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Commuters vs. Jobs

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#1 DOXXP29


Posted 05 April 2006 - 04:10 PM

This is one I haven't quite figured out. I'll have a building, say commercial, and when I query it, I get something like 1498/1532 for jobs. (Which I'm ASSuming means there are 1532 total jobs available and 1498 are taken.) But, when I use the commute query tool, I'll get a breakdown of something like 265 car, 192 subway and 68 pedestrian, which is much lower than the total people working in the building. The number is much lower on almost all of the queries. Even more confusing is when the commute query says "workers: none" (which occurs quite frequently),but the building is not abandoned and in fact has close to full capacity for jobs on the regular query tool. This phenomenon is similar whether it's res, ind or comm. Seems like they're using two completely different sets of numbers, but if most of the jobs are taken and the workers obviously don't live there, it would seem they have to commute. I just don't understand the discrepancy between the two queries.

#2 winonanick


Posted 05 April 2006 - 04:26 PM

I have noticed this as well, particularly in my industrial cities. I assume the are two different groups working here.

#3 Peorth


Posted 05 April 2006 - 06:22 PM

Regarding the discrepancy, I've noticed that too. I have no idea why it is so, but since it doesn't really affect the gameplay I just ignore it.

Abourt the "workers: none" query, I believe this happens when new employment (C/I) buildings are built and the pathfinding engine is still figuring out the work route for sims. If you give it enough time, the pathfinding engine should do its work and the building will have an occupancy figure.

#4 BlackJackal


Posted 05 April 2006 - 07:39 PM

I'm sure some of the difference could be accountd for by carpooling. The commuters information may just be the number of cars parking at the building, and not the total number of people commuting by car? I'm not sure.

#5 mayormot


Posted 06 April 2006 - 04:02 PM

The number of jobs reported by the building query is *not* how many Sims work there!

It's (Number of jobs currently offered in building / Max number of jobs that would be available if conditions were perfect). Your tax revenue and residential demand are calculated based on these numbers, but nothing else is!

So 1468/1592 means the building could offer 1592 jobs, but is currently offering only 1468 because of undesirable conditions: crime, pollution, inadequate fire protection, low traffic (aka "customers"), not enough parks/plazas, etc. What needs to be done to increase the jobs is up to you to figure out using the graphs and views available to you - the game won't directly say. As your city grows and adds services and anemities this tends to sort itself out over time anyway. How many people are actually working there right now? Only the Route Query will tell you that.

Note that farm queries reflect only the number of jobs offered in the farm building - there will be additional field workers not reflected in the building query. Again, the Route Query tool will show you how many people are really working at the farm. A watered farm with perfect conditions can employ a lot of Sims for its fields!

Finally, BlackJackal mentioned the Carpool Ordinance - that makes each car represent 1.2 Sims instead of just one. So if you're using that ordinance, multiply the number of cars by 1.2 (or 6/5, if you prefer fractions), then add the peds to get the true number of Sims working at a building. Gee, make it easy why don't they?

Hope this helps.

#6 DOXXP29


Posted 07 April 2006 - 12:16 AM

Thank You! I appreciate the detailed answer, Mayormot!That never would have crossed my mind. From the way they break that down with conditions,etc, it almost seems like they have some kind of actuarial crew at Maxis to come up with those kinds of statistics. Yes, I do use the carpool ordinance on every city. On some of the ordinances, I can sometimes see a difference in the trends, but I never knew exactly how they affected the statistics. What does still confuse me, though, is the "workers: none" in the route query. The pathfinding engine does update this sometimes, but in other cases, it remains the same even after many years. Maybe there actually ARE no people working there, but I would think that after 50 or so years, the building would show some kind of decrease in wealth or abandonment. Hey, I guess if it was easy, it would be boring. : )

#7 Keiran Halcyon

Keiran Halcyon

Posted 07 April 2006 - 05:02 AM

I have noticed the "Workers: None" message in industrial zones when I have bulldozed the "root" building, but the others still have road access. The others did not abandon due to lack of access, but neither did they reestablish a commute path, either for workers or freight (which, IIRC, caused them to report "Freight Trips: Long").

