Station Pathfinding Fix

[BlakeMW 84]

This is related to my topic in the Game Experiments forum on

Station Congestion and Pathfinding

Originally the topic was working around the flaws, since it's moved to a modding solution I've created this topic.

To summarize the problem: With default settings Stations have zero move cost and instantaneously teleport the Sims to the far side - the pathfinder thus considers them a shorter path than the road/track. This causes problems since the passer-through traffic also count towards station usage - which can max out station capacity and thus jam up networks that would otherwise be efficient.

Although a contrived example, this screenshot succinctly illustrates the problem; Bus stations are used for short-cuts around corners and on diagonal roads. Monorail stations on a parallel track are considered a shorter path than the straight through track; rail stations are used as teleporters at corners and on diagonal track.

Modifying the Transit Switch Entry Cost in the station examplar greatly improves this:

The bus traffic now correctly goes straight through, bypassing the useless stations. The Monorail traffic also bypasses the unused station. The paths look much better in this example, and in real cities the displayed station usage will be dramatically reduced - in fact reduced to actual usage (Sims actually boarding or disembarking at the station). The railway stubbornly defies me.

The Transit Switch Entry Cost gives a fixed commute time cost for traversing through a station (this time cost is unaffected by station congestion), road/track however has a variable commute time cost, dependent on base road speed and congestion. Therefore in order for bus stops to never be a valid short cut, they must cost more to use than the slowest transit tile - this is the fully congested street intersection.

A bus stop time cost of 0.2 appears to be sufficient to entirely eliminate taking short cuts through stops at corners/intersections.

For the monorail example, a much smaller value works, as small as 0.01, and 0.05 should work for fully congested networks.

Altough my knowledge of Gameplay mechanics is considerable I know next to nothing about modding, altough I've obviously figured out enough to hack together fixes for my personal use.

Reasons to impliment this fix:

1) Realism. Stations shouldn't be free to move through.

2) Realism. Sims should not hop off the bus at random stops, then back on as it rounds the corner. Unused stations should be bypassed.

3) City Effeciency: Stations are used purely for embarking and disembarking, rather than as thoroughfares. Works more intuitively and consistintly (no differnece between stops on corners and those on straights), providing accurate usage statistics.

4) Balance change? Since Transit Switch Entry Cost works, it could be used to create different tradeoffs between road and track MT. Like stations have a high switch cost, but the tracks much higher capacity so don't get congested.

[TinySim 4]

Will a fix for these shortcutting sims be released?
That would be good, and if possible, it should be made so that downloadable stations get the same value.

[T Wrecks 10,209]

@ TinySim: Read what he wrote; the answer is there. He would like to release such a mod, but since it's beyond his modding skills, he's looking for a good modder to help.

As for downloaded stations, this will be impossible or at least very hard work. You'd have to include stats for every single station, and that's not likely to happen. Look at mods like the industrial jobs quadrupler: It works for all in-game buildings, but if you want to change the job numbers of downloaded industrial BATs, you must mod every BAT yourself.

@ Grater: I have already read your other thread with great interest, and now this one... I don't know how to thank you for these revealing insights into the game's mechanisms. I will take what I learnt here into account the next time I build a city, although the only real workaround will be a mod like you suggest. Sadly, my modding skills are very humble and limited to non-transit system stuff. But I do hope you find someone, because this MOD is much needed now I see how buggy and unrealistic SC4 is in this respect.

[Colijn 0]

Thanks Grater! This is exactly what I wanted to know. I tried only much higher settings for the Transit Switch Entry Cost (as there is no explanation what the value of it means) like 2 and 10, but in those cases the network is much less used.

So the right value for Bus stops is 0.2 and for monorail 0.05; do you know the right values for the other networks (train, elevated rail) as well? Is it somewhere inbetween?

[Andreas Roth 607]

These are some interesting experiments! Did you test your modified stations in a real city as well? How are the commute times affected? Are the stations used as good as normal, or notable lower? Do you get those bus-ped-bus-ped-bus jumps also in a normal city, where jobs are provided at the destination of the commuting sims? I'm asking because every station provides a (small) number of jobs, and in your second pic it seems - although the paths look much better - that more residents from the houses in the lower right corner seem to have lost their jobs and moved out. What happened to the monorail station in particular? Is it still used?

[BlakeMW 84]

0.1 SHOULD work well for el rail, subway works okay by default for some reason.

To anwser the above question, in the screenshots there are 3 seperate residential blocks, one taking bus, another rail, another monorail, all those converge onto one railway track that then exits the map - it was that railway I clicked on to only show the straight through traffic on all 3 network types.

