NAM Traffic Simulator Development and Theory

[redraider147]

so noticed a massive difference (possibly a bug?) between the alpha release I was using and the beta i just started using.. It seems that the congestion on all my roads and streets and avenues etc, is much higher, while the volume is now much lower. also, it seems that my sims do not want to drive to work any more. My mass transit is ridiculously high...and the people who are taking it are the wealthy sims. the poor sims are driving. this seems to go against the natural build of RL and the game. I am wondering as to what might be causing this.

A side note, the abandonment problems we thought might be related to a conflict between the Alpha Release the CAM have virtually disappeared. and while my congestion is much higher while volume is lower, commute times are down. also it appears that my work on the express tracks with elrail and subway and GLR no longer works as the sims tend to overload the local trains even though they are going well down the line and actually getting off at an express stop. i guess it seems that the sims do not like the long rides without stops on the elrail/subway. i'll keep researching this and see if anything changes it.

[z]

It sound to me like you've installed the Park and Ride version by mistake.  Does your simulator file contain "_ZP_" in its name?  That's the Park and Ride version.  You want to make sure that your version just contains "_Z_" in its name.

Otherwise this does not sound like Simulator Z at all.  I would first want to rule out the hidden presence of another simulator.  The best way to do this is to remove Simulator Z from your Plugins directory and run the game for a while.  If things don't change radically within a few years, then you've got another simulator overriding Simulator Z and you've got to find it.

Otherwise, we'll have to dig deeper.  I'd start by asking you to tell me the name of the simulator file you installed.

[redraider147]

the only simulator i've been running for quite some time is the alpha of z. and the ZP is not in the file. i'm not sure...maybe still conflicting with the CAM, but in a different way?

[z]

I don't think so.  What is the name of the current simulator file you're using?

[redraider147]

NetworkAddonMod_Traffic_Plugin_Z_High.dat and NetworkAddonMod_Volume_Data_View_Z_High.dat

Formerly with the alpha release, i was using Tarkus' Congestion View...would that have anything to do with this? Currently I do not have a congestion view mod installed unless there is one now included with z. which would result in me using the maxis congestion view and could be distorting my findings. I still am not sure about why my poor sims are driving and my wealthy sims are taking mass transit...

[z]

Formerly with the alpha release, i was using Tarkus' Congestion View...would that have anything to do with this?

Though I'm not really familiar with Tarkus' Congestion View, I don't think it's involved in your problem.

Currently I do not have a congestion view mod installed unless there is one now included with z. which would result in me using the maxis congestion view and could be distorting my findings. I still am not sure about why my poor sims are driving and my wealthy sims are taking mass transit...

Simulator Z does not include a Traffic Congestion View.  The Maxis Traffic Congestion View works fine, and I recommend its use with Simulator Z.  As for your wealthy Sims, under normal circumstances, 80% of them will prefer to drive, which is the same percentage used in other simulators.  However, if there is severe traffic congestion, as you report, they may move to mass transit.

I think I see what's happening here, based on the simulator you just installed.  All the Alpha releases of Simulator Z (with the exception of the special "MT" version of Alpha 4) have the network capacities that are now used in the Ultra version of Simulator Z.  The High version, which you installed has half these capacities.  So all your network capacities were suddenly cut in half.  Additionally, if your previous version was earlier than Alpha 4, buses didn't count toward congestion; now they do.  Putting these together, it's very understandable that you're seeing what you describe.

The beta version, though (which has actually become the release version), has a better pathfinder and in general is more heavily optimized than the alpha versions.  So for most people, switching from the alpha version to the High version of the current simulator should work.  However, the internal simulator takes a while to adjust things.  How long have you run the new simulator?  It usually takes about five years for the new simulator to completely reorganize traffic patterns into their most optimal form.  You can tell this has happened when the lines in the Traffic Volume Graph stabilize for at least a year.

If you have run the new simulator for at least five years, and the lines in the Traffic Volume Graph have stabilized and you still have problems, this means that your city is built in such a way that it needs the higher capacities it was using before, and you should switch to the Ultra versions of the simulator and Traffic Volume View.  This should definitely fix your problems.  Please try these approaches in the order I have listed them, and let me know how it works out.

[gn_leugim]

Hi there..

I've download the new NAM today, and tried your simulator.. I installed the medium one.. when I started on of my cities it happened something weird.. the city was 25k pop.. and suddenly the population dropped to 10k..  15k people left town as they didn't have jobs.. something that they always had.. the traffic volume graph showed a drop of all types of traffic after 3 months running the game.. I repeated the experience, this time without moving a thing.. just to see what happens.. the same.. about 15k became jobless without reason.. the only thing I've changed from the last time I entered that city was NAM, in particularly the traffic simulator.. Any guess of what happened? 