#8 dpk

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Posted 08 April 2006 - 06:22 AM

Originally posted by: mayormot The number of jobs reported by the building query is *not* how many Sims work there!

It's (Number of jobs currently offered in building / Max number of jobs that would be available if conditions were perfect). Your tax revenue and residential demand are calculated based on these numbers, but nothing else is!

This may explain why I've had constant, impossible to solve commute time issues. Most of my industry apparently have no workers. They send out freight, but have no cars or pedestrians, or anyone.

This is in a city of 700,000 and a region of 1.2M, so there is a lot of inter-city commuting going on. Maybe my main city's workers are heading elsewhere, leaving industry here completely dead?

#9 mayormot


Posted 08 April 2006 - 03:20 PM

DPK: It's very possible that your Sims are commuting off-map instead of working at the local industry. It's more likely than them staying in town, in fact.

There's the way the game intuitively should work, there's the way the manuals say it should work, then there's what really happens. True regional commute path computations and logical pathfinding algorithms bogged down the CPU too much and made the game lag, so Maxis/EA dumbed-down the algorithms before SC4 Vanilla was released. They had to for SC4 to run on even the best 2003-vintage computer (and it was still too much - the first official patch dumbed them down further). Even now, computers aren't even close to fast enough to do what this game really needs to do. So they faked it. The NAM managed to fix the pathfinding within a city to something reasonable (at the cost of major CPU time), but the regional stuff is hard-coded in the EXE. And wow, is it hackish.

The game tries to assign a Sim the nearest available (education/wealth-appropriate) job. The definition of "nearest" is the issue: If there's a job available in a neighbor city, then the distance to that job is considered to be the distance from the Sim's home to the map edge (where the neighbor connection is) - it doesn't consider the additional distance in the next city. This is why neighbor connections tend to "suck" traffic out of your city so strongly, and why it's easier to find Sims jobs in the next town over than it is to get them to work where they live; about 75% of the land in any city is closer to the map edge than it is to the city center. On a small map it's hard to get residents to stay in town at all.

Then there are "commute circles." The game won't let a Sim double-back and re-enter a city that he just came from, but it has no way of knowing that he's doubled back via a third city. Maybe you've heard of the "garbage circle" cheat - A exports to B, exports to C, exports back to A, and the garbage goes around in a circle forever without landing anywhere. This can happen to Sims, too. Sims will commute off-map if the neighbor connection is "closer" than the jobs in-town (and a majority of the time it will be). So, suppose your Sims commute from A to B. When you open city B, if there's a neighbor connection to city C that is closer to where these Sims enter than the jobs are, the Sims will continue on to city C. If C connects back to A, and that connection is closer than the jobs (if any) in C, the Sims will commute right back to A where they started. And then they commute back to B, and the cycle repeats. These Sims never find jobs, your commute time grows to silly levels, and you start getting no-job zots and abandonment (even no-car zots if it gets so bogged down tracing these circles that it doesn't have time to keep its zone and network maps in sync internally). This happens even though you have way more jobs than people. The neighbor connections keep sucking Sims away from the jobs. It's kinda like the Sims are in a kind of orbit.

Meanwhile, the Sims in question have already been assigned a job, but they can't seem to ever reach it because the path algorithms keep pulling them into neighbor connections instead. Eventually they usually give up and abandon due to "commute time" - you might get the "Bermuda Triangle" message from a MySim if this is happening. [MySims are handy that way, they'll at least tell you what job they were assigned, and whether they can get to it. Not good for much else though, except clogging up your news ticker. Unless "hmm" and a picture of a pencil means something to you?] If new residents move in, they're likely to get caught in the same trap. This is yet another way to encounter a false-commute-time issue. It also means that you could end up with thousands of empty industrial jobs and no residential demand, since the game thinks that the jobs are filled. So then you have to de-zone all that housing and rebuild it somewhere else, where the game can find a route. Annoy, annoy...