I've tested it in real cities. A value of 0.2 adds a small amount to bus commute times - maybe 5% - not a large amount. For a long time I've designed my cities to not have bus stops on corners, I expect that a city designed by a normal player would enjoy improved commute times, especially if there are fully congested bus stops on corners - as freeing up the congested bus stops means more sims take the bus instead of car, less cars on the roads means less congestion and higher bus speeds.

Getting back to the real city tests, I was still enjoying 70-80% bus usage, much the same as I usually get with standard NAM better pathfinding settings, altough Sims might be slightly more inclined to walk or take the car over shorter distances. In short adding a small entry cost to bus stops appears to be all positive.
The entry cost on the monorail station is so low that I can't imagine it possibly has an impact - in effect it makes the station to station distance 2 tiles longer, which is nothing with the speed of monorail.

The problem with the passenger rail stations eludes me, making a REALLY high entry cost, like 1.0, will stop sims using it as a shortcut, but it also has a large impact on commute times. Then again realistically Rail stations should only be placed on straights, where they also don't get used as shortcuts.

[Andreas Roth 607]

I remember a discussion we had in the German SimForum some time ago, where someone complained about heavily overused rail stations next to the city borders - I suggested bypasses similar to the monorail station in your pic, but as far as I remember, it did't work too well. With adding a very small transit switch entry cost, the problem could be resolved. The only drawback I could imagine is a severe drop in your monthly income, since many large cities make their plus almost completely from transit fares of their overused stations.

[BlakeMW 84]

As far as I can tell the income from fares is based entirely on distance, altough I guess I could test this. For sure I make a heck of a lot of fares income in my cities where I carefully avoid placing stations where they can be used as thoroughfares.

[BlakeMW 84]

I've tested it quite conclusively. Sims using stations as thoroughfares reduces fares income. How so? It's because they walk over one or more tiles rather than riding the MT along the road/track - they don't pay fares when they are walking.

[BlakeMW 84]

I'm trying a VERY interesting experiment at totally changing the balance between bus/car etc. Here is the basics:

Road based Transit:
1) Raise car speed and lower bus speed, so that busses are slower than cars. (Possibly with an exception for highways)
2) Make busses immune to congestion with a low transit switching cost.
Combined this means that sims will tend to drive, until congestion becomes bad enough that they are forced onto busses [if they are available].
Track based Transit:
3) Subway and Elrail should have increased track capacities, but still suffer from congestion. Low switching cost (possibly ElRail could be immune to congestion - due to lower density of stops).
4) Rail and Monorail should be unlimited capacity with a relatively high switching cost. Rail speed should be lowered somewhat.
Income:
5) Bus fares should be halved, other fares increased by 50%, monorail increased by 100%. Currentely all forms of transit give exactly the same fares income.


The new design for cities:
Cars should be the preferred way to get around if it's convienent, however once roads get congested Sims should start looking at other MT options.
Busses are slow but reliable (think bus lanes and right of way), Sims should use them for short distance travel mostly, for short commutes, or to/from MT hubs.
Subway should provide an alternative to busses, with higher speed and underground construction, however trying to use it for long-distance commutes should result in congestion problems.
Rail and Monorail should be the ultra high capacity, long distance transit trunklikes. Much faster than busses.

As a comparison, here is how smoothly running cities currentely work:
Cars are what certain stubborn sims use, despite busses being faster.
Fixed track transist gets congested to the point that it's slow as bus travel, this makes it unattractive for long distance travel. Or Sims just take the bus directely to where they want to go.
Most Sims move around by bus, since busses are immune to congestion giving roads effectively much higher capacity than track. (for example a road is green with 800 cars and 5000 busses, while a rail would be red with 5800 Sims using it, red rail is slower than green road).
In short, all mass transit other than bus is basically cosmetic, since busses work better.

I've also attached the fixes for Bus, Monorail and ElRail. Note you'd need to rebuild existing stations for them to take effect. Only congested stops on corners/intersections would benefit from being replaced.

[Superchan 23]

looks like a good mod.

[J_McSim 0]

A very interesting topic, transit switching in this game, I'm beginning to beleive, is a most curious creature.  The entry cost idea is a good one and works well, ofcourse for custom stations . . .

 

I noticed these rather interesting 'actual usage' numbers a while back, never got around to looking into it though . . .

https://www.simtropolis.com/idealbb/files//ss-jpm-01.jpg align=baseline>

the GLR and El. Rail stations perform as you'd probably expect, the stations out in the open draw no new passengers, but show an 'actual usage' equal to the number of passengers passing though... ie

they 'switch' in the station and count towards usage.

