Then I apply the Mitigation Steps. If I get tired of growing/managing my city, I will apply the Mitigation Steps just for something to do.

There are no hard-and-fast rules about when to apply the Mitigation Steps. That is up to you.

Applied: Roundabouts Are Great, Right?

This section highlights theory versus application.

When I first read about roundabouts and what they were supposed to address, I thought they were great. And they are (so are the other road layouts). Traffic jams gone, poof! But when applied, results may vary.

The screenshot below shows a failed roundabout. No matter how long I wait, the traffic moves too slow through the roundabout. The long pile-ups never go away!

On the one hand, the 3-lanes in the roundabout are used well. Traffic is distributing itself properly into their exit lanes. For the curious, I used the mod “Traffic Manager: President Edition” to change the lane arrows in the roundabout to improve flow. Despite this, the roundabout fails because the vehicles pile up at the top, right, and bottom roads. Not what I was expecting after reading the good things about roundabouts; I thought roundabouts could handle any kind of traffic flow problem.

On the other hand, when I watch traffic inside the roundabout, I noticed that vehicles from all 4 sides cross to the opposite side. There is not enough road length within the roundabout for lane-changing vehicles to get out of each other’s way. The carrying-capacity of the roundabout is exceeded. And so the roundabout experienced its own momentary jams.

So what can be done in this case? Replacing the roundabout with a larger one is out of the question. Shortening already short lead-in roads to the roundabout would cause traffic jams even before the roundabout. Moving the traffic jam to four locations instead of one makes a bad situation worse. I thought about other fancier road layouts like the embedded windmill. But I settled on the simple 4-way intersection with traffic lights to see how it would fare.

Woo-hoo! In this case, simple works. In the screenshot above, traffic flows much better, illustrated by the distribution of traffic among as many lanes as the roads provide. And it makes good use of the restricted space. Are pile-ups eliminated? Umm, no. Some weeks there are pile-ups, but eventually they clear up all by themselves.

The screenshot below shows a successful roundabout in the same city.

Originally, the roundabout was a 3-way intersection with traffic lights. Long pile-ups existed in the right-most lane of Road A leading into the city. Turning off traffic lights did not help. Road A’s incoming traffic wanted to go to both Road B and to Road C. This caused long pile-ups on Road B’s outgoing traffic.

The roundabout is bigger than the first one shown above. The increased size allows vehicles from all 3 roads to smoothly transition into their exit lanes without interfering with each other.

The lesson learned here is that roundabouts are great, but not for all situations. Knowing about types of road layouts is one thing. Whether a certain road layout will actually reduce traffic jams in a problem spot is an exercise in trial-and-error. Sometimes a simple 4-way (or 3-way) intersection with traffic lights is the best solution.

When in doubt, apply a simple road layout. Then wait-and-see the results for a few in-game weeks.

Applied: Abrupt vs. Smooth Intersections

If an intersection abruptly terminates, like in a T-intersection, traffic will slow down as it makes the turn. This reflects real-life driving behaviour.

Abrupt intersections can cause traffic flow issues, especially if such an intersection connects with a highway. See screenshot below for an example; this is HelpCon09 in action.

In the case of the above highway intersection, the simplest solution is to smoothly integrate the road into the highway. As you can tell in the screenshot below, traffic is starting to space out near the highway intersection. This reflects how smooth lead-in and lead-out roads work in the real world.

The fix does not require mods. However, the mod “Fine Road Anarchy” can certainly help if the spacing between roads is really tight or you need/want ultra-smooth grades for lead-in and lead-out roads.

Applied: Where TM:PE Fails and Where It Is Needed

This is an example of where mod “Traffic Manager: President Edition” (“TM:PE”) is useless (that is, it fails).

Regardless of how I use the Lane Connector tool in “TM:PE” on highway A, traffic bottlenecks in one lane among a 3-lane highway. Ideally, I want at least two lanes to be used. This highway is the main arterial road that lead cims from my city to the outside world.

In order to “fix” this traffic jam, I suspect I have to resort to HelpCon06. By understanding the Origin and Destination of the traffic, I can either reduce traffic at the Origin end or the Destination end in order to improve traffic flow. Reducing traffic on the Origin end will prevent the city from growing since traffic flow is the lifeblood of any city. This is not what I want so HelpCon06 is not that useful, but it is an option if all else fails.

