Possible (Maybe Not) Solution to Eternal Commuter Problem?

[Eusebio Ptolomeu 24]

Let me first adress the very important fact that I'm not a programmer and I don't know if this solution would be viable at all, so perharps someone with a deeper understanding of the game can correct me here.

We all know about the eternal commuter problem/loop in SC4 (otherwise, you can easily find about it here in Simtropolis). For some people, it's just a minor bug. To others like me, it's a headache. I've seen lots of ways to deal with this problem, ways which I highly recommend to anyone trying to solve it. I have a suggestion for a mod that, if feasible to make it, could solve or at least reduce this problem. The idea is based around SC4 path-finding algorithm, which prioritize the time of a trip over it's lenght. A Sim would favor a long route if it was faster than a short one, for example. So, with this in mind, my idea would be to simply penalize sims for switching over cities. In other words, the act of crossing the border alone should account for an added extra time to the route. This way, a sim would think twice before looking for a job in the next city. Now, I'm know that this idea would bring some problems:

 1- I don't even know if such modding is possible in SC4. I'm trying this suggestion because, after seeing what the NAM is capable of, perharps this idea is not that impossible. I don't know myself, so anyone with a better understanding of the game can answer here.

 2- An amazing thing about SimCity 4 is it's regional playing, where a Sim can live in a city and work in the next one. This mod should no prevent this from happening, it should only prioritize work within the same city

3- Is it possible for the simulation to separate sims of the city from those ones which came from the border? If so, perharps we could code a mod that prevents these sims which arise from the connection to ever consider another connection too. This would limit Sims to, at best, look for jobs in the next city, and never beyond.

 

[CorinaMarie 29,771]

Hiya, @Eusebio Ptolomeu. Welcome to Simtropolis!

I like the concept of some way to limit those eternal commuters via modding. However, it doesn't appear possible. The data that the game code reads and uses for travel is tucked away in Exemplar 0xc9133286 which is the Traffic Simulator. Several variables interact in how the game determines trip length. I'll post an image of the relevant exemplar so you can see what there is to work with:

Along with the driving speeds for each type of travel on each type of network (not highlighted above) there are the Pathfinding Heuristic, the Network Traffic Capacity, the Congestion vs Speed, and the Commute trip max time variables.

For any given Sim the game first looks around to see if there is an available job for them in the current city tile. If not, then it checks if there are any jobs in a neighboring tile.  If there is a job available in the current tile then it starts looking for ways to get the Sim there within the amount of raw time allowed (Commute trip max time). The Pathfinding Heuristic number is the factor for the depth of the branching search it makes to see if that is possible within the allowed time. The search takes into account the travel speed for each network (and combinations of network paths), factors in the Congestion affect on said overall speed based on the percent of the capacity used, and then decides if that will work before trip time exceeds the max allowed.

On the other hand, if the game decides the Sim should work outside of the current city tile all the processes it does are handled in the executable code and there are no variables modders can change to affect that.

So, unless I've made some mistakes in my understanding of all this, it's just not something we can do.

[Eusebio Ptolomeu 24]

Thanks for your answer @CorinaMarie! So, it looks like, since the simulation aspects of the Sim working in another city is handled by parameters we can't change, there's not much we can do. I just thought that this was possible since the NAM team was able to change the pathfinding simulation of the game. How did they do that?

[CorinaMarie 29,771]

4 minutes ago, Eusebio Ptolomeu said:

I just thought that this was possible since the NAM team was able to change the pathfinding simulation of the game. How did they do that?

I'll let the experts explain: Tutorial:Understanding the Traffic Simulator

Also, to clarify a point: When the game decides there is no job for the Sim in the current tile it looks to see if there are any jobs in neighboring ones. At this point it doesn't even care if those jobs are already filled or even it it matches the Sim's wealth level. It just tosses them out the door and only then checks if they could actually find a job there. If that answer comes up No then it starts looking for other tiles the Sim could travel to. The only thing it doesn't allow is the Sim to travel back into the same tile it just left via the same network.

Also, this topic prolly would be better off in the modding forums so I'll whisk it away to over there.

[Eusebio Ptolomeu 24]

Thanks, I did not see there was a specific forum for modding of sc4. Sorry for the problems Also, I'm going to take a look at this text you linked, perharps it might show a way to "trick" the game to solve this problem. On a more playing aspect, how do people deal with this? Not in the sense of avoiding it only, but do this problem really and greatelly affect the simulation, or is it a just minor bug that we can simply forget?

