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Transport - general

Mar 22, 2016

Will Sydney and Melbourne implode as they get bigger and bigger?

The idea of Sydney and Melbourne doubling in population to eight million by the 2050s conjures images of total traffic gridlock and super long commutes. Fortunately, it's not likely


The actual numbers of jobs reached in less that 30, 45 and 60 minutes as functions of the total numbers of obs in 40 US cities in 2000 (source: Angel and Blei)
Commute time don’t explode as cities get bigger. The actual numbers of jobs reached in less that 30, 45 and 60 minutes as functions of the total numbers of jobs in 40 US cities in 2000 (source: Angel and Blei)

There’s a popular doomsday scenario where Sydney and Melbourne collapse from the intolerable burden of their populations doubling to 8 million by circa 2050. Traffic grinds to a halt and commuters take forever to get to work according to this dismal prognosis, resulting in an epidemic of social problems like increasing rates of mental illness, family breakdown, obesity and disabetes (e.g. see here, here and here).

The fear of size has lead various commentators to argue strongly for growth to be redirected to regional centres. Indeed, in the absence of a convincing environmental or equity rationale, it’s one of the fallback arguments trotted out in support of huge public subsidies for High Speed Rail.

Yet some of the world’s most productive metropolitan areas are already much bigger. London’s population is 14 million, Paris is 12 million, New York is 20 million, Chicago is 10 million, Dusseldorf is 11 million. These are also some of the most desirable places in the world to live so it’s possible their size might actually be an advantage.

It’s not a mystery; a new study confirms what’s been known for donkey’s ages – larger cities are more productive. Commuting and the productivity of American cities, by Shlomo Angel and Alejandro Blei from NYU’s Stern Urbanisation Project, examined 347 metropolitan areas in the US and found that when the population of a city doubles, its GDP increases by more – on average by 120%.

Incomes aren’t the only positive thing that increases with city size. So do myriad social opportunities like the chance to meet other people with similar interests and the availability of a larger number of prospective friends (see Are bigger cities less diverse? and Diversity in cities: does it have to be uniform?).

Angel and Blei tell us why bigger is usually better; in particular, bigger cities have bigger labour markets. When they examined a subset of 40 cities, they found that when the total number of jobs doubles, the number of jobs that commuters reach within a 60-minute commuting range increases on average by 97%.

The authors provide a concrete example. With 7.6 million jobs, New York was twice as large in 2000 as Chicago with 3.8 million. Yet workers in New York reached 6.2 million jobs within a 60-minute commute compared to 3.6 million in Chicago i.e. 85% more.

We must conclude therefore that the added friction created by the need to commute further and for a longer time in larger cities did compromise the size of their metropolitan labour markets but only to a very limited extent. The size of the metropolitan labour market – defined as the number of jobs that could be reached within a given time – almost doubled in cities with double the number of jobs or, more generally, with double the population.

This finding is consistent with what we already know; that commute times increase only modestly with population and are remarkably similar across cities irrespective of their size. Thus according to this league table, the average commute in Chicago is 30 minutes compared to 34.4 minutes in New York. Angel and Blei found commute times increase on average by just 7% when population doubles.

The researchers offer three key explanations:

  • While all cities spread further as they get larger, they also get a lot denser, making origins and destinations closer on average. When population doubles, the area of US cities increases on average by only 70%.
  • Investment in transport infrastructure increases as cities get larger (in the sample of US cities examined by Angel and Blei that’s mainly roads).
  • The most important factor, though, is that workers adapt to slowing commute times. Many stay put but many also change their home address to be closer to work and/or they change to a job that’s closer to home.

