round abouts would be good
#Traffic problem
keen terrace
also maybe removing traffic lights if you have them on
also if possible more access routes to/from the highway
lapis sierra
I'll see what can be done
lapis sierra
made it somehow worse
keen terrace
o
i aint a professional city skylines player but what i usually do when i see that is put an off ramp on multiple parts of the city, it fixes it sometimes, sometimes makes it worse
loud wave
Roundabouts are not the magical cure-all. The problem you have here is probably multi-fold, but the cars would move better off the highway if they didn’t have to turn left. I would remove the ramp that is backed up along with the one across the surface road, and construct a loop that turns the problematic left turn into a right turn off of the ramp, and have a new ramp that runs onto the highway around it.
keen terrace
now thats a professional
loud wave
I also think your first intersection from the highway is too close. This will cause problems especially if both intersections are signalized. The next one has a dog leg on the side street just before it too…so I would recommend removing both these intersections…or at least banning left turns at them if you’re using TMPE. This could cause bottlenecking elsewhere on your grid though…it’s hard to say without a wider map of the city as well as a zoning map.
lapis sierra
here's the entire city so far
and here's the zoning map
it's a vanilla build
but the intersections were prebuilt with mods
lapis sierra
something like this?
dusty flume
I think that could work pretty well
cerulean iris
In looking at the larger view of your whole city, to me it seems like you almost have too many side streets connecting to your arterials. It does look like you've got a good general idea road hierarchy though
By having every single one of them connect to the arterial, your cims have no motivation to actually use the arterial for what it's supposed to be used for and instead they will cut through your neighborhoods on side streets. The pathfinding AI is a bit less than perfect this way
Take just that central grid for example: If it were my city, I'd have one connection to the arterial on each short side and probably two on the long side. I always make these connections at least two or three blocks away from any major interchange if possible. For the arterial connection I always upgrade that section to 2 lanes each way so they have dedicated turning lanes when coming in and out of the grid, and I often extend that connecter two blocks in with no zoning.
It seems counter-intuitive, but this setup makes it super easy for anyone whose actual destination is in the grid to access it, while making it annoying to navigate for everyone else so that the AI forces them to take the arterials closer to their actual destination
hope that makes sense, i can post a pic from my current city in a bit
cerulean iris
here you can see how i have major grids with only a few connections to the arterial. In two places you can see the connector road (in red) go two blocks into the grid, with the internal grid road connecting up over that connector
I know it's not uber-realistic for what you see in most cities, but the game's AI seems to like it. I don't know if it's the right answer, or if it scales well past 90k population, but it has worked very well for me - consistently over 80% traffic flow with de-spawning always turned off
When I check vehicles' destinations using the in-game tool, basically nobody is going into the grid unless they need to. IMHO cars cutting through one area to get to another are the single-biggest cause of unnecessary traffic in this game
anyway sorry for the long messages, hope this helps. otherwise just ignore me lol
loud wave
something like this?
I think that turned into a parclo with two more ramps to facilitate the industrial movement would really help here.
loud wave
In looking at the larger view of your whole city, to me it seems like you almost...
I will also say I agree with you that the first intersection is too close to the highway interchange, but I will disagree with you on your diagnosis of the problem being cut-through traffic/AI pathfinding and your solution being such strict road hierarchy throughout the city—though I do think some road hierarchy will help with the industrial area. I think too much general CS traffic advice focuses on the road layout when the story is really the zoning layout—I’ll explain:
I asked for the zoning map and I instantly see that there’s a modestly sized industrial area. It’s in a pretty good place— @lapis sierra did right by zoning it near two highways AND a rail terminal for easy long-distance access without crossing other neighborhoods—plus connecting pedestrian paths so workers could cross the highway.
Seeing the zoning map I’m actually really impressed that the traffic near this highway interchange isn’t a whole lot worse! There’s actually a lot of good design here.
So while there may be some cut-through traffic, that’s not going to be significant. I would argue that the grid is actually saving a lot of car trips because cims can easily walk from the residential neighborhoods to go to work in the factories—and that’s a VERY good thing.