[11241036 5,105]

I think that theoretically there is a solution to this problem: With the same mechanics that people use to create transit-enabled traffic stations, it is possible to create transit-enabled lots looking exactly like the networks they are being plopped on - but with the side effects you mentioned: One could either make sure that it takes the sims really long to get past this lot (this is done by raising the value at the Transit Switch Entry Cost property to a high value); furthermore, it's entirely possible to block traffic from passing it. A good while ago, I released a set off traffic blockers (link below); I'm thinking of improving the lotting, but they work (albeit they only block one type of traffic, not all traffic altogether).

 

[Eusebio Ptolomeu 24]

Thanks for this, I'm going to download it and see what happens!

[Eusebio Ptolomeu 24]

2 hours ago, 11241036 said:

I think that theoretically there is a solution to this problem: With the same mechanics that people use to create transit-enabled traffic stations, it is possible to create transit-enabled lots looking exactly like the networks they are being plopped on - but with the side effects you mentioned: One could either make sure that it takes the sims really long to get past this lot (this is done by raising the value at the Transit Switch Entry Cost property to a high value); furthermore, it's entirely possible to block traffic from passing it. A good while ago, I released a set off traffic blockers (link below); I'm thinking of improving the lotting, but they work (albeit they only block one type of traffic, not all traffic altogether).

 

Well, this is already a mod that everybody looking for a aesthetically pleasing city needs to have, whithout the need to abolish road connections entirely. However, there are 2 ideas that I had and I wonder if they could possibly work:

1- The first, involving your mod, is to, instead of blocking cars or bus in it's entirety, just give that huge penalty in the commute time, therefore forcing the simulation to favor other paths, if possible
2- The second, after reading @CorinaMarie link, would be to aks the simulation to favor any job within the tile over jobs in other cities, no matter how far this job might be (the Commute Trip Max Time parameter, I think). For example, a sim living in the eastern edge of a huge city tile would rather work in a factory in the western edge than to work in the next city (even if, in a regional "human" sense of thinking, it would be far closer, like literally next to his/her home, but separated by the borders). This should help with the problem, because as soon as the simulation finds a job within the tile, it will choose this job instead of looking for one in the other tile. Entirely residential/comercial/industrial cities would still be possible, technically (the simulation won't find no job in the residential city, so it really has no choic but to send the sim to the next one). The eternal commuter problem would still be possible if within the tiles forming the loops, the simulation cannot find a job (say, for example, a loop of cities containing ONLY residential areas). It's still possible to have this problem, but modding the game this way, at least we discard the "would it be better to work in the next city?" thinking, reducing the chances of it appearing.

In a final note, is there a way to move this thread to the modding section? There is really where this kind of thread should be
 

[matias93 7,535]

If I understood clearly, the best method to do so would be to use traffic delayer lots at all neighbourhood connections, to make the traffic simulator to prefer local routes over regional ones. That way, it wouldn't be a general fix (apparently that's not doable), but something that the player would need to establish on an one-to-one basis, on each tile and connection; it would be much slower, but also much more flexible.

[Eusebio Ptolomeu 24]

5 hours ago, matias93 said:

If I understood clearly, the best method to do so would be to use traffic delayer lots at all neighbourhood connections, to make the traffic simulator to prefer local routes over regional ones. That way, it wouldn't be a general fix (apparently that's not doable), but something that the player would need to establish on an one-to-one basis, on each tile and connection; it would be much slower, but also much more flexible.

I believe this would work too, but what kind of lot works like a delayer? @11241036created a good mod, however it looks like it blocks entirely a kind of traffic (at least this is how it workd for me). I know toll booths works like that, but for some reason, their delay doesn't seem to be enought to change the simulation's mind (at least it wasn't when I tried it).

[CorinaMarie 29,771]

12 hours ago, Eusebio Ptolomeu said:

I believe this would work too, but what kind of lot works like a delayer?

Based on @11241036's post above, it sounds like you'd have to make it yourself.

From one lot in his Traffic Blocker set, here's the relevant Transit Switch Entry Cost property which he mentions would need a high value:

Ofc, using this particular example lot the property which blocks certain traffic would need to be set back to not do that part.

