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-   -   How much a city can grow? (https://skyscraperpage.com/forum/showthread.php?t=240389)

Yuri Sep 21, 2019 11:28 PM

How much a city can grow?
 
I thought of this thread more as a reflection about present urban areas and whether there is a physical limit on how much a (monocentric) city can grow and still working as a same labour market.

World's largest city is Tokyo, a "monocentric" metro area. In the future, it could be surpassed by Jakarta or New Delhi, both with the same characteristic. Emerging Chinese metropolises, on the other hand, would work differently, be it on the Pearl River Delta ou on the metro areas around Shanghai. Both regions work more as a big Rhein-Ruhr area, a collection of metropolises instead of a gargantuan metropolis.

In South America, São Paulo is transitioning from this Tokyo-model into a Pearl River Delta one:

https://upload.wikimedia.org/wikiped...012202_lrg.jpg

The "Macrometropolis" (a term more and more common) has about 33 million people and growing at a 10% decade rate. Even though São Paulo is the star, it's not big enough to turn Campinas metro area (3 million people) into a mere suburb, even though they touch each other by continuous urban development through Jundiaí and its suburbs and working on a complementary way (Campinas-Jundiaí-Sorocaba triangle absorbing São Paulo's manufacturing and logistic flight, stopping them to move to other parts of the country avoiding a Rust Belt phenomenon).

New York and Philadelphia might be a similar case, even though, they are distinct and have their own worlds. At least in São Paulo's case, all the areas are inside the same state and share the same cultural traits.

Anyway, can we have a 50 million, a 60 million "monocentric" urban area or Tokyo's 38-40 million is a physical limit for it? What are your thoughts?

RavioliAficionado Sep 21, 2019 11:34 PM

The monocentric model is just much less efficient. Having both housing and jobs spread out requires lower average commute distances than having all the jobs in one area and all the housing in a ring surrounding it. There's really no good reason for cities to remain the way they are given modern communications technology. De-centralization makes way more sense and is only opposed by the structural inertia of the major cities existing built forms.

Yuri Sep 21, 2019 11:52 PM

It depends. Tokyo, for instance, is not like that. It has a whopping 4,700 km of subway/rail lines carrying 40 million people daily.

A monocentric city is much easier to build a strong label (Paris vs Rhein-Ruhr) and to attract talents from all their hinterland. A polycentric metro area, with separated labour markets, tends to work as a collection of smaller cities, not cohesive enough to work as big metropolis.

llamaorama Sep 22, 2019 2:48 AM

Quote:

Originally Posted by RavioliAficionado (Post 8694550)
The monocentric model is just much less efficient. Having both housing and jobs spread out requires lower average commute distances than having all the jobs in one area and all the housing in a ring surrounding it. There's really no good reason for cities to remain the way they are given modern communications technology. De-centralization makes way more sense and is only opposed by the structural inertia of the major cities existing built forms.

Is this really true, mathematically? The average of a set of points is the centroid. You can use whatever measure of central tendency you wish but its all doing the same thing.

When jobs are located in a suburb on the north side of the region, people on south side have a longer commute. By definition, the average ends up washing out whatever advantage northsiders have because of the southsiders. It would be the same if everyone met in the middle, in the city center.

There is no escaping the reality that as a city gets larger, citizens can only access the whole of its jobs and points of interest if either average commutes grow longer, density increases, or commute speeds somehow increase. Otherwise, as a city gets larger, the actual amount of places citizens can reach in a reasonable time frame(isochrone) stays the same and the expanded metro in reality is a conurbation of many cities.

What seems to happen in urban geography is that as a city gets really big, its core reaches a limit. Then, neighboring centers start to grow due to their proximity(because transportation and economic benefits are bidirectional) and reach their natural limit, and their neighbors grow, and so on and you get this fractal looking thing similar to the way slime molds grow(read about how cities and mold grow the same way, its fascinating). Even though there is a tendency for us to want to classify these places as unified giant megalopolises, realistically very few people are going to commute the entire distance across them on a regular basis. A resident of Campinas or Riverside is not really living their full life in Sao Paulo or LA. If it becomes impossible to objectively separate where one city begins and the other ends, maybe we could look at cities as being an individual experience - the personal local geography and abstract social and economic networks that each of us lives in that overlap and entangle massively with others. At some point us city nerds have to stop being borderline autistic about population stats and labels and boundaries and just realize that in the real world it runs together, its fluid.

Yuri's question is a real one. Our present modes of transportation mean you can only go so far and so fast and as density increases that effects what transportation we can use. Autonomous cars might increase the potential size of a city, so would high speed regional rail. If more people worked in virtual reality rather than in person the attraction to population centers would revolve around access to things which people's travel time tolerances are higher, like cultural and natural amenities, or access that's infrequent like health care services, then there would be less traffic and people would go further so if people still accepted higher densities you could have very big cities.

