I have no idea what more I can do to alleviate traffic

[JerJer]

My entire city is all 6 lane one ways with multiple roundabouts. Intersections, no matter how infrequent, are just killing everything. My roundabouts are backed up because of an intersection 5 blocks up that i have no way to really avoid having. I mean, streets are going to have intersections, there's no way around it. I have plenty of bus lines. I have a metro. I don't get it.

 

[ItalianGuy]

Try to avoid bottlenecks. For example, if you have a district with a connection to the freeway, create more connections to it in strategic points.
The most important thing of a road isn't the width, it's the variety of destinations.

 

[SkyLiner]

Check out this How To Traffic guide, it has some excellent advice: http://imgur.com/a/z1rM1

 

[MaxxPower]

How many imports/exports do you have?

In my experience, industry causes the most traffic problems, so i try to have as little imports/exports as possible. Not more than 2000 combined.
If you have too many imports, build more industry. If you have too many exports, de-zone some industry. If you have too much of both, you most likely need to fine turne your specialized industries.
Also a outside train connection for your industry, helps bringing some of these trucks off the road.

Maybe you can post some screenshots of your problem?

 

[Person012345]

My entire city is all 6 lane one ways

This is most likely your issue. Traffic lights kill traffic flow, get rid of the 6-lanes and replace them with 2 lanes (especially if traffic is predominantly only using one of the 6 lanes). I'd also advise not clumping things too much, and give traffic plenty of ways in and out. If you have 1 road leading from an industrial sector to a highway and it has traffic lights, every single car, lorry and van trying to get in or out of that sector will have to pas through those traffic lights and as I already mentioned traffic lights are literally hitler.

 

[barrygreybeard]

or maybe post a saved city? it could be any of the above or even all of them. the layout of your city is also important, if the journeys everyone makes has to be across several tiles then that can snarl up even the motorways

 

[JimmiG]

This is most likely your issue. Traffic lights kill traffic flow, get rid of the 6-lanes and replace them with 2 lanes (especially if traffic is predominantly only using one of the 6 lanes). I'd also advise not clumping things too much, and give traffic plenty of ways in and out. If you have 1 road leading from an industrial sector to a highway and it has traffic lights, every single car, lorry and van trying to get in or out of that sector will have to pas through those traffic lights and as I already mentioned traffic lights are literally hitler.

Yes, the natural reaction when you get a traffic jam is to upgrade the road with the traffic jam. This doesn't really solve the problem, and it's even less effective in this game because of the way lane switching works.
I use 6-lane roads only as ring-roads or bypasses, with as few traffic lights as possible, when there isn't enough traffic to justify a highway. Roads work the best within neighborhoods, because they don't create traffic lights.
https://i.imgur.com/rS0WX2g.png

 

[ItalianGuy]

I agree with JimmiG. If a road sector is congested you shouldn't upgrade it, you should look for the bottlenecks following it and see if it's better to create more lanes or an alternate route.

 

[ellindsey]

4 and 6 lane roads are a trap. They are useful in some situations, but heavy use of them results in a lot more intersections than other roads. Cims aren't smart enough to use the extra lanes, they tend to all clump in a single lane so the extra lanes don't help much. You are better of making heavy use of 2 lane roads, 1-way and 2-way chosen carefully to minimize the number of intersections and maintain constant traffic flow in and out of areas.

 

[golden.radish]

I've found with 5 different cities now, using roads only, after 50k-70k population, the roads are congested, even if you do your best to use the 'artery' or 'hierarchy' or 'regional/connecting/local' ideas.

For me, the only thing that works is completely segregating all population areas by using the subway. As in, the roads don't connect (they loop back on themselves), and the only way for cims to get from one "area" to another is by taking the subway.

The only outstanding issue is: "No goods to sell" in commercial areas, which a cargo train may satisfy. More testing!

 

[Person012345]

I've found with 5 different cities now, using roads only, after 50k-70k population, the roads are congested, even if you do your best to use the 'artery' or 'hierarchy' or 'regional/connecting/local' ideas.

For me, the only thing that works is completely segregating all population areas by using the subway. As in, the roads don't connect (they loop back on themselves), and the only way for cims to get from one "area" to another is by taking the subway.

The only outstanding issue is: "No goods to sell" in commercial areas, which a cargo train may satisfy. More testing!