[CorinaMarie 29,771]

Me again.

 

6 hours ago, Eusebio Ptolomeu said:

I know toll booths works like that, but for some reason, their delay doesn't seem to be enought to change the simulation's mind (at least it wasn't when I tried it).

I altered the Maxis Avenue Toll Booth so you can test various Transit Switch Entry Costs. The Maxis default for the TSEC is 0.2 and the capacity is 3,000. For all of the included files I've upped the capacity to 50,000. We don't want them shutting down for the day should the usage exceed 400(ish)%. Then for each file I doubled the TSEC value so you can test them and see if any do what you are seeking by making it more and more undesirable for Sims to want to use the avenue route where you plop one.

All the files are included and I've named it so if you use the Windows default unzip suggestion for extract all it'll create a folder named z____AvenueTollBoothTests which will hopefully make it load later than any other plugins including z___NAM. Be sure to then move out all but one .dat file when conducting your tests. Then swap in a different one for the next test. (Again, be sure to only have one of them anywhere in Plugins for each test.)

For each test, bulldoze the toll booth before exiting the game. Then do the swap in Plugins and re-plop the new one once back in your city.

z____AvenueTollBoothTests.zip

[matias93 7,535]

This looks like a releaseable mod, don't you think?

As it restricts sims from crossing the border, I would recommend naming it "Make the City Tile Great Again"

[Eusebio Ptolomeu 24]

1 hour ago, CorinaMarie said:

Based on @11241036's post above, it sounds like you'd have to make it yourself.

From one lot in his Traffic Blocker set, here's the relevant Transit Switch Entry Cost property which he mentions would need a high value:

Ofc, using this particular example lot the property which blocks certain traffic would need to be set back to not do that part.

What is the name of this program where you can alter such values?

[CorinaMarie 29,771]

3 minutes ago, Eusebio Ptolomeu said:

What is the name of this program where you can alter such values?

That'll be iLive - Reader 0.9.3 and there's also the Tutorial:The Reader Beginners Guide to help get started with it.

[Eusebio Ptolomeu 24]

So I did some experiments, and this is what I've found

I tried tweaking some parameter with the Traffic Configurator Tool. Namely, I changed the Maximum Commute Time to the maximum value allowed, of 999. I did this because, if I understood correctly, this way any possible job within the tile would be considered "close", while any job in other cities would be considered far from home. Basically, I was hoping that, with this, I could implement that idea to force the simulation to choose always a job in the same city, if possible. However, the eternal commuter problem still persists in my cities. I let the simulation run for about 20 years to see if it made any difference. There were lots of upgrades to the traffic in the rest of the town, but the road afflicted by the loop remains the same. I checked the path sims were following in this road, just to be sure: indeed, the huge majority of sims coming from city B(about 7800 incoming sims) uses this road just to get to city C. I expanded industrial and commercial zones, still withouth effect.
However, I noticed something funny: in city A (the city I am playing) it says that there are about 7800 sims crossing it's borders with city C. However, once I load city C and check the same connection, the number is different, even after letting the simulation run for years. Same thing happens between any other connection in my region, they don't match between one city and the other. Is this a normal behaviour? Perharps NAM isn't working properly in my game, I heard that the Collossus Addon, which I've downloaded too, overwrite NAM files. If that is the case, is there a proper way to uninstall CAM, like the NAM uninstaller, so I can check it?

[CorinaMarie 29,771]

26 minutes ago, Eusebio Ptolomeu said:

I tried tweaking some parameter with the Traffic Configurator Tool. Namely, I changed the Maximum Commute Time to the maximum value allowed, of 999.

From the TSCT User's Guide :  "Raising this value beyond 600 does not seem to have any effect at all." so it's prolly not surprising it made little difference.

 

26 minutes ago, Eusebio Ptolomeu said:

Is this a normal behaviour?

Yep. It's perfectly normal within the scope of the game. What's happening is that Sims leaving a city seeking jobs elsewhere are all those who feel they might find a job by crossing the border. However, on the other side it counts only those who might find a job in the incoming tile or via another route out of said tile.

For example Sims in this city believe there are oodles of jobs available via the neighbor connection:

Yet on the other side they can only find 4 jobs:

I haven't yet convinced them to form the eternal loop. It might be I have made the loop too large distance-wise.