M II A II R II K Sep 22, 2019 5:17 PM

In the future cities can grow in 3 dimensions with elevated roads and transit as well as buildings and public spaces in the air on stilts like in the Jetsons.

JManc Sep 22, 2019 5:23 PM

Quote:

Originally Posted by yuriandrade (Post 8694547)

New York and Philadelphia might be a similar case, even though, they are distinct and have their own worlds. At least in São Paulo's case, all the areas are inside the same state and share the same cultural traits.

Anyway, can we have a 50 million, a 60 million "monocentric" urban area or Tokyo's 38-40 million is a physical limit for it? What are your thoughts?

They are distinct right now but who knows what could happen in 50-100 years? Both cities are dramatically different than they were 50-100 years ago and American culture in general is gradually homogenizing. I see less of a cultural difference between here in Texas than the northeast than I did as a kid.

ThePhun1 Sep 22, 2019 5:56 PM

New York would have to decline as America's center of the universe for it to merge with another CSA in any logical way. It already has declined in that fashion to some degree but I mean more like an internal Rust Belt-like decline with Philadelphia picking up some of the outspill, especially the media ventures.

RavioliAficionado Sep 22, 2019 6:03 PM

Quote:

Originally Posted by yuriandrade (Post 8694560)
It depends. Tokyo, for instance, is not like that. It has a whopping 4,700 km of subway/rail lines carrying 40 million people daily.

A monocentric city is much easier to build a strong label (Paris vs Rhein-Ruhr) and to attract talents from all their hinterland. A polycentric metro area, with separated labour markets, tends to work as a collection of smaller cities, not cohesive enough to work as big metropolis.

In the US at least the wealthiest region is the San Francisco - San Jose corridor which obviously has two centers (and lots of smaller towns in-between). Jobs in this region are spread out all along the Bay.

Quote:

Originally Posted by llamaorama (Post 8694638)
When jobs are located in a suburb on the north side of the region, people on south side have a longer commute. By definition, the average ends up washing out whatever advantage northsiders have because of the southsiders. It would be the same if everyone met in the middle, in the city center.

Well yeah, if you assume nobody ever moves to be closer to their jobs then maybe. Although I have to admit I am always amazed by just how "sticky" living arrangements are for most people. Every time I've gotten a new job I moved to be closer to it. It confuses me that this isn't the norm.

Obadno Sep 22, 2019 6:48 PM

Quote:

Originally Posted by yuriandrade (Post 8694547)
I thought of this thread more as a reflection about present urban areas and whether there is a physical limit on how much a (monocentric) city can grow and still working as a same labour market.

World's largest city is Tokyo, a "monocentric" metro area. In the future, it could be surpassed by Jakarta or New Delhi, both with the same characteristic. Emerging Chinese metropolises, on the other hand, would work differently, be it on the Pearl River Delta ou on the metro areas around Shanghai. Both regions work more as a big Rhein-Ruhr area, a collection of metropolises instead of a gargantuan metropolis.

In South America, São Paulo is transitioning from this Tokyo-model into a Pearl River Delta one:

https://upload.wikimedia.org/wikiped...012202_lrg.jpg

The "Macrometropolis" (a term more and more common) has about 33 million people and growing at a 10% decade rate. Even though São Paulo is the star, it's not big enough to turn Campinas metro area (3 million people) into a mere suburb, even though they touch each other by continuous urban development through Jundiaí and its suburbs and working on a complementary way (Campinas-Jundiaí-Sorocaba triangle absorbing São Paulo's manufacturing and logistic flight, stopping them to move to other parts of the country avoiding a Rust Belt phenomenon).

New York and Philadelphia might be a similar case, even though, they are distinct and have their own worlds. At least in São Paulo's case, all the areas are inside the same state and share the same cultural traits.

Anyway, can we have a 50 million, a 60 million "monocentric" urban area or Tokyo's 38-40 million is a physical limit for it? What are your thoughts?

Hard to say, an average city today would boggle the minds of most humans who have ever lived.

JManc Sep 22, 2019 7:25 PM

Quote:

Originally Posted by ThePhun1 (Post 8694937)
New York would have to decline as America's center of the universe for it to merge with another CSA in any logical way. It already has declined in that fashion to some degree but I mean more like an internal Rust Belt-like decline with Philadelphia picking up some of the outspill, especially the media ventures.

It already has. New York itself hasn't diminished but other cities have risen up and stolen a lot of influence away from it over the past 40-50 years.