Don't use "only roads" (although you probably could), don't use "only public transport", use a mixture of both. My city of 70k has no traffic issues.

 

[IVIaarten]

Another thing you could do if you're getting traffic issues is not increasing capacity with extra lanes, but use extra speed.

I've been very successful avoiding jams with laying out main distribution roads with highway ramps. The speed limit here is 80, instead of the 40 on roads, so they have twice the capacity.

Also, avoid building too many intersections, they mess up traffic. Instead, set up your roads in a tree-like fashion (from the main tree trunk (highway), have only a couple of main branches (highway interchanges). Each branch splits up into thinner branches (maybe avenues), and the to even smaller branches (roads).

Here's some pictures from my '2 lane highways' which I use as distribution lanes (big branches).

Some maps of my city (highway is blue, my 2 lane distribution roads orange, avenues are yellow, and normal streets white (one ways are gray, dotted is pedestrian paths... use those!)

My city is currently over 80k pop, not a single jam in sight. Also, I'm not using any metro lines at all.

another interesting detail, I only have 5 highway interchanges over the full 10km length of the map. Only 3 of those are close to my main city.

 

[JerkyJerry]

Great pics IVIaarten!
I use nearly the same type layout.
See how those long stretches of roads have no buildings on them? In doing so that will prevent a lot of the turn into, get out of shops, homes, businesses and allows traffic to move into and (sometimes more importantly) out of the city.
GREAT PICS!

 

[Person012345]

Increasing speed is one of the best ways of increasing capacity in real life too. With no crashes in skylines it works even better. And that doesn't mean just the raw speed limit, 6 lanes aren't better because they have a higher speed limit, they're worse because they create traffic lights which stop traffic.

 

[IVIaarten]

Great pics IVIaarten!
I use nearly the same type layout.
See how those long stretches of roads have no buildings on them? In doing so that will prevent a lot of the turn into, get out of shops, homes, businesses and allows traffic to move into and (sometimes more importantly) out of the city.
GREAT PICS!

Yep, that's another great tip; avoid zoning along your main through-routes. Traffic turning into those buildings (especially with industrial or commercial with the deliveries) will put even more strain on your roads. If you put some pedestrian paths along those through-roads, it will look great, and you'll not loose too much zoning space.

something like this:

 

[golden.radish]

I tested the cargo train in commercial, and it works. I have no interconnections, only one small incoming/connection highway loop to connect to the subway, and the rest of the areas are one way self-contained loops, disconnected from all other loops. Working great so far. Steady population growth, full service coverage, buildings leveling to max, etc.

It's also awesome to see so much pedestrian traffic. They're like hordes of ants!

 

[raresteak]

Upload your save to the workshop or post some screenshots. Let us have a look.

 

[Black_Shade]

Another thing you could do if you're getting traffic issues is not increasing capacity with extra lanes, but use extra speed.

I've been very successful avoiding jams with laying out main distribution roads with highway ramps. The speed limit here is 80, instead of the 40 on roads, so they have twice the capacity.

Also, avoid building too many intersections, they mess up traffic. Instead, set up your roads in a tree-like fashion (from the main tree trunk (highway), have only a couple of main branches (highway interchanges). Each branch splits up into thinner branches (maybe avenues), and the to even smaller branches (roads).

Here's some pictures from my '2 lane highways' which I use as distribution lanes (big branches).

Spoiler

Some maps of my city (highway is blue, my 2 lane distribution roads orange, avenues are yellow, and normal streets white (one ways are gray, dotted is pedestrian paths... use those!)

My city is currently over 80k pop, not a single jam in sight. Also, I'm not using any metro lines at all.

another interesting detail, I only have 5 highway interchanges over the full 10km length of the map. Only 3 of those are close to my main city.

How did you make the last 2 screenshots? I like that look to see the infrastructure layout.

 

[IVIaarten]

How did you make the last 2 screenshots? I like that look to see the infrastructure layout.

Used this mod: http://steamcommunity.com/sharedfiles/filedetails/?id=416064574 to export the OSM file
Then open the OSM file in JOSM Editor (JavaOpenStreetMap Editor) to make the screenshots.

 

[panzermuffin]

Would it be possible for you to upload you city, IVIaarten? Your concept is pretty epic and well thought out!