Then there are what I call "Twilight Zone" Sims - these are the ones whose commute paths took them into a dead-end in an edge city that doesn't have jobs for them. They can't turn around, and they can't keep going. You see them go into the edge city, but when you open the edge city, you don't see them coming in. They just disappear. Build the jobs they want, and then you'll see them commute in. If you don't, I have no idea how long it takes the game to figure out that they shouldn't be going there. I don't think it ever does - never seen it happen. I had a region with 5,000 Sims commuting into a city that contained NOTHING. Not even a windmill. After 50 game-years, they were still going there.

The best (and only) way to avoid all this that I've found, is to be very careful about the region layout and city connections, so that circles are impossible. For any two cities, there is one (and only one) route between them. I build industry at the outer edges of the region, to serve as a "sink" for all those wayward Sims who get pushed out there. Otherwise, I'll get into commute trouble eventually. Grid-cities that connect their grids across city boundaries are an open invitation to commute circles, as are pairs of neighbor connections near a city's outer corners.

OK, I lied- there IS another way, but it's ridiculous: Make it so all your city's neighbor connections meet in the precise center of town (+/- a few tiles but keep it reasonably close). Do not let any roads or zones connect with these routes out of town except at the city center. This forces the Sims to travel to the middle of town in order to get out to the edge - and Sims commuting inbound must travel to the city center before they can go anywhere else. Either way, from the city center, any job in town is closer than the map edge. [Ha!] I've tried this approach, and it makes for some spectacularly goofy-looking towns. But it does, mostly, work. And all that traffic converging makes for a nice commercial area too, at the cost of some congestion.

I've also noticed that the game isn't very good at keeping track of which neighbor city has which things available. I've built an Industrial neighbor city, then seen Sims start mass-commuting into some other city where the jobs aren't, because its connection was closer. Really, you have to look at where the Sims are naturally going to go anyway, then put the jobs wherever that turns out to be. Top-down planning doesn't work out so well unless you're really clear on the dynamics, and even then it's a crap-shoot sometimes.

#10 dpk

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Posted 08 April 2006 - 04:11 PM

Thank you for the very detailed response Mayormot. I didn't realize the job-finding algorithm had so much to do with proximity to the edge. These cities are laid out in grids, it very well could be causing loops. I think in my case it'd actually be easier to restrict the connections to the center of the city boundaries as suggested -- or, at least, set them up near the water where they'd have to travel a long way through that city to come ack. I'm also going to reduce the number of high density residential zones, to try to reduce commute time further.

I may try to move some of the zones from the edges, too.

If I continue to have problems I'll create another thread. Apologies to DOXXP29 for the hijacking.

#11 DOXXP29


Posted 08 April 2006 - 06:11 PM

No apology necessary dpk. You helpfully expanded on issues that I was having and Mayormot gave an awesome explaination. It makes sense now. I was looking for a "sensible" way for it to work, and Mayormot made clear what should have been obvious after playing this for so long...rational logic cannot be used when one is dealing with an irrationally altered algorithm. (Not a slam on Maxis. They did what they had to to make it work and this was probably an appropriate corner to cut. No pun intended.) I'm gonna try the goofy center city approach and see what happens. Thanx!

#12 Peorth


Posted 08 April 2006 - 07:11 PM

Thanks mayormot for the extensive explanation!

Hopefully the pathfinding engine in Simcity 5 will be better. After all, the Maxis people can assume that people have more powerful CPUs this time around.

#13 Keiran Halcyon

Keiran Halcyon

Posted 08 April 2006 - 08:58 PM

We can hope.

Hmm... that city center idea might look a bit less rediculous if tunnels are used. At least, you won't have quite so much wasted surface space.

#14 DOXXP29


Posted 08 April 2006 - 11:44 PM

Just when the numbers theory starts to make sense I get a real commercial curve ball. I have three Brinks Real Estates in a city in a row. (2 are next door, the other 2 tiles away). The query and route query show the following. Brinks #1: 107/212 jobs, 69 ped, 11 car. #2: 143/212 jobs, 16 ped, 104 car. #3: 143/212 jobs, 9 ped, 572 car!!! This gives #1 80 commuters, #2 120 commuters and #3 581 commuters. (No depreciation or any influencing factors. Desirability, wealth, etc are eaual for all three.) Go figure... Maybe this is what I get for trying to improve the city by using numbers and statistics instead of just doing what instinctively feels right.