 

The subway station in the open however has a usage of 0.  96 sims are passing through there, but none of them are counted on the stations usage, so subways are much more efficient than may have been assumed. . . as I said, never got around to looking into it, maybe there's something 'wrong' with the default subway or el rail station, probably worth investigating anyway, I haven't the time, but if anyone has the time and knowhow, this would be worth looking into.

https://www.simtropolis.com/idealbb/files//ss-jpm-02.jpg align=baseline>

 

https://www.simtropolis.com/idealbb/files//ss-jpm-03.jpg align=baseline>

[BlakeMW 84]

Yup. Subways are, for whatever reason, uneffected. Maybe because the tracks are built on a different layer, or maybe there is some kind of added switching cost.

Elrail works exactly the same as monorail.

[yiplong 1]

Yeah, this is a huge problem. I built some train station, and always wonder why does a station in the middle of nowhere has high usage. Appearantly, people get off the train, and reboarded.

[SamFlash 0]

Date: 9/20/2005 9:53:07 PM Author: yiplong Yeah, this is a huge problem.  I built some train station, and always wonder why does a station in the middle of nowhere has high usage.  Appearantly, people get off the train, and reboarded. 

quote>

I've wondered the same thing.  This is a fascinating discussion about issues that may never be solved to everyone's complete satisfaction.  I'll be very interested in any mod that arises out of all this.

[TheCrybKeeper 287]

Grator: I like the plug-ins and the STEX as much as the next Sitizen, but what if I am correct in my exp CJ: Grid Secrets? Then those stations should behave a certain way for a certain reason.

 

Sitizens

 

If I am correct then;

 this is not a flaw, but actually quite purposefully done. All you must do, is figure out the numbers and the pattern for laying track. Not according to real world use. I know, Terrible thought, isn't it?

 Buses/Subways/ELs, they all follow a very different path for a reason. The stations must be placed a certain way, to be most efficient and must be allowed to, calculate use in the manner already specified, by the game developers.

 

Not only that; each transportation venue has their specific commuters: buses take industry, Subways take commercial, highways connect neighbors, etc.

 

Just my theory, so please, no one get angry just yet. Instead read my Experiment and yell at me there. I actually believe I could be wrong, so please help me out by giving some feedback?

[BlakeMW 84]

I'll post an experimental city journel demonstrating a city with excellent bus usage, over 80%.

Interestingly all a modding solution for the bus stop does is allow bus stops to be placed on corners, but placing bus stops on corners is not actually more effective (in terms of # of buildings serviced), nor is it realistic, in real life intersections are too busy for a bus stop and all bus stops are on straights.

[TheCrybKeeper 287]

If you post that CJ, I will follow it, Grater. I am not trying to kill your thread, honest. I too am just looking for the answers to transit and commute times.

All the bus stops in urban U.S. cities, are mainly at the corners/intersections. From what country do you hail, Grater? Your profile is empty.....

[tungston 19]

Date: 9/22/2005 4:34:20 PM Author: Grater I'll post an experimental city journel demonstrating a city with excellent bus usage, over 80%. Interestingly all a modding solution for the bus stop does is allow bus stops to be placed on corners, but placing bus stops on corners is not actually more effective (in terms of # of buildings serviced), nor is it realistic, in real life intersections are too busy for a bus stop and all bus stops are on straights.

@Grater:  I have followed you experiments with great interest, and I find them fasinating.  Although, I wouldn't place my stations as you have for your experiments.  I try to place my transit stations in a grid patern appox every 8 or 10 tiles.

 

Andreas Roth makes very valid point, a major source of income for my cities comes from fares.

 

I must take issue with frndofyaweh, transit stations are not at all specific to any aspect of the game.  I use all transits (roads, grd rail, bus, subway, monorail) for all ocasions,  all RCI's, and neighborhood connections, and all get used in each instance.

 

I am looking forward to your CJ, Grater, I am always on the lookout for ways to improve my game.

[TheCrybKeeper 287]

Tungston: Hello again fellow sitizen. It's alright that you take issue with me. I try and remain unbiased....Try anyways. lol.  But,  at the very least, check My exp CJ to see if I may be correct. if you do not wish to comment there, that is okay.

I think there may be some validity to my theory: It is working so far to 371,000 sims and I have a surprising update coming, that will show even more revealing MT.

 

[Bones1 96]

I agree with tungsten. All mass transit types function the same: it carries people to work, whether that be industry or commerce. It doesn't matter if it's bus, subway, or rail; they all are used for the same purpose. (Except rail which can also carry freight.)

Cars, however, do have a preference according to the wealth of the sims. R$$$ prefers to drive rather than take MT. I believe R$$$ will take MT if it has to, but there's a commute penalty applied so they won't go as far on MT as lower wealth sims.

[kassarc16 4]

Thanks for the fix, the bus stops always annoyed me. By the way, does this modify the RoadTop MT too, or just base game stops?