 

26 minutes ago, Eusebio Ptolomeu said:

I heard that the Collossus Addon, which I've downloaded too, overwrite NAM files. If that is the case, is there a proper way to uninstall CAM, like the NAM uninstaller, so I can check it?

My (very) limited knowledge of this is that there is an option when installing CAM which relates to the Traffic Simulator and might have an option to toggle on or off to install that part. Since I don't use CAM we'll have to wait for the experts to comment on this.

 

26 minutes ago, Eusebio Ptolomeu said:

So I did some experiments,

Any luck with the Avenue Toll Booths with the altered TSEC variables?

[jeffryfisher 2,176]

1 hour ago, CorinaMarie said:

there is an option when installing CAM which relates to the Traffic Simulator and might have an option to toggle on or off

In CAM 2.1, the CAM traffic simulator is off by default and text discourages its use.

There's also an optional traffic sim in one of PEG's mods (was it MTP? I can't recall). If you have PEG stuff, be sure to skip that one also. Otherwise you could be overriding the NAM.

IIRC, NAM already boosts max commute to make all in-city jobs closer than any over-the-border jobs. Just make sure that jobs are connected to housing for BOTH morning and evening commutes. One-way streets and some asymmetric freeway ramps can block flow in one direction, preventing sims from taking jobs.

The best way to reduce commute circles is to avoid building short-circuit loops of connections around city corners. Can you post a picture of a traffic heat-map of the shortest leg of your current commuter loop? Maybe we can suggest some alternate routes.

[rsc204 21,836]

The old CAM Traffic simulator should never be used if you have the NAM installed, likewise the one that's an optional part of the SPAM mod by Pegasus. You can only have one and the CAM one is simply outdated, although many of it's changes made their way into the NAM. The SPAM one simply works very differently and may cause big problems when using the NAM.

I believe the conundrum here is that trying to convince sims to remain within a city to prevent eternal commuter loops, is essentially cutting your nose off to spite your face. Finding a set of values which will balance sims not wanting to leave a city, but still making them do so when they must is going to get messy. The game mechanics just don't really work this way and whilst you may find the sweet spot between them, just know it's going to take a lot of trial and error and testing. My initial thoughts are that you'll just end up with No Job zots where an imbalance between demand regionally existing, but sims inflexibility to get to jobs as they need too, will have caused growth of things in the wrong places.

The crux of this problem is that once a sim crosses a border, the simulator knows next to nothing about them. Because the strain upon the simulation of commuters being calculated region-wide, would bring down a modern high-end PC. Frankly, you can easily take a top end CPU from today and SC4 will eat it alive eventually, OK not helped we can't use more than one core too. Maxis knew this and had to compromise somewhere, so the system works thus. Your demands are regional, so a building will grow in a city, because demand exists for it, but that doesn't mean a sim will be able to get either to/from work at this location. Only demand and the desirability factors dictate what grows and when. With some micro-management this can be controlled somewhat. Yes for the most part, sims who work in the same city as they live, will have short commutes whereas all sims that leave a city, will have a long commute. But this isn't as important as you might think with the modern NAM simulator, which pretty much gives a sim more time than they should reasonably need, to find a job. But if a sim leaves it's home city for work, the only time factor the game knows about, is how long it took to reach the border. The simulator won't know what's on the other side, only that there are jobs in that direction. In fact, so far as we can determine, it can't even know if a job for a particular sim exists anywhere beyond that crossing point. Yet, the sims will travel there anyway, if there is the slightest chance of finding work. Because the time calculation only factors getting to the border, especially where sims live near neighbour connections, they will often see this as the fastest route to a job, even if the reality is that it's not.

Avoiding placing residential too near such crossings can help, slowing down such networks may help too. Similarly, placing jobs within easy reach of the border will help persuade more sims to take one rather than continue onwards, assuming the jobs are right for them. Keeping such crossings away from corners is key to avoid loops, because when in the new city, if exiting again is quicker than moving towards the jobs, that's what sims will do. In fact, all sims at this point, where the appropriate job type doesn't exist, will simply look to exit the city in search of one elsewhere. Generally speaking, they won't move back to the source city (the one they just left), but you can hopefully see how just three such connected cities, could quite easily end up with sims on a road to nowhere. The problem with slowing them down, is that there is a real chance you just end up with sims who decide they can't make the border quickly enough. The equivalent of simply removing the border crossing in effect.