What I probably should do is build another highway that runs alongside highway A (this is HelpCon10). This new highway should be dedicated to shuttling my cims outside of my city as fast as possible. This is a major highway project that requires time to build and a lot of money. Thankfully, my City Treasury has lots of money to buy me that time. With all this money, another option could be building a rail service that ferries cars/trucks from the Origin to as close to their Destination as possible. This would reduce traffic jam on the highway by shunting some of the traffic to rail. In either case, it requires planning and time to execute; this project would likely consume a whole day to get it right.

The traffic flow problem below requires the use of mod “TM:PE”. The vanilla game mechanics cannot help. As you can see on highway A, two lanes of highway traffic are colliding at node b as they both try to drive in the leftmost lane.

Using successive Lane Connector segments chained together along highway A, cim traffic is able to untangle itself. Of course, traffic flow problems now move from highway A to highway B. Ah well, you cannot win them all. This demonstrates what I mean when I say that increasing carrying-capacity on one road segment will move traffic problems to other parts of your road infrastructure.

Applied: Where Fine Road Anarchy Is Needed

For the most part, mod “Fine Road Anarchy” is mainly used for cosmetics and is optional. However, in the screenshot below, we have a case where the mod is absolutely necessary. Without it, the road interchange cannot be placed due to slope restrictions.

With mod “Fine Road Anarchy” engaged, the road interchange can be placed. To me, this interchange is more aesthetically pleasing than the cloverleaf interchange it replaces.

Below is the road interchange properly connected between two city districts and the arterial highway (running left-and-right). The road interchange also exposes which destination zones are collecting more traffic. The top 6-lane road leads into the commercial zone of a city district. The bottom 6-lane road leads to a dedicated industrial zone set far away from any city districts.

Applied: How to deal with this traffic jam?!?

Decided to show you a horrendous traffic jam in one of my cities.

Did my best to ignore the problem for as long as I could (applying HelpCon01) for many in-game decades. Unfortunately, the problem did not go away.

As for as solutions go, I have quite a few choices.

After staring at this area for many days, I realized that HelpCon10 is likely the best concept to implement. My reasoning for thinking this is because the carrying-capacity of the highways have been maxed out (HelpCon07). This is why traffic jams are occurring. In order to increase the carrying-capacity of the highways, I need to provide more interchanges for traffic to leave the city and to enter city zones. This raises the following questions:

• How many interchanges are needed?
• Where should they be placed?; and
• What kind of interchanges should I use?

Quick Tips on Improving Traffic Flow

Here are some general, high-level tips to improve your gameplay. They are in no particular order of importance.

1. Work with the game’s pathfinding algorithm, not against it.
2. Do not predict where traffic flow problems will occur; just react to them.
3. T-intersection is your friend. Fork-it if you need to.
4. Wait for traffic to stabilize BEFORE changing its flow.

To learn these tips, just pick one. Do not try to keep all the tips in your head. Practice the chosen tip a few times on one of your maps. The bigger your city gets, the more chances to practice. Once you feel comfortable applying that tip, choose a different one and practice just that one. In this methodical way, you can integrate it into your gameplay seamlessly.

(1) is easier said than done. Learn to appreciate that the game’s pathfinding algorithm is exposing a pattern that needs addressing. Your job is not to eliminate traffic jams entirely but to reduce them.

(2) saves you stress and frustration. Just know that traffic jams will occur as your city grows. Focus on growing your city. Let traffic jams show up in their own time.

(3) may look ugly/inelegant. But if it gets the job done, that is all that is important. Function over form.

(4) is about looking at persistent problems instead of noticing temporary ones. Sometimes traffic jams will untangle themselves with no help from you. As you grow your city by laying down new roads or re-routing old ones and by zoning and re-zoning areas, you change traffic flow. These changes take time to manifest themselves as potential problems. When traffic jams become so big they cannot be ignored, it is time to stop all changes and just watch. Let the game run for a few in-game weeks/months. See if traffic jam site(s) clear up by themselves. If not, then you know you have a problem that needs addressing.

You will start thinking less and start feeling more about road layouts. That is, certain road layouts will feel right, while others will feel off. And your hunches will be rewarded when traffic jams show up where you felt they would.

Last Thoughts

Feel free to leave constructive criticism if the guide:

• needs more pictures;
• was too vague in areas;
• is missing something that requires explaining;
• used incorrect terminology;
• has typos; OR
• is just plain wrong

I will do my best to update this guide as needed.

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