I’ve got bad news for you: fixing your roads to prevent traffic jams is something you’re going to be doing for however long you play Cities: Skylines II. It is a problem that just grows and grows as your city does.
A specific street might be perfectly fine one moment, but after you plop down something new on the other side of town, it gets clogged up. But there are ways to fix it. Just make sure you’re keeping an eye on your traffic infoview.
The basics of roads
The best advice I’ve received about good road design is that roads are like the human circulatory system. You have your highways, which are like arteries. They’re your biggest vessels where blood flows the fastest and needs to be unobstructed. Then there’s the collectors, which are like your veins. Finally, you have your capillaries, which deliver the blood to its destination.
With that in mind, you want to ensure that you don’t just have a single highway offramp. Highways are extremely important for people and cargo coming into and out of your city, and the closer you can deliver them to their final destination, the better. If they have to take a longer route using your smaller roads, then that’s more traffic on systems that don’t support large volumes.
Collectors are your larger roads that connect your traffic to highways. They’re called collectors because they collect traffic from your more basic road systems. Traffic should flow as freely as possible here, which generally means that you should have as few intersections as you can possibly manage.
Finally, there are your roads which you should use to deliver people to their residences and places of work. While these are going to be the most utilized type of road in your city, you should ensure that they’re spread rather evenly. You can use them to place facilities, power plants, and parks because those places only receive light traffic. With that in mind, avoid placing sports stadiums and tourist spots on roads, because they draw traffic to them.
You can find a breakdown of the road types here.
Ditch the grid
Okay, not entirely. However, using a grid of streets to keep your city organized can cause a lot of problems because that’s a lot of intersections. Intersections are a necessary evil in that they are required, but you should use them sparingly.
If you do use a grid, try to only place locations that draw low traffic. This would be your higher-density residences, offices, and industries. Then, connect the grid to your collectors with as few streets as possible. This means if you have a grid, don’t just build it directly against your larger roads. Build them off to the side, then connect them with only a few roads to minimize the intersections on your collectors.
You might look at the real-world Manhattan as an example of grid streets in a major city, but have you seen the traffic in New York City? Not a good role model.
Use roundabouts
In reality, roundabouts are statistically proven to reduce traffic accidents and maintain the flow of traffic. However, Big Intersection would rather you didn’t believe that.
In Cities: Skylines 2, they can be just the ticket to avoiding gridlock. Cars only need to slow down when entering a roundabout as opposed to an intersection where they’re forced to stop entirely. You don’t have to use roundabouts to replace every single intersection, but they are useful for where your collectors intersect each other or where highways connect with your collectors.
One thing to note is that you may need to pay attention to your lanes when placing roundabouts. In the image above, you can see the lane directions painted on the road. Only one of them can make a right turn. I once placed a three-lane highway that connected to a roundabout as part of an incomplete traffic project. Despite the roundabout only having a right turn, the roundabout only allowed one lane to use it, which resulted in the offramp becoming extremely backed up as everyone tried to cram into one lane. I had to destroy and adjust it to get the lanes to work right. It’s a weird issue that might not happen to you, but it’s worth noting if you can’t figure out why traffic is jammed up against your roundabout.
Highways!
I’ve already said this once, but your highways are the absolute most important part of your road system. Most maps start you off with one major highway stretching across the landscape, but don’t stop there. You need your highway to feed every part of your city. The easiest way to do this is with a “highway loop” that encircles your city. Considering there are only two ways out of your metropolitan area, I think the loop is rather effective. However, it doesn’t hurt to intersect across your city in order to feed more of your boroughs.
Just make sure that you have enough on/off ramps. The more, the better. Highway intersections take up a lot of space, but they’re necessary to prevent buildups on your collectors and city streets.
Public transportation and freight
A very effective way to improve the flow of traffic is to reduce how much traffic you have in your city. More pedestrian paths help, but the more likely answer is public transportation. Busses, trams, and especially subways will help keep your citizens from having to drive everywhere. Unfortunately, building effective public transportation is actually more complex than building roads. I’m personally still learning how to do it, but it’s a topic for a completely separate guide.
Cargo is a lot more simple, however. If you use cargo trains and connect them with other industrial areas as well as connections with other cities, it will reduce how much your industry relies on using roads. This goes for cargo ships and planes, and even highway onramps. Build your industry close to these, or build these close to your industry. The less your industry needs to cross your streets to make deliveries, the better.
Maintain your roads
My last tip for you is one that’s easy to overlook. Your roads have a “condition” statistic to them that deteriorates with use and other factors. A road that is in bad shape will cause more accidents, and traffic accidents are a good way to destroy all your efforts.
One road maintenance building covers a wide area, so it’s easy to just drop one down and forget they exist while your city grows. Likewise, you might not see much benefit in keeping a big budget for your roads. Cutting funds and not covering your territory will result in bad roads, more accidents, and more gridlock. You can check road conditions using the road infoview.
