Commute loop?

[Nielsen 10]

I see that people refer to this as a game breaking bug. I have never noticed the problem in my cities and how does it show, thus being game breaking? Curious about this.

  Edited June 8, 2012 by Nielsen  

[Tarkus 6,931]

The commuters, not remembering their point of origin, eventually end up back in the city they started and continue commuting, and the end result is that they end up getting double-counted. As you play each city tile involved in the loop, it basically multiplies over and over, and the result, in short, is that you get insane congestion and your sims have difficulty getting to jobs.

-Tarkus

[Mithrik 562]

Doesn't the NAM and other traffic fixes help reduce this bug's effect?

To what I have read, this bug is partly caused by the inefficent commute system of the game without these fixes, and while it cannot be completely removed, those are a huge plus to reduce it. I don't say it only from theory, by experience too. Since I started using the NAM, the commuter loop in my cities became non-existant (or no longer big enough to affect them), so I have easily gone over the 100000 inhabitants on a city without a single job zot on a developed region.

[A Nonny Moose 8,261]

It is a problem in the .exe where no definite destination is set for an out of town commute because the game can only see one city at a time. On arrival in a new city, the job hunt restarts, and if one is not found, a further migration occurs. Eventually you can get a loop back if no job is found. This is not preventable unless the program could page-in the destination cities. Beyond the ability of the operating system when this was written. They basically opened a can or worms and some of them are snakes.

The best test for this is overloaded neighbour connections with more commuters than there are Sims in the city. When you detect one of these, break the connection and rethink it.

A vast improvement in this game would be to load the entire region into virtual memory and page cities as needed. Could really slow things down, but if you have lots of RAM is might be possible.

  Edited June 6, 2012 by A Nonny Moose  

[I. Lostalim 588]

I see that people refer to this as a game breaking bug. I have never noticed the problem in my cities and how does it show, thus being game breaking? Curious about this.

I have never had that problem either.

[z1 566]

Doesn't the NAM and other traffic fixes help reduce this bug's effect?

No; as A Nonny Moose pointed out, the bug is embedded in the game's executable, and there's nothing we can do to fix it. In your case, the NAM traffic simulator may have changed your traffic routes to be more efficient in a way that removed the routing requirements for the bug in your cities. Conversely, there are cities where installing the NAM and creating more efficient routes leads to the arising of this bug. Most of the time, though, the NAM has no effect on this bug either way.

[Nielsen 10]

Thanks for the replies. I decided to try out the NAM even though it doesn't fix this bug and an off-topic question arises, What do these medium, ultra etc. settings mean and is it possible to change this setting after having configured it during install?

  Edited June 7, 2012 by Nielsen  

[z1 566]

These settings refer to the capacities of the SC4 networks. It's generally good to start off with the default setting of Medium. If you want to change your capacities later, you can do it via the Traffic Simulator Configuration Tool. This tool is automatically installed if you choose the "I want to build a custom simulator" option during NAM installation. Alternatively, you can always download it separately; it's part of the

[Nielsen 10]

These settings refer to the capacities of the SC4 networks. It's generally good to start off with the default setting of Medium. If you want to change your capacities later, you can do it via the Traffic Simulator Configuration Tool. This tool is automatically installed if you choose the "I want to build a custom simulator" option during NAM installation. Alternatively, you can always download it separately; it's part of the

I installed the configuration tool but it recommeds to start out with classic. Is medium really realistic as an initial setting? I made a region for NAM testing and congestion isn't much of an issue on the medium setting whereas congestion problems are looming on the classic setting.

  Edited June 8, 2012 by Nielsen  

[A Nonny Moose 8,261]

Classic put the NAM simulator into neutral. Medium provides a nice standard improvement to reduce abandonment due to commute. I run with it that way. There are also some extremes for special purposes. Try Park 'n' Ride for a real change. You will need lots of rail transport to get from home to work, short bus routes, and parking facilities.

