Roundabouts are bugged

[Hobby Boy]

Normally, the traffic should always flow inside of the roundabouts, and the vehicles on the inside don't give way to joining vehicles. However in Cities Skylines, the traffic just stops in the middle lane, effectively gridlocking the roundabout. The cars aren't going into the inner lane either.

http://steamcommunity.com/sharedfiles/filedetails/?id=410073195

That is the worst of the traffic on a roundabout in my city, but its also happening on my motorway junction roundabout as well.

[impreza7]

Traffic chooses lanes very early in this game. It's a pain, but is predictable.

Therefore: You need to force some of the traffic to exit/enter from the inside of the roundabout. Use a ramp and loop 2 of those roads to the inside of the roundabout. Also, 5 major roadways converging in one roundabout is too many.

[SabreXT]

Having the same problem, and turning roundabouts into a tangled mess kind of defeats the purpose. :/

[Nellvan]

This again. "Normally" does not apply since there's lots of different ways to do a roundabout.
I could say "normally" there are almost no roundabouts in a city, and they are huge and have traffic lights on them. Cause that's how it is where I live.

Originally posted by impreza7:

Traffic chooses lanes very early in this game. It's a pain, but is predictable.

[-Fields-]

Yes the picture shows a prime example of a problem BUT maybe explore what is causing the issue furter along, maybe try and make a new route from where most of the traffic comes from to the destination direction, it might be time to provide a alternative route for the traffic, for example take the traffic from the north away and keep this for the traffic from the south.

[BlackAlpha]

Originally posted by Hobby Boy:

Normally, the traffic should always flow inside of the roundabouts, and the vehicles on the inside don't give way to joining vehicles. However in Cities Skylines, the traffic just stops in the middle lane, effectively gridlocking the roundabout. The cars aren't going into the inner lane either.

http://steamcommunity.com/sharedfiles/filedetails/?id=410073195

That is the worst of the traffic on a roundabout in my city, but its also happening on my motorway junction roundabout as well.

The vehicles in the middle lane want to get to the left lane, but the left lane is full, and so they wait. The other cars use the same logic and so everybody stops. The cars are unable to recognize that there's space on other lanes if they move around the vehicles that have stopped.

The issue lays not just with the roundabouts, but with all roads that have more than 1 lane into a certain direction. The vehicle AI does not know how to make good use of all lanes.

Therefore, increasing the amount of lanes won't solve the issue.

For us, the only way to fix/circumvent this is to solve the traffic jam in another way. In most cases, it means you have to spread out the traffic over a larger area (less bottlenecks). So, instead of having a roundabout with a fixed direction, create a simple box using two lane two way roads. That way you can spread out the traffic. And if it does become crowded, at least they won't gridlock themselves.

Example:
http://i.imgur.com/zRM9Ftb.jpg
http://i.imgur.com/5297tBb.jpg

Preferably, you do not want that much traffic to go through that single area. So give them another route through a different area.

[SabreXT]

Originally posted by BlackAlpha:

Originally posted by Hobby Boy:

Normally, the traffic should always flow inside of the roundabouts, and the vehicles on the inside don't give way to joining vehicles. However in Cities Skylines, the traffic just stops in the middle lane, effectively gridlocking the roundabout. The cars aren't going into the inner lane either.

http://steamcommunity.com/sharedfiles/filedetails/?id=410073195

That is the worst of the traffic on a roundabout in my city, but its also happening on my motorway junction roundabout as well.

The vehicles in the middle lane want to get to the left lane, but the left lane is full, and so they wait. The other cars use the same logic and so everybody stops. The cars are unable to recognize that there's space on other lanes if they move around the vehicles that have stopped.

The issue lays not just with the roundabouts, but with all roads that have more than 1 lane into a certain direction. The vehicle AI does not know how to make good use of all lanes.

Therefore, increasing the amount of lanes won't solve the issue.

For us, the only way to fix/circumvent this is to solve the traffic jam in another way. In most cases, it means you have to spread out the traffic over a larger area (less bottlenecks). So, instead of having a roundabout with a fixed direction, create a simple box using two lane two way roads. That way you can spread out the traffic.

Or to put it simply, roundabouts are bugged. :P

But the problem isn't the lanes themselves. As you can see, there's lots of ways out, and in my case, the traffic wanting in is made much worse by them grinding to a halt. You can fix it somewhat by creating spokes as impreza7 said, and I assume your box of 2 way roads might works, though I've not tried it at time of writing.

If the point of roundabouts is to keep traffic flowing at major junctions, and it's possible to get the same effect by tricking the AI into working as it's supposed to, that shows there's a problem with roundabouts.