In-short the real problem here is that the game knows so little about commuters, when crossing such borders, that it leads to an inherent problem. Even if we could tweak the code somehow to fix this, you'd then have to calculate commutes for the entire region's population/distance for the simulator to work. This simply would result in at best, many minutes of waiting every time the game tried to run the traffic simulator, by far and away already the most resource-intensive operation of the game. Most likely the game would simply CTD or take forever to come back with results. The bigger the region, the more sims/jobs, the worse things would get, because such calculations are exponential. In short, it's nothing short of a re-write of the fundamental game code to fix and it would need to be either bloody clever or hideously compromised to work.

Ultimately, the commuter loop problem gets worse as your population grows. Back in 2003, the sorts of populations we have today were frankly implausible due to hardware constraints. But as we get faster, more powerful PCs, it has allowed very large regions and populations to be a thing. This in turn exacerbates the problem of eternal commuters, even using active strategies to minimise the problem. I think it's why Maxis would have thought this an acceptable compromise, because up to a certain point (population), the issue is marginal for most players. So, thinking laterally, there is a much easier solution here, albeit one that may not be popular. Why not simply have less sims in your region? Think about it, one region could have 20 million sims, but you could build an identical one, only with say 1 million sims. The only difference being, altering the values of residents/jobs to reduce them to 1/20th of their usual values. What in real terms have you lost in the process? I never get this, but people are obsessed with numbers, but it's the cities look and feel that really matters. However, with 1/20th of the number of sims to deal with, the traffic simulator can breathe far more easily and whilst the eternal commuter issue would still be there, it's effects would be much less pronounced. Downsides?, well the #1 issue is that you'd need to mod every building you use to alter the values. It's also important to ensure these are kept balanced to avoid messing with the eco-system of the game. Otherwise, the only other one I can think of, it's that little meaningless number for population being smaller. Perhaps too, you might want some sort of backwards-CAM mod, to help bring the rest of the game into line with the smaller populations. I guess it's a lot of work in the end, but it's a thought.

[Eusebio Ptolomeu 24]

On 13/07/2018 at 12:33 PM, CorinaMarie said:

Me again.

 

I altered the Maxis Avenue Toll Booth so you can test various Transit Switch Entry Costs. The Maxis default for the TSEC is 0.2 and the capacity is 3,000. For all of the included files I've upped the capacity to 50,000. We don't want them shutting down for the day should the usage exceed 400(ish)%. Then for each file I doubled the TSEC value so you can test them and see if any do what you are seeking by making it more and more undesirable for Sims to want to use the avenue route where you plop one.

All the files are included and I've named it so if you use the Windows default unzip suggestion for extract all it'll create a folder named z____AvenueTollBoothTests which will hopefully make it load later than any other plugins including z___NAM. Be sure to then move out all but one .dat file when conducting your tests. Then swap in a different one for the next test. (Again, be sure to only have one of them anywhere in Plugins for each test.)

For each test, bulldoze the toll booth before exiting the game. Then do the swap in Plugins and re-plop the new one once back in your city.

z____AvenueTollBoothTests.zip

I finally tried these toll booths, but they are not making much of a difference, even the 128x one. How do you guys deal with this kind of problem? Do you just forget that it exists and play the rest of the game, or do you actively try to fix it somehow? If I let this problem untouched, what kind of real effects will it have in my city, if any?

[CorinaMarie 29,771]

3 hours ago, Eusebio Ptolomeu said:

I finally tried these toll booths, but they are not making much of a difference, even the 128x one.

Ok. With something that's never been researched before how about trying some that are much more extreme? Included this time are 1,024x, 4,096x, 16,384x, and 65,536x. If sixty-five thousand times higher than the Maxis default doesn't make some noticeable difference I'd be willing to say this method isn't viable.

z____AvenueTollBoothTSEC-1024-65k.zip

 

3 hours ago, Eusebio Ptolomeu said:

How do you guys deal with this kind of problem?

With @jeffryfisher's oft used descriptive word: Build your regional transportation map using a dendrite structure. In other words make it branching such that the eternal loop is not possible. On the other hand, @A Nonny Moose was quite fond of saying you should just slap tolls booths on the loops and collect all the extra income if you weren't going to prevent the loop itself.