[z1 566]

I installed the configuration tool but it recommeds to start out with classic.

It shouldn't; it was designed to start off with Medium. Classic was actually a rather late addition to the simulator, long after the other capacity levels; as its name implies, it was added to provide capacities comparable to those found in the original Maxis traffic simulator, but otherwise provide all the advantages of the NAM traffic simulator. For most urban situations, the capacities it provides are too low.

Where did you see a recommendation for Classic mode?

Classic put the NAM simulator into neutral.

For the reasons mentioned above, I would have to disagree. What constitutes a "neutral" mode really depends on the size of your city.

Medium provides a nice standard improvement to reduce abandonment due to commute.

Changing the simulator's capacity actually has no effect on abandonment due to commute time. (The one exception is if you use the Traffic Simulator Configuration Tool to reduce the maximum commute time by 98% or more.) Traffic congestion has various subtle effects, such as mayor rating, residential and commercial desirability, etc., but abandonment due to commute time is not among them.

Try Park 'n' Ride for a real change. You will need lots of rail transport to get from home to work, short bus routes, and parking facilities.

I just want to stress here that if you do this you will need lots of extra parking facilities (specifically near your mass transit stations); otherwise, you will drastically increase your abandonment due to commute time. The reason for this is that Sims will still choose to use their cars as much as before, but they're not allowed to drive directly to their destination. If they can't park somewhere and take mass transit (or walk, if the distance is short), they will be unable to get to work

[Traveller 28]

Is there some sure-fire way to tell if this is happening to me? I dont have the experience to tell, depsite all the time I sepend working on my region. I have my main city pop. 1.25 million and 2 adjacent tiles ~450k, and several smaller cities 30-50k range besides. If it was going on, id be hard pressed to tell. All my transit seems over-loaded despite offfering subways, rail, GLR, bus service, you name it. The city connections seem quite busy, and I am geting some 'Problem at this Avenue' messages and heavy traffic at the connections, but again, Id be hard pressed to tell even if it was happening.

[A Nonny Moose 8,261]

Is there some sure-fire way to tell if this is happening to me? I dont have the experience to tell, depsite all the time I sepend working on my region. I have my main city pop. 1.25 million and 2 adjacent tiles ~450k, and several smaller cities 30-50k range besides. If it was going on, id be hard pressed to tell. All my transit seems over-loaded despite offfering subways, rail, GLR, bus service, you name it. The city connections seem quite busy, and I am geting some 'Problem at this Avenue' messages and heavy traffic at the connections, but again, Id be hard pressed to tell even if it was happening.

I've always felt that if you have more traffic on a link than their are Sims in your population it is probably a loop and you should cut that link (after a save) to see if this is the case. You need to allow about six Sim-months for things to settle down. If you have a really big city, it could take longer. The pathfinder doesn't run continuously.

[Nielsen 10]

It shouldn't; it was designed to start off with Medium. Classic was actually a rather late addition to the simulator, long after the other capacity levels; as its name implies, it was added to provide capacities comparable to those found in the original Maxis traffic simulator, but otherwise provide all the advantages of the NAM traffic simulator. For most urban situations, the capacities it provides are too low.

Where did you see a recommendation for Classic mode?

Well, it was a recommendation for rural areas, hence I wrote "start out with" but I see why it could have been misunderstood. The TSCT welcome message says: "Generally, you would use classic for rural areas and towns...". However, the install does recommend medium or that is the one that has been pre-selected. But you say that classic is an improvement? Yesterday someone told me that classic is not an improvement at all as it simply reflects a simulation identical to an unmodded version of SC4. However, he might have referred to capacity levels but does classic still provide the improved pathfinding?