The problem here is the trucks—an industrial area this size is going to send and receive a good amount of them! Another smart thing you did was spreading your commercial zones out along the arterials—and most of that is along an outer road that follows the waterfront. Bigger roads easily handle the extra traffic commercial generates, and having them spread out with all that residential around put everyone pretty much within walking distance of shopping. So you’re saving a TON of car trips both for work and shopping with the grid. Separating the grid from the arterials as @cerulean iris suggests break the walkability and force more driving. You could replace most of those streets connecting to the arterials with pedestrian paths, and that might actually force more walking and bicycling—but I wouldn’t recommend eliminating many streets through the industrial area. This would create a traffic funnel that would cause unintended bottlenecks getting out along the waterfront. I think the only things I would change are:
1.) beef up the highway interchange to a parclo or a SPUI (if you have mods—TMPE will let you implement the proper traffic light configuration) because that interchange is the only highway access for this neighborhood. The rail terminal takes a lot of pressure off this interchange, otherwise I think this traffic would be so much worse.
Btw, I think you have enough space for the parclo.
2.) the only other thing I would change is making sure that first intersection from the highway into the industrial neighborhood is at least 20-30 units from the nearest traffic light. This allows enough room for lane changes. I would probably widen the road and (if you have TMPE) have dedicated left turn lanes to make traffic move through easier.
I would keep the grid though—there are huge advantages to it. But you’ve just got to make that interchange work more freely and I think a lot of your problems will clear up. If you have TMPE, I think a lot could be solved by just banning left turns at the first intersection. Right turns are good, but lefts will mess things up.
loud wave
I think this is how I would start out. I don’t even think you need a full parclo. Eliminate the one ramp on the diamond, put in a loop that lines up with the side street—this will reduce congestion on that side street.
Then, either ban left turns at the first intersection or eliminate it completely, and straighten out the next one and have a traffic light there. Also, widen to have a 3rd lane going down from the interchange and having left turns. I think this will make a huge improvement. It won’t be perfect—but it’ll work well.
loud wave
Thanks for help everybody 🫡
I think this was a great discussion! In general, I’m not a huge fan of road hierarchy. I think too often it’s assumed to be the solution, when it also opens up a lot of problems as well—namely for walkability.
lapis sierra
I think it's worth mentioning that this is my second city I've ever built
CPP videos are great for learning
loud wave
Yes! He makes very functional cities! Lots of creators just don’t pay attention to function I don’t think…I’ve always appreciated that about his builds. I really enjoyed working on Verde Beach.
Oh…one more thing…I would eliminate that tunnel going under the highway. I think it might be good to have more connections across the highway, but they would probably be more effective when at least a little further from the highway crossing at the interchange.
lapis sierra
It's only a temporary solution
cerulean iris
oh I assure you I have done nothing to decrease the walkability by separating the grid. I knew from the beginning that would be perhaps the biggest disadvantage to doing so, so I made sure to place paths from every single dead end to the main road, as well as pedestrian/bike pathways up and over every single intersection that meets with an arterial (and in a ton of other places too). I probably have more ped/bike walkways than I do roads. Some average well over 5k pedestrian and hundreds of bike "trips" at any given time so they work well 🙂
My point about not having every block connect to the arterial is that the pathfinding AI is typically going to have 90% of the traffic coming from a certain direction take the same path into the grid anyway so you might as well plan for it ahead of time with some specific and purposeful design decisions to help mitigate issues (and I also see more cut-through, though I never said that was the issue here, just that it could be a potential factor)
Again, I only stated what has worked very successfully and very consistently for me in the past. The only red roads I really ever see are high-volume arterials and intersections with slow-turning corners. Most of it is even managed without any traffic signals. I also recognize that every city is unique and what works for one might not work so well for others. Doing it the way I do works very well if you have it set up right, but I agree it can be a disaster if you don't
Anyway Lee you make extremely good observations about the zoning and how being very thoughtful about zoning eliminates many issues before they can begin. Just how I like how a good well-planned road hierarchy help the overall flow feel natural without so many vehicles wandering through neighborhoods they have no business in
In the end there's no "one" fix, obviously. Ideally we're zoning thoughtfully, expanding logically by planning things out ahead of time to prevent future headaches, enabling and encouraging walking/biking, establishing robust public transport, etc...it all plays a part
thanks for the discussion all 🙂
lapis sierra
probably won't get better than this
loud wave
oh I *assure* you I have done nothing to decrease the walkability by separating ...