While it’s harder to do a lot about constraints like geography or incomes, cities can take steps to aid the adjustment process. For example, as they grow they could:

  • Improve mobility, by improving the efficiency of the transport system. That covers investment in new public and private transport infrastructure, as well as making better use of existing infrastructure e.g. via pricing.
  • Increase accessibility, by encouraging the redevelopment of established urban areas at higher employment and residential densities.
  • Facilitate adaptation, by reducing obstacles to households and firms relocating to new addresses e.g. by eliminating stamp duty liability on housing purchases (the stamp duty on a $1 million dwelling in Victoria is $55,000).

Accommodating population growth within cities makes at least as much sense as spending big on infrastructure like HSR to create sprawling dormitory suburbs in the regions. Growth is better viewed as an opportunity for our larger cities than as a problem.


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18 thoughts on “Will Sydney and Melbourne implode as they get bigger and bigger?

  1. Jacob HSR

    En Quiry #16,

    You will have to vote for the Sustainable Australia Party like me. Voting for the LNP/ALP will result in ongoing urban sprawl and environmental destruction.

  2. Dylan Nicholson

    En Quiry, growth internationally has already stop accelerating. But even if you were somehow able to stop all reproduction for the next 50 years the human race will continue to significantly increase its demands on the environment. And personally I don’t see that being lucky enough to be born in Australia (or to have moved here already) gives us a right to stop others wanting to come here.
    But speed of population growth is a very pertinent aspect to this post that I don’t think has been adequately dealt with. Did successful cities (or aggregate metropolitan areas) with a population over of 10 million or so today have to deal with a doubling over their size over 20 years or so? It’s hard to find reliable figures, but of the cities mentioned above, most seem to be more in the vicinity of 70-80 years doubling time, and strikingly, many have slowed down to the point that Cologne’s official population hasn’t really increased much since 1975, and Düsseldorf’s population has actually decreased markedly. Paris’s population shows a pattern closer to Melbourne or Sydney’s but still with a much slower doubling time. So even if it were somehow true that 12-13 million population is some sort of ‘sweet’ spot for a city, it certainly doesn’t follow that we shouldn’t worry at all about the possibility of either Melbourne or Sydney reaching that mark within, say, 60 years. Being able to manage growth that rapid is a very different challenge to dealing with the relatively moderate growth rate of cities with long-established histories. I’m not too worried about Australia having a population of 50 million by mid-century (it’s still remarkably few people for the area of arable land we have), but if more is not done to encourage growth of urban centres other than Sydney and Melbourne then I do have genuine concerns about what sort of places those cities will become.

  3. En Quiry

    Stop population growth accelerating. The environment can’t sustain it. The country has proved itself incapable of building the right infrastructure – beyond reasonable doubt. Australia will never create sophisticated high density because of absence of social control over development and the lack of a suitable urban culture. We do not need to create domestic markets because there are plenty of export markets.

  4. Alan Davies

    Dylan Nicholson #12:

    The only sensible way I can see to define the limits of a city is in terms of its connections, principally labour market. Where development stops, greenbelts, etc, don’t provide a useful definition. Labour markets is the basis on which the ABS now defines GCCSAs and I assume that’s the approach taken in the calculation of the metro area Dusseldorf is located within (perhaps it would be more palatable to refer to the Rhine-Ruhr metro area of which Dusseldorf is a component).

    Ian Brown #13:

    The City of Dusseldorf is not the metropolitan area, anymore than the City of Paris, City of New York, City of Brisbane, City of Sydney and City of Melbourne are entire metro areas. These are all local government administrative areas that are nestled within wider metro areas.

    For example, the City of Melbourne is a tiny 36 sq km (City of Sydney is 25 sq km) in an urbanised area of the same name that covers 2,500 sq km. The City of NY has a popln of circa 8 million but it’s within a metro area of circa 20 million.

    As indicated a number of times above, I got the 11 million metro number for Dusseldorf here.

