Any traffic enthusiasts want to give a new player some suggestions?

[rwk219]

I have a neighbourhood of around 36k cims on the north side of a 8 lane non-divided highway and to the south an amusement park. There are bus lines and metro stops working pretty good (I think) and serving both areas. My traffic had been around 80 to 85 but I may have built a bit to many neighbourhoods and commercial zones and now traffic is getting kind of bad. Traffic is now 70%. To me it almost seems like a lane switching problem.

The heavy traffic is travelling East to West.

Here is a picture of the area in question. Much of the traffic is exiting to the on-ramp to the highway. There are 3 main diamond exchanges leading up to it, and then also a T intersection quite close. The T intersection is not busy. The East West traffic gets 30 seconds and then the other road gets 5 to 8 seconds.



Junction 1

This seems to be working as intended. My 6 lane highway changes to 8 lane for the onramp.. The traffic coming from the on-ramp all immediately try to get into the 2nd lane.



Junction 2

Prior to junction 2 all the cars have settled to going to or staying in lane 2. Road changes to 6 lane in between ramps. Then most or all of the traffic seems to want to lane switch to the middle lane (which would have been lane 3 before the interchange). There are no TMPE lane connectors going on at this point, not until the onramp portion of this junction, when they are all directed to go straight, with the onramp getting it's own lane as the highway again switches to 8 lane.


Junction 3

Traffic has stayed or is trying to get into the left most lanes coming up to Junction 3. Highway again switches to 6 lane in between ramps before going back to 8 lane after onramp. The next picture is right after this junction (3) and near the highway onramp where many of these vehicles are exiting.

Near the bottom of this picture is where where so many of these cars are trying to merge to the right for the upcoming right lane exit. Traffic gets bogged down here, many cars are stopping and doing 90 degree turns to lane switch and this slow down is affecting vehicles going back.

From what I can gather after the first junction vehicles try to stay to the right, then they merge left around the 2nd junction, and then they merge right after the 3rd. Perhaps there is an easy solution to this. I'm pretty new to the game, 2 weeks

 

[rwk219]

Upon further research (a few hours worth) I stumbled upon an idea that Advanced AI Dynamic Lane Selection could produce some results like that. I had mine set at 30% but decided to check anyways and found that it was at 0%. I must have inadvertently changed it at some point. Setting it back to 30% seems to have fixed the problem and traffic is back over 80%.

 

[MarkJohnson]

The biggest problem I see is that you have removed the major highways and replaced them with streets.

This will have varying issue as everything in this game is on a timer. Plus streets have traffic lights and signs that slow down traffic as well. Streets have lower speed limits than highways, as well.

In TMPE, it seems the general consensus is that 50% is the sweet spot for traffic AI.

In general your city should be fine for now. But as it grows bigger, it will get more and more traffic.

 

[rwk219]

Thank you for your reply.
As for the main road in the pictures I was sort of treating it as an arterial road with diamond junctions. To the left of the where my picture cuts off there are two separate highways (from the base map, and they met at a T junction, as I recall) that this has access to. Feeding into this arterial are 4 lane streets that pretty much line the outer edges of that neighbourhood and then inside that are simple 2 lane streets. I'm still learning this road hierarchy design though and definitely don't mind being told that I can do it better.
I'll play with adjusting upwards to 50%, thanks for that suggestion. I appreciate your time.

 

[Beer Fiend]

I'd strip out those diamond interchanges and put in roundabouts.

With TM;PE you can use the lane connectors to ensure a near constant flow of traffic.

 

[Ragga Muffin]

I'd strip out those diamond interchanges and put in roundabouts.

With TM;PE you can use the lane connectors to ensure a near constant flow of traffic.

go download a diverging diamond?
Having a metro cutting right through centre of your zoning with some lighter transit to feed the stations will decimate your traffic
As would a frieght line into the commerce from the indy

 

[havenost]

So the thing that most players fail to understand about Cities Skylines traffic is how nodes and lanes work.

A lot of traffic is caused by cars suddenly trying to change lanes all at once. The reason this happens is because cars can only change lanes at each node. So between junctions you have to give cars about 4-5 nodes so they can adequately go from an inner lane to an outer lane. You also want to have segments in between nodes to be adequately long so that cars going straight don't suddenly get cut off and stop by a car merging into their lane at a node.

So if you build a junction entering a "highway", make sure you build any off ramps adequately spaced away from it, that way the on going and off going traffic doesn't cross to the same inner lanes.

I use to make this mistake all the time where I would build junctions only 1-2 nodes apart and wondered why cars didn't the outer lanes of my 6 lane one way highways, and why they all tried to merge into basically 2 lanes.

Nodes = Are the beginning and end points of each segment, they determine where and when cars can change lanes

Segments = the sections in between nodes, their length determine how many cars can be in a lane, especially important when having designate turn lanes