#15 mayormot


Posted 09 April 2006 - 04:25 AM

Originally posted by: DOXXP29 #3: 143/212 jobs, 9 ped, 572 car!!!

That's just a little game lag. When you see more commuters than than jobs like that, it means that the query tool is updating its internal data. Check back in a few minutes and it should clear itself up.

As near as I can tell, this is a quirk with the query tool and isn't reflected in the other simulators - which makes sense, because the traffic query was not present in the original game, but added with Rush Hour.

Hope this helps. Sounds like your city is fine.

EDIT: Oooh, that tunnel idea is juicy! I must try it!

#16 Keiran Halcyon

Keiran Halcyon

Posted 09 April 2006 - 03:08 PM

You could even extend the tunnel all the way to the other side of the map, so that in order to use a neighbor connection, sims would have to travel all the way across. Of course, I wouldn't recommend this if you actually want your sims to try to commute off-map, but it doesn't seem like you (mayormot) do.

Tell me, is this a problem with island chains connected by ferries? I've always wanted to try such a map, but from what you say, it might be inpossible to get working properly.

#17 mayormot


Posted 09 April 2006 - 04:26 PM

I don't play with ferries much, but IIRC, ferries have a significant entry time cost (more than toll booths), which is why the Sims will go pretty far out of their way to use a bridge instead if they can. I don't know exactly what that time cost is, since the ferry settings are hard-coded in the EXE like the seaports are.

There was an experiment done here on ST a couple of years ago about the chain-of-islands situation. IIRC, it found that Sims can only ride the ferry to an immediate neighbor - to continue to the next city on, they have to exit the ferry, make a U-turn, and get back on the ferry again. That makes them pay the time cost again, so I'd expect Sims to go pretty far inland to find jobs before they get back on that slow boat. Also, the time cost is big enough that commute circles shouldn't happen with ferries.

With ferries, the Sims pay the time cost when they get on the boat, then the trip is free regardless of distance (just like freight going out through seaports). So if a seaport functions as a map edge, a ferry is like 64 tiles of road (rough guesstimate) leading to *all* the map edges.

BTW, I don't mind Sims commuting off-map, it's just that I want them to go somewhere logical. The "tunnel to center" model would be the extreme case that forces Sims to take all the jobs in a city before commuting off-map. One could do the tunnel thing on some edges and not others, to decide which Sims commute off-map in which direction, and which other Sims stay in town. Moving the "center" a little toward one edge or the other will have an effect on which way Sims go too.

Either way, If I zone a bunch of industrial and provide 10,000 jobs on the south side of a city, then zone residential to the north, I probably want the Sims on the north side to work at those industries, not start pouring out a neighbor connection because it sees the jobs at the train station on the far side of the next town as being "closer."

#18 Neddiggis


Posted 09 April 2006 - 05:26 PM

the time cost at each station for the ferries isn't actually that unrealistic as if you were riding one you would have to wait at each port is stopped at between your embarking and disembarking.  Making them get off then on again is just a way of applying it I guess.  Not sure of how high the cost is though, that may be high.

#19 Keiran Halcyon

Keiran Halcyon

Posted 09 April 2006 - 06:19 PM

Hmm, that makes sense. For example, restricting access to connections north and south while leaving east and west unimpeded, region-wide, will effectivelly kill the possibility of loops.

#20 Brasdf


Posted 09 April 2006 - 06:47 PM

Wow, awesome detail mayormot!  So if I wanted a region with big grid cities with lots of neighbor connections but no loops, I could do something like this right?

#21 mayormot


Posted 09 April 2006 - 09:24 PM

Brasdf: That is exactly how I lay my transportation systems out! My regions are smaller, but that's the concept I use.