[BlackAlpha]

Originally posted by SabreXT:

Originally posted by BlackAlpha:

The vehicles in the middle lane want to get to the left lane, but the left lane is full, and so they wait. The other cars use the same logic and so everybody stops. The cars are unable to recognize that there's space on other lanes if they move around the vehicles that have stopped.

The issue lays not just with the roundabouts, but with all roads that have more than 1 lane into a certain direction. The vehicle AI does not know how to make good use of all lanes.

Therefore, increasing the amount of lanes won't solve the issue.

For us, the only way to fix/circumvent this is to solve the traffic jam in another way. In most cases, it means you have to spread out the traffic over a larger area (less bottlenecks). So, instead of having a roundabout with a fixed direction, create a simple box using two lane two way roads. That way you can spread out the traffic.

Or to put it simply, roundabouts are bugged. :P

But the problem isn't the lanes themselves. As you can see, there's lots of ways out, and in my case, the traffic wanting in is made much worse by them grinding to a halt. You can fix it somewhat by creating spokes as impreza7 said, and I assume your box of 2 way roads might works, though I've not tried it at time of writing.

If the point of roundabouts is to keep traffic flowing at major junctions, and it's possible to get the same effect by tricking the AI into working as it's supposed to, that shows there's a problem with roundabouts.

Yes, it's a problem with roundabouts, four lane, six lane and highway roads.

I updated my previous post with some screenshots. Try something like that. But also try to heed the advice in the bottom of that post, that is the most effective way of solving traffic problems.

[impreza7]

it's not just roundabouts, it's all the traffic. They want to get in their lane NOW, even if their exit is 50 miles ahead. All we can do is trick the game into doing what we want....

One thing I usually do when making big highway changes is to delete a critcal part of the highway and let the traffic despawn and clear out a bit. This gives u a fresh start on traffic flow instead of traffic trying to adapt on the fly. I know this isn't much help, but it is what it is for now

[BlackAlpha]

Because of how the traffic AI works, the best way to solve traffic problems in this game is to imagine the traffic only has one lane at their disposal, no matter what type of road they are on. In most cases, if you can solve the problem by using four lane, six lane or highway roads, then you can probably also solve it by using one lane roads instead.

[Fronto]

There are no roundabouts in this game; there are only circular roads with intersections on them. If you keep this in mind things get easier.

[ohener]

I've noticed they seem to work better if you only connect to them with 1-way roads. As for the picture in the OP, the drivers are only using one lane because all the roads that lead to it only have one lane.

[TaterShovel]

http://i.imgur.com/F8eKjp5.jpg

That picture opened my mind.

[impreza7]

Originally posted by Vince:

There are no roundabouts in this game; there are only circular roads with intersections on them. If you keep this in mind things get easier.

Excellent point, wouldn't it be cool to be able to send your Sims to traffic class? Or just have driving abilities upgrade with education.

[try2bcool69]

Originally posted by impreza7:

it's not just roundabouts, it's all the traffic. They want to get in their lane NOW, even if their exit is 50 miles ahead. All we can do is trick the game into doing what we want....

One thing I usually do when making big highway changes is to delete a critcal part of the highway and let the traffic despawn and clear out a bit. This gives u a fresh start on traffic flow instead of traffic trying to adapt on the fly. I know this isn't much help, but it is what it is for now

Actually, it's just the opposite. The reason why they all end up in the center lane is because they won't get over into a turn lane until they pass they last intersection before the one they want to turn at. The more intersections there are, the worse the problem is. They will wait in that middle lane forever. I don't understand why they made the AI do that, they should change it so that vehicles get in the lane they are going to turn from, ASAP.

[BlackAlpha]

Originally posted by try2bcool69:

Originally posted by impreza7:

it's not just roundabouts, it's all the traffic. They want to get in their lane NOW, even if their exit is 50 miles ahead. All we can do is trick the game into doing what we want....

One thing I usually do when making big highway changes is to delete a critcal part of the highway and let the traffic despawn and clear out a bit. This gives u a fresh start on traffic flow instead of traffic trying to adapt on the fly. I know this isn't much help, but it is what it is for now

Actually, it's just the opposite. The reason why they all end up in the center lane is because they won't get over into a turn lane until they pass they last intersection before the one they want to turn at. The more intersections there are, the worse the problem is. They will wait in that middle lane forever. I don't understand why they made the AI do that, they should change it so that vehicles get in the lane they are going to turn from, ASAP.

Because the AI will not change lanes if the lane is blocked. So, if you would do it the other way around it would cause problems as well. The car would go early into the left lane, even though it needs to go straight ahead. If the left lane happens to be blocked by vehicles trying to go left, the car will need to wait until the vehicles going left went left. Only after that, will the car continue going forward.