Help Me Fix My Downtown Traffic! :(

[final garnet]

A recent breakdown of traffic in my downtown intersection has resulted in me experimenting with different junctions; currently, I have settled on a large roundabout, which, however, still has its issues.

Traffic patterns in the area have a clear predominance of heavy through traffic, which is being interrupted by competing junctions.

A clog of vehicles entering the roundabout has resulted in vehicles getting stuck behind timed traffic lights at junctions further back

Lane schematic map of roundabout

The main issue is approaching vehicles are stopping to yield to other vehicles in the system already way too far back, I don’t know how to bring this stopping out further up, which would greatly reduce the line of awaiting vehicles

Another HUGE issue is that cars approaching the roundabout that choose to make a right turn are yielding similar to the other lanes, but they have their own dedicated turn lane that other vehicles coming from other sides physically cannot interfere with.

Help Me Fix My Downtown Traffic! :(

I’ve considered canning the roundabout idea all together for a design similar to the following image, however, even with my current design, it’s hard to work around the preexisting monorail and bike path infrastructure which i would like to preserve, as I cannot think of ways to reroute their current paths.

I was going to reroute the monorail tracks over the road with these assets, however I have to elevate them higher than the stations or they will clip with street lights, and that change in elevation doesn’t look the cleanest

[glad wren]

You could tunnel

I think a bigger issue is that if most of the traffic is going through, you want it interacting with as few of the junctions as possible. If possible you should reduce the other local/collector connections to the arterial, and even better if you can preserve connectivity with a bridge, even if it's just ped/bike

[final garnet]

I agree, however, in the past when I removed a majority of junctions before the roundabout, it actually worsened traffic, but that was when I had a much smaller roundabout configuration, so I’m going to go back and try again. Thanks for the suggestion.

[orchid lily]

I would setup timed traffic lights at the roundabout.

That’s how it’s done IRL here in The Netherlands

And it works in game

[final garnet]

Tunneling would be nice, but at the junction pictured, one road goes above and one goes below, so if they were to both go underground, each road would have to differ in elevation so as not to interfere

[final garnet]

I’ll try that as well

[orchid lily]

If you want to see an example of a perfected roundabout https://youtu.be/74nvIezQjco

[ember trellis]

A few thoughts:

Change the main cut through road into an aerial arterial with no conflicting movements, only right on/off ramps on both sides going down to the local grid. Space these out, maybe 3 or 4 on the island.

Add extra bridges to the island so not all through traffic has to use that one road. Will help distribute local trips.

[ember trellis]

This will allow for local grid connectivity under the main road.

It may be a peninsula, not an island, but same concept.

[heady portal]

I had a similar intersection/roundabout in my city and I found that by placing the overpass bypass on just the most heavily used direction completely fixed the problem. If there's more east-west straight through traffic on yours than there is north-south, then you could underpass the east-west only leaving the rest as-is. You may find that removing that bulk of straight-through traffic allows the rest of your roundabout to function efficiently enough

I also really like PlannerPete's suggestion of elevating the arterial

[final garnet]

I actually looked at that one lol

[final garnet]

Yes, I need to be cautious of shipping lanes though, and it’s not an island, simply a large river with highway access on the other side

[final garnet]

Aerial infrastructure is hard to implement in the area due to other elevated forms of transportation, that’s one reason I haven’t gone this route yet, but it may be necessary

[final garnet]

That’s smart, there is not much demand for north-south traffic, only east-west, so in that photo of inspiration I could only have one road direction tunnel (east-west) and the other just meets at an intersection, rather than one bridge and one tunnel, which would disturb monorail infrastructure

I think it may have gotten to the point where I need to rework my monorail system lol, it’s the main setback on this whole process

[heady portal]

you can even leave the intersection as a roundabout since the VOP actually works with them too. I'll see if I have a screenshot of my intersection as an example

[heady portal]

Feel free to ignore my totally realistic pedestrian pathways lol. Underpass would work basically the same as this too

[final garnet]

That looks amazing, I’ll have to try it

I haven’t used VOP yet but I have the assets, J think you’re configuration is great, 1-4-1

If there’s the options I might try 2-4-2

I don’t know if I would do a normal or turbo roundabout

[heady portal]

All I can say for VOP is to watch every tutorial you can find. Several times. And practice. They can be a pain to get right sometimes but very very worth it in the right scenario

I just did normal roundabout in my location, but I suspect it had lower volume than yours. I literally didn't even mess around with any Hugo-There™️ just lane arrows and it works fine for me. If you do 2-4-2 I'm sure a higher volume turbo roundabout would work great

[ember trellis]

VOP?

[final garnet]

Vanilla Overpass

[final garnet]

Tried the 2-4-2 configuration and removed junctions previously pictured, got traffic flow up to 79% from ~73%, will definitely be implementing permanently in my main save

85% now!

92%!

Might actually do the 2-2-2 configuration

[heady portal]

Oh sweet!!!