Neddiggis: I agree, the ferry system is realistic enough... as much as it can be without truly calculating the time the ferries take on the water. Since it doesn't do that, the game has to force Sims off the ferry in the next city. Otherwise, it would take zero time for the Sims to continue to the next city, and the next, and the next - they'd either get stuck in a commute circle and never get off the boat, or else end up getting carried to the edge of the region. And the entry time of a ferry has to be high to keep Sims from turning around and riding again unless they have to.

Keiran Halcyon is way ahead of me with great ideas for making it all look good.

#22 Keiran Halcyon

Keiran Halcyon

Posted 10 April 2006 - 04:43 AM

Then I've got one more for you. In the previous example I gave, you could add easy N/S connections via mass-transit networks (excluding buses), keeping mass transit restricted in the E/W direction. Since sims cannot change from mass transit to car, and in most cases, cannot change from car to mass transit, this should not result in loops either.

I also wonder if the judicious use of toll booths could help out....

#23 Brasdf


Posted 10 April 2006 - 09:39 AM

Keiran: Great idea about using non-bus MT separately from roads and still not introducing loops! I wouldn't have thought of that.

Also, it seems like connecting cities only in the E/W direction would work only if all cities in the region are the same size. For example, here are two big cities and two small cities that form a loop even though the only inter-city connections run E/W:

#24 BBGun06


Posted 10 April 2006 - 09:57 AM

    I frequently use toll booths on highways out of my cities.  It does help some, from what I can tell.
    I had a set of ferry terminals on both sides of a river.  people used them so much that the avenues outside were in the red.  I built a bridge about ten tiles away, and they still used the ferry! This was probably a fluke, when I installed the better pathfinding with the NAM the traffic evened out some

#25 BlackJackal


Posted 10 April 2006 - 10:26 AM

All road links between my cities are accomplished with highways and I always place a toll booth near the connection. I think it helps as I've never experienced this problem before.

#26 Imcafin


Posted 10 April 2006 - 02:02 PM

I went and applied some of the things discussed in this thread to an old city of mine (150k inhabitants). Severing excess connections cut the commute time from 70+ to 40 (NAM 10x speed 10x commute). In my case the worst offender was the underground not roads.

While severing connections in an area that is supposed to be a part of a dense urban area is not realistic, I'll take the more spread out traffic any time. Now people actually go to work in the middle of the map.

Nice analysis mayormot (and the rest).

#27 Keiran Halcyon

Keiran Halcyon

Posted 10 April 2006 - 02:32 PM

Brasdf, yes, that forms a loop, but a sim would have to traverse the entire width of the medium cities, at the least, to drive it. The hope is that upon entering the medium city, the sim finds a job there that's closer than the opposite map edge.

#28 jackel.22


Posted 11 April 2006 - 12:01 AM

wow mayormot thanks for the in depth explanation, thankfully ive never really got to the stage of circles because im a toll booth tyrant, i often have up to 10 in a row on all roads leading out of each city. i also tend to use the n,s,e,w connections as well - sothat sims have to travel to the center then out. Keiran Halcyon im going to try the tunnel idea out thanks for the idea.

#29 DOXXP29


Posted 11 April 2006 - 01:36 AM

You have the right idea with the toll booths, Jackel.22, cuz they can be your best friend sometimes. I've used the same strategy on all raods leading into the downtown area and even in the MIDDLE of downtown to force them to use mass transit. I came upon this when I switched the NAM to "better pathfinding" and found they all abandoned mass transit for the improved road capacity. The toll booths can counter this in areas where you don't want them to go back to the roads, and if you use the "toll booth boost" mod, you can get yourself some nice change to support the mass transit from the rich folk who still insist on driving. Just be careful if you place them in res areas, cuz you'll get no car zots if they're blocking a lot.

#30 sebes


Posted 11 April 2006 - 01:59 AM

This is a great discussion and most valuable information. I have a 8.000.000 region with many empty C/I zones in all cities and ridiculous commute times... It must be the 'Sims in orbit' phenomenon. Thank you Mayormot for your explanations.