Another thing to keep in mind with this discussion is the Ferries can be a major source of an eternal loop and they only need to be two legs of the loop. Their speed from one ferry dock to the next is infinitely fast because Maxis didn't finish them and there is no option to add speeds for them.

[Eusebio Ptolomeu 24]

8 hours ago, CorinaMarie said:

Ok. With something that's never been researched before how about trying some that are much more extreme? Included this time are 1,024x, 4,096x, 16,384x, and 65,536x. If sixty-five thousand times higher than the Maxis default doesn't make some noticeable difference I'd be willing to say this method isn't viable.

z____AvenueTollBoothTSEC-1024-65k.zip

 

With @jeffryfisher's oft used descriptive word: Build your regional transportation map using a dendrite structure. In other words make it branching such that the eternal loop is not possible. On the other hand, @A Nonny Moose was quite fond of saying you should just slap tolls booths on the loops and collect all the extra income if you weren't going to prevent the loop itself.

Another thing to keep in mind with this discussion is the Ferries can be a major source of an eternal loop and they only need to be two legs of the loop. Their speed from one ferry dock to the next is infinitely fast because Maxis didn't finish them and there is no option to add speeds for them.

I'll try some of these higher numbers, but I'm starting to wonder if there is something wrong with my game, because the connectios between city A, B, C and D follows this dendritic pattern. City D, being for the moment, the "end" of the branch only has connections with city C, and indeed problems disappeared once I've done this. However, cities B and C have 2 connections, and they suffer the loop. It looks like my game isn't taking into account the fact that I bulldozed the loop A->D (there was such a loop, but I severed A-D connections). I tried to let each of the four cities to simulate for about 10 years, to make sure each one would have an "updated" view of the current no-loop condition, but the problem persists in the middle cities (and bizarrely enough, this does mean that more commuters are coming from city A to city B when played on city B, than when played on city A, like they were being generated (kind of the opposite version of that scenario I asked about). Given this, and the fact that different toll booths didn't seem to make any difference, I'm wondering if the NAM traffic simulator is actually working in my game. If my game is still running the old Maxis simulator, which only takes distance into account, then this behaviour would be explained

[CorinaMarie 29,771]

2 hours ago, Eusebio Ptolomeu said:

... more commuters are coming from city A to city B when played on city B, than when played on city A, ...

Let's say both city A and city B have 5,000 total jobs available throughout each of their respective tiles. Then in one city we have 1,000 Sims close to a border and they  cross over believing they will find work in the adjacent tile. That's all fine. They are paying their taxes and their homes are not dilapidating. But, then you jump to that adjacent tile and the transportation network only allows them to reach 100 jobs. That side will show 100 incoming while the other side shows 1,000 outgoing. I'm almost certain this isn't the definition of eternal commuters.

[jeffryfisher 2,176]

12 hours ago, CorinaMarie said:

Ferries can be a major source of an eternal loop and they only need to be two legs of the loop. Their speed from one ferry dock to the next is infinitely fast because Maxis didn't finish them and there is no option to add speeds for them.

However, the ferry terminals themselves have a transit-switch entry cost that can be adjusted. It's once on the water that sims have super-conductivity. I suppose they could loop then if your water has a loop in it. Ferry routing is very mysterious.

@Eusebio Ptolomeu BTW, It would be helpful if we could see a traffic heat picture of at least part (where "the problem persists") of the problematic transit loop.

[CorinaMarie 29,771]

Let's go ahead and clarify what eternal commuters are with pics from a real game.

Here's my region set up specifically made to cause them to happen:

 

Overview of City A:

 

Development in City A: The upper left corner is a balanced economy with just the right number of residents for the amount of jobs offered by farms, dirty industry, and a few commercials.

 

Here's the start of a loop in City A before adding the residential in this area:

 

In City B we have the loop with almost all jobs inaccessible on those farms:

 

City C has no jobs accessible from the avenue passing thru:

 

City D is the mirror image layout of City B with almost all jobs unavailable from the commuter loop:

 

Now let's see what happens once we've run and saved these cities in sequence and peek back in A:

 

And in B:

 

In C:

 

D:

 

And back to A. (Running and saving each tile as we go, btw.)