  5. Ian Brown

    Dusseldorf population 11 million – are you having a laugh? See: http://www.amazingcapitals.com/dusseldorf/the-location/city-topics/facts

    To quote: “Some 600,000 people live in the city of Dusseldorf. The daytime population of the city increases on work days by over 200,000 when commuters pop in and out of the city. The closer agglomeration of Greater Dusseldorf reaches a count of two and a half million inhabitants, giving it roughly the size of Baltimore Metro, Seattle Metro or Greater Manchester.”

  6. Michael Williams

    I would like to see additional centres grow in Australia rather than limiting ourselves to the current de-facto policy of city or bush which also sets up political divisions. I can’t see why regional centres would be “dormitory suburbs”. The UK has fantastic secondary centres like Manchester, Glasgow, Edinburgh etc which add considerably to their appeal and commercial flexibility.

    I’m also concerned about the restricted water supply for cities like Sydney on a dry continent.

  7. Dylan Nicholson

    Alan, sure, and I’d suggest far far less than 5% of the residents of Bonn would commute to Dusseldorf – probably less than 1%! Bonn’s population isn’t that much more than Casey’s. But Bonn has its own “CBD” and headquarters for a large number of firms in its own right. I don’t know where I’d get figures for the number of actual jobs located in Bonn vs Casey but it’s a safe bet it’s far higher (Bonn is also an internationally recognized tourist destination, being the birth-place of Beethoven and all).
    The point is that jobs and residents of the Rhine-Ruhr area are spread in a very very pattern than in Melbourne or Sydney. I admit I’m making an assumption that this area has less traffic/transport issues that we do in Greater Melbourne, but maybe that’s not even true (as I mentioned, the cost of train travel in the is pretty horrendous). But I’d be surprised if the average commute distance was longer than here, and it certainly doesn’t “feel” like it’s a victim of an ever-sprawling metropolis (though it certainly has significant stretches of industrial development that aren’t exactly scenic).

  8. Woopwoop

    And what about the residents, or maybe owners, of inner city London? Granted many are non-white, but how many are non-rich,non-well connected etc? Few who actually work there can afford to live there.

  9. Teddy

    Well I’m off to the Ruhr next week, so all this discussion about what I’m about to see is all very interesting! If slightly off-topic…

    I’ve lived in Sydney (inner city suburbs) most of my life, but have spent extended periods in New York and a few years in London. And have hugely fond memories of those big cities (perhaps because then I was then childless!) Whatever, I have no fear whatsoever of an 8m Sydney or Melbourne. In fact I’ll look forward to (if I’m lucky enough to live that long). Whatever its problems will be, we’ll adapt.

    AJH #1’s post was fascinating though. In the inner ring suburbs of Sydney that same terror of high density and obsession with “villages” is like a religion. Any increase in densities is automatically opposed. Normally I’d single out the Greens as being the worst offenders (they are by far), but all the political parties and local community activist groups sing to same tune. To put it rather bluntly what they are saying is: “F— off, we’re full.”

    In NSW, we recently had a Premier (our worst ever) who (almost) used those exact words. In a case of severe relevance-deprivation syndrome, he’s still banging on about it .

    By London and New York standards, the densities in the inner ring suburbs of Sydney and Melbourne are not high. But the effect of the resident’s obsessions (and these people are usually rich, white, aging baby boomers who all drive, are well connected and have considerable political clout) is to force everyone else to car-dependent sprawl on the outskirts. Now that sort of 8m million Sydney or Melbourne is truly terrifying.

  10. Alan Davies

    dke #7:

    See the box on RHS of my link for Dusseldorf:

    • Urban 1,220,000
    • Metro 11,300,000 (Rhine-Ruhr)

  11. Jacob HSR

    Robots are about to kill 40% of jobs out there.

    So immigrants will stop coming here as they will not be able to get jobs.

  12. dke

    Hi Alan. I looked at your link. Dusseldorf pop 600k. The 13m figure is the entire Rhein-Ruhr region. Dusseldorf is a distinct medium-sized city within it. If only Australia could learn from Germany and create city boundaries instead of urban sprawl.