[z]

When you change traffic simulators, especially to one that is very different from your old one, you will always get the dropoff of traffic you mentioned, although when it comes depends on the particular city.  This is because the new simulator has to recalculate routes for your Sims, and in the mean time, some of them don't have any routes to work.  In most cities, the effect is small enough not to have any effect on the population, but in some cities, such as yours, it may.  Fortunately, this is a temporary phenomenon.  If you keep running the simulator, you will notice that after a number of months your traffic will suddenly rebound to its previous level or close to it, and your Sims will quickly move back in.  Over the next few years, traffic patterns will gradually change to fully accomodate the new simulator.  At the end of this time, your traffic patterns should be much better than before you switched simulators, and your city growth should be quite healthy.  Try running your city a few years (you might want to save a copy first) and let me know what happens.

[gn_leugim]

ok then... I'll try to run the city for some while.. I did it too for other city, and in that one no change was notice 

I'll soon give news 

[b22rian]

ok then... I'll try to run the city for some while.. I did it too for other city, and in that one no change was notice 

I'll soon give news 

Hello Gn leugim.. Please run your cities for at least 6 game years.. before reporting back to us..
                       Even if you feel you have solved the issue..we would like to hear back from you..

Thanks, Brian

[gn_leugim]

well, here is the result.. I run the city for about 6 years..without doing anything.. just let it run.. no big change =1
first, let me show city, Zone map:



and Trafic map:



here we can see the initial step, where most of the people stops commuting..



and here are the results after 6 years.. 









So, what do you think? 

I'll cya tomorrow as I have to go to bed now  I have test tomorrow 

[sumwonyuno]

I've downloaded the new NAM + RHW and reinstalled the CAM, and I've just been overwhelmed and giddy , therefore I haven't done any sort of testing of my current region yet.

gn_leugim this does sound like what I went through.  Your city isn't large, doesn't seem that complex and assuming you have a decent configuration, the simulator should have reached an equilibrium by 6 years.  Is this the only city tile with jobs?  From my experience in using Simulator Z, no-jobs zots and abandonment are caused by 1. the simulator going so fast they indeed go over the 6-month job-hunting limit when commutes are recalculated and 2. there really are a lack of suitable jobs.  I notice in your pictures that the number of R$ sims going down, while R$$ and R$$$ aren't.  I can't tell the exact distribution of the jobs, but I can guess that there might have been too much R$.

Also I've noticed that the no-road-access zot sometimes appears in newly-built homes (groups of ~ 3-6) that do have road access.   In the query it says abandoned due to commute time.  It's probably related to the 6-month limit, but it just happens when the R zones are developed.  Everything else around will act "normal" (find jobs or abandon).

[z]

gn_leugim:  Thanks for posting all those pictures!  They are extremely helpful in seeing what's going on.  And the good news is that I think you're in better shape than it appears at first.

I mentioned before that a traffic drop is normal when switching simulators.  But usually it's no more than about 30%, and there's no effect on the city population.  Your traffic drop is about 60%, way higher than I've seen before, and this is what's causing the population drop.  Since the Sims actually leave town, the traffic doesn't rebound in a few months the way it usually does.

So what's causing this unusually massive traffic drop?  It's not Simulator Z; switching to any very different simulator would have the same effect.  Instead, there are some unique characteristics about your city that are involved here.  It's hard to tell for sure with the current amount of data, but I would guess that it's a combination of your city's small size, which makes it very vulnerable to fluctuations, plus the fact that a large percentage of your jobs are connected to the island where your residences are by a single bridge.  This means that the traffic simulator must route a lot of Sims over that bridge, but the internal Maxis routing code limits the rate at which Sims can be added to a single route.  So when routes are recalculated when the simulators are switched, the bridge acts as a bottleneck to the whole process.  Evidence for this can be found in the sharp drop in commute time, which would be expected if the bridge usage has declined significantly.

This doesn't mean that Simulator Z won't work here; it simply means that since your traffic decline was so deep, it will take longer than usual for things to recover completely.  There are some encouraging signs here.  On your Population and Jobs graph, your middle-income Sims' population has increased significantly since the simulator switch, even though the overall population has declined.  So you're getting a better population mix here; this is important if you want anything other than low-wealth jobs.  Industrial jobs are gradually rising.  But most important is the population on the RCI Totals graph.  It started a little over 25,000 and dropped down to 13,000.  But currently it's at 20,000, which is the highest it's been since the drop and almost 80% of its previous high, and it's headed almost straight up.  It looks to me like things are already improving here.  But due to the fact that the initial traffic drop was so sharp and you lost so many Sims, it's hard to say exactly how long it will take to surpass your old high.  Yet that straight spike up at the end of your population graph is very encouraging; that's the best upward spike you have in your whole graph.

So I would simply recommend running your city longer.  Run it another fifteen years if you have to, though I don't think it will take anywhere near that long to restore your city to full health.  Please let me know what happens.

[sumwonyuno]

First impressions of the new NAM Jan 09:

Wow, z, did you do anything to the simulator before you gave it to be included in the NAM?  I need to thank you again that now commute patterns are the most real-life-like yet.

I reinstalled the CAM, and I am able to manage my abandonment issues in the city tiles I've updated so far.  This has had the effect of adding even more residents and increasing traffic volumes.

First thing I noticed w/ the new NAM was the congestion view was much more checkered.  Due to the intersection effects, tiles around intersections became red.  As I ran the simulator for no less than 10 years in each tile, traffic became even worse.  This is not a bad thing, because the Sims are commuting in much more expected patterns.  The percentages among walking, bus and car are generally about those in real life.  I'm getting to the point of High doesn't seem like it has enough capacity.