 

Round 2 in B:

 

Round 2 in C:

 

Round 2 in D:

 

And finally let's check a third time in A:

 

What this gives us is a stable base from which we could check those various Transit Switch Entry Costs of the modded Toll Booths. We have isolated all other variables of city design and layout.  And we have a true eternal commuter loop.

I'll attach my region so you can use it for a test should you so desire.

Eternal.zip

 

[Kloudkicker 4,561]

I am trying to understand the idea of the external commuter bug. In doing so, I found this relevant info from the Prima guide on trips and routes and thought I'd share it.

NOTE: All the info below is directly from SimCity 4 Rush Hour Prima Official eGuide  Link is for online viewing and has multiple free download options, like PDF.

_________________________________________________________________________________________________________________________________________________________________

WHAT IS A TRIP?

"A trip is a journey originating in one zone type and going to a particular destination. Where trips go is a function of where they originate:

• Residential: Jobs in Commercial and Industrial zones and in transportation, utility, and civic buildings

• Commercial: No trips (though should have easy access to Airport)

• Industrial: Freight trips to Connections (to SimNation), neighbor cities, Seaports

What a trip means also arises out of its source zone:

• Residential: Commute to the closest open job of the same wealth level

• Industrial: Freight shipment to the closest connection or Seaport"  [page 246]

TRIPS TO NEIGHBOR CONNECTIONS

"If there are Neighbor Connections via appropriate network types in your city, these can be used to complete a trip. For Residential trips, if you have a Neighbor Connection to a city (not SimNation), and it’s the closest destination, Sims will take jobs in the neighboring city. How long this trip takes depends on whether you’ve played that city since making the connection. If you open it, the simulator knows what jobs are available and how far they are from the connection; this known distance is added to the trip time to the connection for the total trip time. If you haven’t played the neighboring city, a large presumed trip time is added instead. When setting up Neighbor Connections, enter the other city and link your connections to job zones. Your commuters will thank you."  [page 252]

TRIP CONSEQUENCES

"When you add together the factors in trip time, you get the total time it takes the Sim to make his or her trip. How long that is makes a difference. A trip time of 2.5 hours is high, and your Sims will not take a trip that’s longer (raising the no job zot). The commute time for their tract will show as high and the tract’s desirability will take a hit. Likewise, your Mayor Rating on that tract will suffer. If a Sim is unable to find the destination, a no-job zot declares his or her intention to abandon in six months unless you fix the problem. You might also see the no-road-connection zot to indicate that there’s no valid network to get where the Sim wants to go. When these pop up, add more mass transit or new Roads or convert clogged Streets to higher capacity Roads." [pages 252 and 253]

WORKING IN NEIGHBOR CITIES

"... Residential Sims use Neighbor Connections to real cities to complete job trips. If the connected city hasn’t been visited since the connection was established or the connection isn’t linked to any jobs, the active city must estimate how far the job is from the connection on the inactive city side. This estimate is always punitively high. You must enter the other city after you establish the connection. Link the connection to the main Road network. When you exit this city, the simulator remembers the average commute time and adds it to trips exiting from the first city." [page 313]

CHANGES TO THE FUNDAMENTAL COMMUTING MODEL

"Before we get into the myriad transportation changes, there are some adjustments “under the hood” that alter the way you manage and understand SimCity transportation. In SimCity 4, Sims didn’t have static jobs they traveled to day after day, month after month. As described in Chapter 19, with each cycle the simulator would take each Residential building and find the closest open job to it. If the trip between home and job could be made in under 2.5 hours, this was considered a completed trip and thus the illusion exists that a Sim living in that house is driving to a job somewhere. With the next cycle, the simulator did this again, finding an entirely different job from the one during the prior cycle. All previous versions of SimCity have used some variation of this basic formula."

"With Rush Hour, however, fiction has come closer to reality. Here’s the difference: The simulator remembers from month to month what jobs it finds for each Residential structure and holds onto them until something changes. In other words, the Sims hold their jobs until something forces them to find another. Quite a bit more like life, no?"  [page 378]

ROUTE PLANNING

"Before departing, a Sim plans a trip to the closest possible (as the crow files) destination. If, while searching for a route to the closest destination, the Sim finds another destination along the way to the chosen one, he'll select that one instead (although it is linearly farther away from his starting point). Trips are planned in advance, so there’s no backtracking when a trip encounters potholes or excessive congestion." [page 247]

