Cities Skylines Traffic Tips

Cities Skylines Traffic Tips by Matt8D

Some tips and tricks for managing traffic. This guide will help you understand the basics of traffic in C: S.

First, let’s dispel a common misconception: Traffic isn’t broken. In fact, it’s perfect. Cars will always go the fastest route, being as efficient as possible. If you’re aware of this it’s easy to evade those perceived bugs. Now on to the guide!

Understanding the AI

The AI’s path is determined before it gets on the road. It looks for the fastest time to it’s destination, factoring speed and distance. The lanes it will change to and when, the turns it will make, all pre-determined. The AI is not aware of the current traffic situation on any road.

The AI will prioritize their lane depending on where they are going to exit the road. If their turn is immediate, they will choose an outer left/right lane and make their turn. If their turn is farther down the road they will remain in a middle or left lane until they approach their intended turn. If too many cars are using the same exit point on a road, they will all funnel into one lane and likely cause those odd backups.

Being aware of where cars will be exiting large roads is key to preventing disasterous traffic jams.

Roads and their purposes

Cities: Skylines has just a few types of road, and they each have their own job.

– 2-way city roads: These roads get you from your building (house, workplace, etc) to a larger road. Since 2-ways are slow, they’re not suitable for long distances. One should only need to travel on a 2 way road for a couple of blocks before reaching a faster road.

– 4-lane and 6-lane roads: These avenues will connect your neighborhoods to your highways. Generally you want only one connection per neighborhood. In the denser areas I tend to consider every 2-3 blocks a neighborhood. In low density they’ll be larger.

– Highways: For inter-district connections. These cause pollutions and noise so they will lower land value around them. You’ll often want these raised so local traffic can flow beneath. Only connect to the larger roads.

– Off Ramps: Off ramps are used to get cars on and off the highways efficiently. Off ramps tend to be the biggest traffic problem areas.

So the flow to any destination should be as follows: Starting Building > Local road (Neighborhood) > 4/6-lane road (Your avenues/highway connection) > Highway > Off onto another Avenue > Neighborhood > Destination
If you drive in real life this should look familiar. You’ll almost never run into an unsolvable traffic issue if you keep this flow in mind during planning.

Intersections and Roundabouts

Intersections with lights will hold up traffic, and are usually pretty darn inefficient. Reducing intersections or replacing them with roundabouts will reduce traffic. Here’s a few tips at reducing the number of intersections in your city depending on the situation:

– In Neighborhoods: In high density areas, your neighborhoods (2-3 block sections of buildings) will have lots of crossing 2 lane roads. 1-way 2-lane roads will not create lights as frequently as a normal 2-lane. You’ll want to convert as many roads in these neighborhoods to 1-ways as you can. If using a grid pattern, you can just alternate the one-ways direction every block, and have 2-ways intersecting them. Practicing with one-ways will make inner-city traffic flow so much easier to manage.

– On Avenues: Traffic lights on your avenues are a nightmare for flow. The good thing is that a 1-way, 2-lane road coming off of a 4/6-lane avenue will not create a light. You can use that to have more connections into a neighborhood without sacrificing efficiency. Having 2 or more connections into a neighborhood(s) and then one larger connection out of it will mean only one traffic light for a longer stretch of avenue. In my experience, a larger intersection is more efficient than many small ones. When 2 or more avenues meet, USE A ROUNDABOUT!

– Connecting to Highways: I usually use a roundabout to connect my avenues to my highway ramps. doing this prevents cars using the off-ramp from getting stuck at an intersection, and piling back up onto the highway resulting in MORE cars being delayed. If you don’t have the option, just upgrading the off-ramps to a 2-lane 1-way where it meets the avenue can speed up the flow of the intersection.

I always use a roundabout if there’s ever a 5+ way intersection. If it’s multiple busy roads, I’ll use a walled highway instead of a 2-lane. If it’s more than 5 SUPER BUSY roads connecting in one spot (A worst-case scenario that should be avoided at the planning level) I’ll have all connections ONTO the roundabout funneled over it and into the inside lane and all connections off of it connected on the outside lane. It’s a big mess to do that though, even if it looks cool.

Other little tips

– Upgrade roads to more lanes right at an intersection. This lets cars fan out a bit, reducing the traffic line.

– Make off ramps longer than you think they need to be. A short off ramp in a busy section will usually lead to a line on the highway, which holds up traffic for other cars.

– Make sure there you balance the frequency of intersections on your avenues. Too many and cars will be held up too often, too few and the intersections will have too much volume.

– PUBLIC TRANSPORTATION. Less drivers on the road = less traffic.

– Foot paths. People will walk if they have a safe path to their job. Again, less drivers, less traffic.

Interesting and Novel Solutions

These are some things that are specific-case solutions that I find interesting, or unique to this game. Please share if you have one!

– Use the highway ramp as an elevated high-speed 1-lane connection between two busy areas. If your city is already crowded and in need of a connection between two places this can be a space efficient method to get cars moving. They are 100kph, remember!

Thanks for reading! Hope this was at least the tiniest bit insightful for someone out there! I would love feedback, as I’m not quite an expert at writing guides.
Thanks!