  Edited June 11, 2012 by Nielsen  

[Traveller 28]

I re-discovered the route-query tool! I was quite suprised to see that traffic levels are quite modest between my 3 large cities, no real problems there. The closest I come is 2 of my smaller towns. POP 64k and 35k respectively. Query says there is close to 30k in bus traffic and a few thousands cars combined, That was the lane from the 35k city. Into shows 5/6k. They are connected by and avenue and I get a lot of bus crashes needless to say heh. The other connectors to the large city to the west pop 420k is showing 65k! rail passengers! However, I should note town runs a rail line straight through to the east to another large city 150k+ it shows 56k passengers exiting the town along that route.

  Edited June 11, 2012 by Traveller  

[z1 566]

Is there some sure-fire way to tell if this is happening to me?

Well to start with, what A Nonny Moose said is quite true - if you have the amount of traffic he's talking about, you probably have a loop. It's traffic on these scales that can make this a game-breaking bug. But you can have a lot less traffic that that and still have a loop that damages your cities, though more subtly. You need to use the Traffic Volume Data View to see if you have heavily traveled routes that go from one border to another. Then you have to look at the adjoining cities and see where those routes go. If you keep doing this and end up where you started, then you've got a loop.

But you say that classic is an improvement? Yesterday someone told me that classic is not an improvement at all as it simply reflects a simulation identical to an unmodded version of SC4. However, he might have referred to capacity levels but does classic still provide the improved pathfinding?

All the different versions of the NAM traffic simulator are identical except for their network capacities. So yes, the Classic version has the perfect pathfinding like all the others, as well as the various other improvements that were made to the traffic simulator.

I re-discovered the route-query tool! I was quite suprised to see that traffic levels are quite modest between my 3 large cities, no real problems there. The closest I come is 2 of my smaller towns. POP 64k and 35k respectively. Query says there is close to 30k in bus traffic and a few thousands cars combined, That was the lane from the 35k city. Into shows 5/6k. They are connected by and avenue and I get a lot of bus crashes needless to say heh. The other connectors to the large city to the west pop 420k is showing 65k! rail passengers! However, I should note town runs a rail line straight through to the east to another large city 150k+ it shows 56k passengers exiting the town along that route.

From what you say, it doesn't sound like you have an eternal commuter loop. However, it does sound like your simulator capacity may be too low for your city. You might want to try raising it (unless you like the challenge of extremely congested traffic, which is why you're getting all those crashes). You can change your traffic simulator's capacities with the Traffic Simulator Configuration Tool. If you don't already have the Traffic Simulator Configuration Tool, you can download it as part of the

[Nielsen 10]

All the different versions of the NAM traffic simulator are identical except for their network capacities. So yes, the Classic version has the perfect pathfinding like all the others, as well as the various other improvements that were made to the traffic simulator.

Ok, thanks for making that clear.

This may not be related to commute loops but I'm not sure about that and since we're talking about the NAM, I thought it would appropriate to post it here. I noticed a couple of things which puzzle me. Please see the screenshots below and explain why the routes used for morning and evening commuting aren't the same. It's evident on the bypass roads highlighted by the red circles and notice that there is no traffic volume for the evening commute. As it can be seen, it clearly affects capacity levels within the city when certain roads are left untouched.

Morning:

Evening:

I use the NAM medium simulation and was also wondering why the road capacity numbers do not match those written in the TSCT. For example, see 100% (2000) in the screenshots above compared to the road capacity number of 4000 in the screenshot below. I know that streets, roads, highways have different capacities so does the in-game volume number reflect an average of these combined or how should I understand this?

  Edited June 12, 2012 by Nielsen  

[z1 566]

Please see the screenshots below and explain why the routes used for morning and evening commuting aren't the same.

The answer is simple - the traffic simulator calculates morning and evening commutes differently. For the morning commute, it tries to find the optimal route, which for the NAM traffic simulator means that it finds the fastest route. (The original Maxis traffic simulator also tried to find the fastest route, but it was tuned so poorly that it usually just found the shortest route in terms of distance.) For the evening commute, the simulator is programmed just to find any route that gets the Sim home from his or her job. This is often just the reverse of the morning commute, but not always. It's reasonable to assume that this difference in computations was implemented in order to save CPU time when computing the trip home.