REROUTES AND JOB CHANGES

"Every four months or so (it can be longer for larger cities and sooner for smaller ones), the traffic simulator recalculates the route from a Residential structure to the existing job. If it finds a faster way (due to reductions in volume or availability of new routes or mass transit), the simulator will keep the Sim in the same job but take the new faster route. Sims now keep their specific jobs over the long term. This means you can see how and where they travel to work. If, however, it can’t complete the trip to that job in time or some other factor has made it impossible for the trip to be ted in under 2.5 hours, a new job is selected that will persist until at least the next recalculation. Other than increased commute time, what else could cause a change in job? A change in desirability at the workplace location could cause the number of jobs to drop. In this case, all Residential routes to the job site are recalculated, with some Sims having to look for work elsewhere. If a worker ousted by this process can’t complete a trip to any another job, he or she becomes unemployed and the no-job zot appears above that Sim’s home. Think of this as downsizing, SimCity style."  [pages 378 and 379]

RAMIFICATIONS

"The ramifications of this new system are profound. First, it makes it possible to observe the commute between Residential and Commercial/Industrial zones. This helps to diagnose traffic problems and makes possible the new Route Query tool. Second, it allows the simulator to accurately depict traffic volume on your city’s streets. What you see as congestion on the streets directly reflects the congestion, flow, and volume shown in the Traffic Data View— you can diagnose most of your city’s traffic problems without ever consulting the Data View. This is a sample of the things possible under this new transportation system."  [page 379]

(new)ROAD AND JOB ACCESS

"As discussed previously, every lot must have access to a Road or Street before it can be developed. Residential Sims have an additional requirement, they must be able to use those Roads to get to a job. This means two things:

• The Road must connect to at least one Commercial or Industrial zone.

• The Road must connect to available jobs. This means that the Sim must be able to find a job within a tolerable distance traveling from the selected tract. If there are no open jobs, the tract will be passed by."  [page 118]

(new)LONG COMMUTE (TO I OR C)

"Residents are concerned with the length of their commutes (known in technical jargon as “trip length”). Commutes are, by definition, from Residential zones to either Industrial or Commercial zones—ordinary Sims driving to work.

If a Sim’s route to work is too long because of distance or traffic, he or she will become so frustrated that he or she moves out of your city (see Chapter 19). Short of that, the commute time and Sims’ levels of frustration with their commutes affect the desirability of their tracts of land.

The effect of commute length can be positive if it’s short to medium, but it becomes more negative as time in the car increases. All Residential wealth levels view commute time equally."  [page 103]

  Edited January 20, 2021 by Kloudkicker  
Added more info (new)

[CorinaMarie 29,771]

Eternal commuters are not restricted to just the 3 or 4 nearby boundaries crossing scenario we all know.

I've been playing in Timbuktu Too and I have a loop that spans 22 city tiles.

We start here in Larger Town where 34,752 Sims hop on a train and go a wandering in search of the jobs they believe are out there for them somewhere:

 

They follow this path:

 

The 16,160 who have not found a job along the route enter into this city tile from the southwest:

 

And in this same tile, those 16k are part of the count for the outbound journey of the 33,739 which are coming in from the east and heading out north:

 

Adding a few from this local town and the traffic at that eastern boundary is now up to 51,104:

^ Whereas the fist time thru the journey it was just the 34k coming in.

 

In the next tile heading back towards the start we now have the combined incoming and outgoing Sims of 53,075:

 

So, just remember that it's not only the tight little intersections of a few city tiles that can allow this to happen.

[Kloudkicker 4,561]

9 minutes ago, CorinaMarie said:

Eternal commuters are not restricted to just the 3 or 4 nearby boundaries crossing scenario we all know.

What is the commute time for that city were they return to?

Is there no jobs for them to find?

[Propfam 2,292]

12 minutes ago, CorinaMarie said:

Wow, such developed Timbuktu Too region. I'm only have one fifth of yours.

[CorinaMarie 29,771]

3 minutes ago, Kloudkicker said:

What is the commute time for that city were they return to?

A wee bit over an hour:

^ But, it's not really a relevant question as it only matters for the city tile they start in.

 

4 minutes ago, Kloudkicker said:

Is there no jobs for them to find?

Of the 34,752 who started the journey, 18,592 did find work along the way. The other 16,160 are still searching and, unfortunately for them, they are heading back to where they came from.