  13. Alan Davies

    Dylan Nicholson #4:

    I don’t doubt there may be people that live in Bonn and commute into central Dusseldorf but it would be nothing compared the number of people that live in, say, Berwick and commute into Melbourne CBD.

    You know that only around 5% of workers in the outer Melbourne municipality of Casey commute to the CBD, right?

  14. Dylan Nicholson

    In fact, wikipedia agrees with me exactly there – the Cologne metro area population is listed as 3.5 million.
    The “Rhine-Ruhr” metro area *includes* that entire area, as well as Dusseldorf, Essen and a number of significant cities in their own right.

  15. Dylan Nicholson

    But I wouldn’t really consider Dusseldorf/Koln/Bonn/Essen etc. as an ‘integrated labour market’. I don’t doubt there may be people that live in Bonn and commute into central Dusseldorf but it would be nothing compared the number of people that live in, say, Berwick and commute into Melbourne CBD. The transport patterns and living densities are very very different in that area to what we have in Melbourne and Sydney, which assume a single central area and a largely radial transport network with no other truly significant hubs. Check it out on Google Earth for some idea. But having traveled from Dusseldorf to Bonn and back (by train, which is exorbitantly expensive – in the realm of $50 for a return ticket, vs what would be a ~$7 ticket for travelling the same distance within greater Melbourne) I can assure you it’s truly stretching it to consider the latter to be part of Dusseldorf’s extended metropolitan area. I’d accept Bonn is more or absorbed into greater Cologne, and the Cologne metro area that would definitely constitute an integrated labour market probably would have a population not much less than Melbourne’s.

  16. Alan Davies

    Dylan Nicholson #2:

    As stated in the article it’s the figure for the Dusseldorf metro area – see here. That it includes well known and physically separate cities is beside the point (Melton is physically separate from mainland Melbourne!); what matters is the present extent of the single integrated labour market.

  17. Dylan Nicholson

    Um, where on earth do you get the 11 million figure for Düsseldorf (a city I could see myself living in at some point)?
    I’m guessing that’s for the Rhine-Ruhr metro area, but that includes several quite clearly defined large cities other than Düsseldorf (including Koln and Bonn!).
    My ideal “vision” for Australia in terms of settlement density would indeed be something not dissimilar to this particular area of Germany, where you have medium-high density smallish cities and villages of various villages separated by forest and farmland, but there’s much nothing like that here currently.

  18. AJH

    Small isn’t always beautiful.

    Some of the most unaffordable housing and longest commutes in the world are in Silicon Valley, which is sprawling, low-density and constantly cites a desire to “remain a village”.

    It is a “prestige” area for companies, and many large employers have campuses there (Google, Facebook, Apple, etc). Thousands of startups are also based there, as having a presence in Silicon Valley is almost a prerequisite for getting funding from many VCs.

    The heart of Silicon Valley (Santa Clara, Mountain View, Palo Alto, etc) has an intense aversion to high-rise development, which has led to absurd rents (US$3000/month for a tiny apartment not being unusual), and intense traffic congestion (a 10km commute can take an hour or more).

    During peak hours, the entire area may as well be a parking lot, as workers drive from satellite suburbs or surrounding cities like Oakland and San Jose. They may spend three or four hours per day in traffic, but at least they can afford their rent.

    The desire to keep the area “small” and an aversion to high-density living has basically ruined the place. A total lack of investment in public transport hasn’t helped.

    Had they compromised on their “village” ideal, and allowed some high-density residential development in select areas, then rents would not be as unaffordable, and traffic would not be as bad. Instead, they have created a sprawling mess with low living standards. It is not uncommon for three or four families to share a townhouse, just so they can afford to live within a reasonable commuting distance.

    The key to a growing city is higher-density residential development. Without it, you either hit constraints on growth and productivity, or you create a sprawling, unaffordable mess with intense traffic congestion.


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