Yuri Sep 22, 2019 8:32 PM

Quote:

Originally Posted by llamaorama (Post 8694638)
Yuri's question is a real one. Our present modes of transportation mean you can only go so far and so fast and as density increases that effects what transportation we can use. Autonomous cars might increase the potential size of a city, so would high speed regional rail. If more people worked in virtual reality rather than in person the attraction to population centers would revolve around access to things which people's travel time tolerances are higher, like cultural and natural amenities, or access that's infrequent like health care services, then there would be less traffic and people would go further so if people still accepted higher densities you could have very big cities.

Another challenge is world's demographic winter. As population grows ever slower, we'll have less candidates for this new 50 million people kind of metropolis. Urban China is already growing considerably slower, so this would leave us with only New Delhi that could potentially replace Tokyo as world's biggest metropolis.

Quote:

Originally Posted by JManc (Post 8694915)
They are distinct right now but who knows what could happen in 50-100 years? Both cities are dramatically different than they were 50-100 years ago and American culture in general is gradually homogenizing. I see less of a cultural difference between here in Texas than the northeast than I did as a kid.

In this case, aside cultural traits and very separated labour markets, I guess the long distance (150 km apart) and the slow growth of New York and Philadelphia MSAs (roughly 3%/decade) are the major obstacles for both merging as one polycentric metro area.

ThePhun1 Sep 23, 2019 3:15 AM

Quote:

Originally Posted by JManc (Post 8694996)
It already has. New York itself hasn't diminished but other cities have risen up and stolen a lot of influence away from it over the past 40-50 years.

But I was more getting at the idea that NYC would decline into another Miami, Houston, Dallas or Atlanta.

For that to happen, others would have to grow exponentially while NYC neutralized or even shrank some. Imagine if half of NYC's population left for, Philly, Trenton, JC, Newark and South Jersey. That's about the only way it could become a true mega-region and combined area.

pj3000 Sep 23, 2019 2:55 PM

Quote:

Originally Posted by ThePhun1 (Post 8694937)
New York would have to decline as America's center of the universe for it to merge with another CSA in any logical way. It already has declined in that fashion to some degree but I mean more like an internal Rust Belt-like decline with Philadelphia picking up some of the outspill, especially the media ventures.

Quote:

Originally Posted by ThePhun1 (Post 8695302)
For that to happen, others would have to grow exponentially while NYC neutralized or even shrank some. Imagine if half of NYC's population left for, Philly, Trenton, JC, Newark and South Jersey. That's about the only way it could become a true mega-region and combined area.

NYC-Philadelphia is already a single CSA in function. No decline, neutralization, or shrinkage of NYC is needed.

Areas that are much closer physically and culturally to Philadelphia and are within the Philly media market are currently included in the New York CSA (Trenton and Allentown/Lehigh Valley). Additionally, daily commuting to NYC/North Jersey for residents of Bucks County, PA (Philly suburbs) via Amtrak, Amtrak/NJ Transit, SEPTA/NJ Transit, NJ Transit (directly from Trenton), or via bus or personal vehicle is very common.

iheartthed Sep 23, 2019 3:15 PM

Quote:

Originally Posted by pj3000 (Post 8695491)
NYC-Philadelphia is already a single CSA in function. No decline, neutralization, or shrinkage of NYC is needed.

Areas that are much closer physically and culturally to Philadelphia and are within the Philly media market are currently included in the New York CSA (Trenton and Allentown/Lehigh Valley). Additionally, daily commuting to NYC/North Jersey for residents of Bucks County, PA (Philly suburbs) via Amtrak, Amtrak/NJ Transit, SEPTA/NJ Transit, NJ Transit (directly from Trenton), or via bus or personal vehicle is very common.

Yeah, there is no break in development between NYC and Philadelphia. You can also commute directly from Manhattan to Philadelphia on local government owned public transit.

There's probably a case to be made that a new category should be created for regions that were built around two major cities that have since fused together. It's sort of Baltimore-Washington like but more extreme.

ThePhun1 Sep 23, 2019 4:50 PM

That's not quite what I meant. I definitely knew there was plenty of cross-commuting for example and even some blur in sports loyalty.

I mean more like New York and Philly having some Dallas/Fort Worth or San Francisco/Oakland relationship. That's not happening any time soon as far as I can tell.

pj3000 Sep 23, 2019 5:22 PM

Quote:

Originally Posted by ThePhun1 (Post 8695624)
That's not quite what I meant. I definitely knew there was plenty of cross-commuting for example and even some blur in sports loyalty.

I mean more like New York and Philly having some Dallas/Fort Worth or San Francisco/Oakland relationship. That's not happening any time soon as far as I can tell.

Yeah, I didn't mean to come across as refuting what you're saying. It is a different situation since NYC and Philly are two of the oldest, largest, most prominent, etc. US cities/regions versus those places you mention, particularly since those examples are closer to each other and Oakland and Ft. Worth being more like "satellite" cities for their big brothers in a way. It would be tough for Philly to become a satellite for NYC, without more significant changes like you mentioned.

jigglysquishy Sep 23, 2019 6:42 PM

City population tends to be capped by infrastructure. New York's metro population has largely stagnated. There has also been a stagnation in infrastructure development.