I use the NAM medium simulation and was also wondering why the road capacity numbers do not match those written in the TSCT. For example, see 100% (2000) in the screenshots above compared to the road capacity number of 4000 in the screenshot below. I know that streets, roads, highways have different capacities so does the in-game volume number reflect an average of these combined or how should I understand this?

The Traffic Volume Data Views show the volume for a single commute period, while the network capacity (which is shown in the TSCT) is for the entire day, which encompasses both commute periods. For this reason, it's exactly twice the amount as shown in the Traffic Volume Data Views.

[Nielsen 10]

Thanks!

Another question arises, I also noticed that some of the morning commuters leave the city (upper right corner of the previous screenshot) but the connecting road leads nowhere, i.e. there is no city on the other side. Why is that?

[z1 566]

When there's no city on the other side, the connection goes to SimNation. SimNation has limited functionality, far less than a regular city, but allows things like certain connection types to be completed. You can't actually view SimNation, other than in the region view.

[Nielsen 10]

So Sims do not only commute to jobs but actually travel to an "artificial" place in the region?

[z1 566]

So Sims do not only commute to jobs but actually travel to an "artificial" place in the region?

You mean an artificial simulated place as opposed to a real simulated place? Well, sort of. SimNation is a little bit like a huge unincorporated area (it's everything that's not a city in the Region view), but without the details of the rest of the game. Remember that even when Sims cross from one city to another, the game doesn't know what their final destination is - simply that there is a job available for them. It's this lack of specificity that makes eternal commuter loops possible. However, these loops always go through cities; they never go through SimNation, as SimNation is never actually "played".

[A Nonny Moose 8,261]

I play on a regional basis, and you should maybe considering doing a little of this, to get rid of SimNation. Just open the city on the other end of the neighbour connection and put something there that will provide some jobs. A block of ID will do the trick, but you should consider spreading out of working on single city tiles. It doesn't take all that long to switch if your plugin suite is lean and mean.

[Nielsen 10]

You mean an artificial simulated place as opposed to a real simulated place? Well, sort of. SimNation is a little bit like a huge unincorporated area (it's everything that's not a city in the Region view), but without the details of the rest of the game. Remember that even when Sims cross from one city to another, the game doesn't know what their final destination is - simply that there is a job available for them. It's this lack of specificity that makes eternal commuter loops possible. However, these loops always go through cities; they never go through SimNation, as SimNation is never actually "played".

Yes, that is exactly what I meant and thanks for all the info, been a huge help!

I play on a regional basis, and you should maybe considering doing a little of this, to get rid of SimNation. Just open the city on the other end of the neighbour connection and put something there that will provide some jobs. A block of ID will do the trick, but you should consider spreading out of working on single city tiles. It doesn't take all that long to switch if your plugin suite is lean and mean.

I usually only create connecting roads if I plan to start a neighbouring city immediately. The thing is, I just recently got the NAM and for this I have created a test region where I try out different scenarios. I kind of try to get used to how the NAM changes the game for the better and therefore I do some things that I normally don't. This means that I notice things that I never really have paid much attention to such as traffic volumes fading into SimNation. Anyway, plugins shouldn't become much of an issue in terms of loading times when switching between cities. The only plugins I plan to use is the NAM, the IHT jobs fix, the opera hall fix and the space port fix. I prefer to keep the game as close to the orginal as possible while acknowledging the mods which address the most significant gamebreaking issues. I might add a few other fixes before I start a new region but it shouldn't make much of a difference as my laptop is quite powerful (despite running Vista ). Nonetheless, thanks for the advice.

  Edited June 13, 2012 by Nielsen  

[A Nonny Moose 8,261]

You should always test all new plugins. Saves a lot of grief if you get an incompatible one that doesn't blow up right away.