In the city tile picture with 26000 connection walkers, before I had installed the NAM today, it was past 50000 on the westbound-lanes' sidewalk, then with about 9000 cars, and a few hundred on buses on the eastbound lanes.  Today with the new NAM, almost 29000 cars are going eastbound, almost 26000 are still walking eastbound on the westbound side, and no buses from the boulevard.  Even on Ultra this would be over-capacity.  At this moment, the commute time graph reports under 3.5 minutes(?) for this city tile.  However, I actually have too much highrises (and therefore commuters) in this city tile.  Once I fix that, I expect the traffic volumes to be lower, congestion to be lower, and get into a situation where there isn't a mass of connection walkers.

In my eastern suburbs, on the east edge of one city tile, the single avenue is carrying over 19000 cars going westbound.  The avenue transitions to a highway which ultimately carries over 25000 westbound at the western edge of the city tile.  Also on the western edge are 3 road connections with about 6000 cars and few hundred buses each.  Commute time graph reports over 140  .  I haven't updated my downtown tiles yet, but I expect that I'll get into situations that will warrant a switch to Ultra.

z, you said an intriguing thing about gn_leugim's situation with the bridge:  Maxis limits the rate trips are added to a single route.  I'm thinking this could also relate to my region where there are such few thoroughfares and options to handle a population with high density.

[z]

The version of Simulator Z in the NAM is the unmodified Beta 1 version.  I simply upgraded it to the release version when nobody could find any bugs in it.  However, Simulator Z does interact strongly with the CAM, so if you manage your CAM better, Simulator Z will automatically work better as well.

From the ReadMe included with the NAM:

Which simulator version is appropriate for a particular city depends primarily on two things: the population of the city, and the amount of rapid transit (rails) available. Less capacity is needed for lower population cities, but less capacity is also required for cities with a lot of rapid transit.

As you have no rapid transit, you will need a higher capacity simulator than the same city with rapid transit.  Also, intercity commuting raises capacity requirements, as you have the same Sims counting toward traffic in multiple cities.  The Ultra version of Simulator Z was originally designed to handle the higher capacity requirements of intercity commuting.  But if you combine extensive intercity commuting with a lack of rails, you're going to get significant congestion even with the Ultra version.  That situation is a lot like Los Angeles, which has a very large number of expressways, but the worst traffic congestion in the country.

Due to a bug in the game, it's impossible to get the Commute Time numbers to be completely accurate.  And the numbers of one city can't be compared to the numbers of another.  Instead, you just want to look for trends in the graph.

z, you said an intriguing thing about gn_leugim's situation with the bridge:  Maxis limits the rate trips are added to a single route.  I'm thinking this could also relate to my region where there are such few thoroughfares and options to handle a population with high density.

This effect is generally not visible during normal play, where traffic patterns change gradually.  Normally, you see it only when switching simulators.  I'm rather sure it's not related to your situation; a simple lack of rapid transit is enough to explain what you're seeing.

[gn_leugim]

So, if I understood, if I run the city a even more time, I'll get the situation normalize?  I'll try to run further then.. I'l give simulator z a last chance  (joking ^^)

i'll report soon..

EDIT:

I found the reason for all this.. is about NAM and not the simulator.. all started when I built a new bridge.. all people became happy with jobs.. but then I notice something weird.. most of the people that crossed the new bridge returned to the island through the old bridge and then stop at his work, on the island.. weird I thought.. then I remember to type: DrawPath on the console.. and I found this:



this roundabout is a major artery.. thought it flows all the traffic that goes from the most of the island to the bridge..
with the transition to NAM the roundabout lost his paths (or something like that) so, I restarted (for the 10th time lol) the city, and the first thing I did was to rebuild that roundabout.. and voila.. it is growing again, all working fine  )

I'll report this to the NAM issues thread.. I think that this could interest them

[z]

With the formal incorporation of Simulator Z into the new NAM, a more complete RTMT patch has been constructed and released.  RTMT users should read this post for details and access to the patch.

[z]

There is now a dedicated support thread for Simulator Z.  If you have questions about Simulator Z, or need help in using it, please post in the NAM Traffic Simulator Z Help thread.  Thanks!

[z]

Although the main work on Traffic Simulator Z is finished, from time to time there will be some development.  As this is the original Simulator Z development thread, it seems to make sense to continue discussions and announcements of such development here.  I have renamed this thread to reflect this focus.  Support issues will continue to be addressed in the NAM Traffic Simulator Z Help thread.

The issue I would like to address right now is street capacities, and especially in the context of SAM streets.  Simulator Z has been out long enough now that many people have experience using it with SAM, and streets in general.  Do the capacities of the various levels of the simulator seem about right for these streets?  Or do people feel they need to be adjusted one way or another?  Any feedback you can furnish will be helpful for the next release of Simulator Z.

[b22rian]

Im still very happy with the current Capacity level for streets..
And I think its right on the money still..,

Thanks, Brian