Tokyo being the largest city in the world is strongly related to having the world's most extensive rail network.

kittyhawk28 Jan 15, 2022 6:27 AM

Quote:

Originally Posted by iheartthed (Post 8695514)
Yeah, there is no break in development between NYC and Philadelphia. You can also commute directly from Manhattan to Philadelphia on local government owned public transit.

There's probably a case to be made that a new category should be created for regions that were built around two major cities that have since fused together. It's sort of Baltimore-Washington like but more extreme.

Even still, you probably should not merge the two cities. It makes no sense, they have separate centers of gravity at the end of the day. An analogous argument would be LA and SD, where you can take a a Metrolink commuter train to Oceanside then transfer onto San Diego's Coaster/Sprinter trains, as well as the two metros having contiguous urbanization along the I-15 corridor. It doesn't change the fact that, at the end of the day, they are two cities with separate and distant centers of gravity, linked only tenuously by some spillovers on the fringes of their metro areas. No sane person would consider them one, even if they share deep economic, cultural, and transport links. Same with NY/Philly, just because they share some spillover, doesn't mean you can call them a single metro. Unless, that is, you are fine with classifying the whole of Japan, UK, and the Blue Banana as a contiguous urbanized metro if applying the same density thresholds used to class NYC and Philly as one. Just because you can, doesn't mean you should.

iheartthed Jan 15, 2022 4:12 PM

Quote:

Originally Posted by kittyhawk28 (Post 9504102)
Even still, you probably should not merge the two cities. It makes no sense, they have separate centers of gravity at the end of the day. An analogous argument would be LA and SD, where you can take a a Metrolink commuter train to Oceanside then transfer onto San Diego's Coaster/Sprinter trains, as well as the two metros having contiguous urbanization along the I-15 corridor. It doesn't change the fact that, at the end of the day, they are two cities with separate and distant centers of gravity, linked only tenuously by some spillovers on the fringes of their metro areas. No sane person would consider them one, even if they share deep economic, cultural, and transport links. Same with NY/Philly, just because they share some spillover, doesn't mean you can call them a single metro. Unless, that is, you are fine with classifying the whole of Japan, UK, and the Blue Banana as a contiguous urbanized metro if applying the same density thresholds used to class NYC and Philly as one. Just because you can, doesn't mean you should.

The line between L.A. and S.D. is pretty clear, while the line between NY and Philadelphia is extremely arbitrary.

kittyhawk28 Jan 15, 2022 7:46 PM

Quote:

Originally Posted by iheartthed (Post 9504233)
The line between L.A. and S.D. is pretty clear, while the line between NY and Philadelphia is extremely arbitrary.

Not really? I mean given you live in NY so I understand if your perception, but if you've only ever driven down I-5 then you would think there's a clear geographic separation between the southern fringe of LA at San Clemente and San Diego's northern fringe at Oceanside. This is due to Camp Pendleton, but Camp Pendleton doesn't extend without end inland. Because along the I-15 there is a contiguous chain of cities of Fallbrook (North San Diego County) and Temecula/Murrieta (Riverside County). In fact, these cities have magnitudes higher population densities then the fringe spillovers of West Windsor or South Brunswick townships; Fallbrook has nearly twice the population density of these Northeast suburbs, while places like Temecula/Murrieta have 3-4 times the population density of these Northeast suburbs between NY and Philly. LA and San Diego commuter sheds also mesh around here; Temecula/Murrieta communities are split about 50/50 between commuting to San Diego county versus commuting north/west into OC, LA, or I.E. Of course, by European standards neither of these places would be considered "urbanized area" by any means (or else a bulk of the continent would be considered a single urban swathe, which is ridiculous), but if your going to apply a certain set of standards for NY/Philly in order to insinuate the two should be classed as a single metro, then the same standards also apply to LA and San Diego. Of course, that was beside my point, which was that since both NY and Philly or LA and San Diego developed separately, their centers of gravity simply are not intertwined in the way dual-core metropolitan areas are, no matter how much you improve transit connections between them. Just because I can hop on a bullet train that comes every 3 minutes into Osaka from Tokyo for a business meeting and be back by dinner, doesn't mean the corridor between Tokyo or Osaka should be considered a single metro.

I find that Northeasterners in particular have this kind of mentality of conflating a megalopolis with a metropolitan area (maybe due to a desire to fulfill a superiority complex?). And that's what the term megalopolis is actually supposed mean re: NY + Philly or LA + SD; that is, deeply linked cities who share relationships far more than a typical intercity relationship, but aren't exactly cohesively linked enough to be considered one.


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