I didn’t catch the paths…what you’ve done (especially if you added crosswalks for the paths on the main roads) is a great example of filtered permeability, where motorized traffic gets funneled to roads designed for it and the other streets are very quiet and walkable. I think this is the best way to design (it’s very Dutch-style), but it’s difficult to teach to new players—so I try to keep things simpler. I definitely think you have good ideas here.
loud wave
probably won't get better than this
I think that roundabout is trouble. Having intersections so close…especially signalized or with left turns is trouble.
cerulean iris
only perhaps a more free-flowing interchange not requiring traffic lights, and/or something more free-flowing than a roundabout. I've come to personally hate roundabouts where high volume is needed
loud wave
only perhaps a more free-flowing interchange not requiring traffic lights, and/o...
Yes, I agree with here too. Roundabouts are touted far too frequently as a high volume solution when that’s not at all what they work for, while a traffic light would actually handle high volume much better.
lapis sierra
I've also added some paths
loud wave
probably won't get better than this
That is a whole lot better than it was. I recommend having your off-ramps be 2 lanes or 3 lanes…they’ll handle more traffic in less traffic light time.
loud wave
I've also added some paths
Paths are always good, but paths won’t help trucks at all…so you’re still gonna need to move them more efficiently if you want to reduce congestion. I’m not a perfectionist when it comes to congestion…this setup will work right now…it won’t handle much more traffic though.
lapis sierra
where should I put traffic lights and where stop signs?
also is it a good choice to have a 2+1 road here?
cerulean iris
if you did, i think it should be flipped the other way since your trucks are getting backed up getting off the highway, not getting on it. that said, it doesn't look like many are turning left onto the arterial (though some will probably want to, and cars too)
loud wave
also is it a good choice to have a 2+1 road here?
You want the two in the other direction.
loud wave
Try it without the roundabout. Don’t connect the first street, use the second or third one. Use a wider avenue leading up to the first intersection…if you have TMPE give it a dedicated left turn lane. Use a 6 lane road over the highway.
cerulean iris
it would be interesting to see if the traffic coming from the interchange towards the roundabout is mostly headed one direction (the industrial area) or if it spreads out more evenly...
If mostly one direction, you could (in addition to Lee's last suggestion) also consider an elevated bypass if you feel up to trying your hand at using the Vanilla Overpass Project assets to give the priority traffic easier access. just a thought, they can be useful sometimes
lapis sierra
it spreads out
cerulean iris
it destroyed everything
these problems can be very frustrating, eh?
is the cross-street at that new intersection just a two-lane road?
lapis sierra
I upgraded it to a 6 lane and nothing changed
cerulean iris
so you have 6 lanes going all four directions?
cerulean iris
timed traffic light?
lapis sierra
vanilla
cerulean iris
elevated ped pathway so there are no crosswalks?
lapis sierra
yup
cerulean iris
vanilla
ahhhh gotcha
do you see a lot of vehicles going straight, or are most turning one way or the other?
cerulean iris
i should go too lol. perhaps we can troubleshoot more another time and/or get more input from others
lapis sierra
perhaps.
loud wave
You could reconnect other parts of that grid and just ban left turns and through movements. You only need to knock congestion down a little bit. A few right turns out of that industrial area will really help prevent too much funneling to that traffic light.
Use 2-unit 3-lane or 4-lane roads to get into that industrial neighborhood, with at least 1 dedicated left turn lane…2 would be good if you use 4-lane roads in.
It’s incredible how much forcing everything to be right turns can do.
plush halo
here's the entire city so far
Your main problem with the traffic is a lack of connectivity across the highway. You need to add more connections between the two sides of the city to avoid funneling.
You might want to try adding a collector connection here:
You might also want to try implementing a one-way grid in that industrial area. It should help if you configure it appropriately.
Have you also considered adding highway access for trucks trying to access the other side of the industrial district? See the yellow highway ramps proposed in this example:
Don't really see a way you could fit a full interchange there, but it should alleviate some pressure from the parclo...
lapis sierra
Have you also considered adding highway access for trucks trying to access the o...
This highway segment is a custom bridge and it's way too high to build an interchange