The first exhibit shows the popular view of the geography of urban employment in Australia’s largest cities. It is commonly assumed the great bulk of jobs – and certainly virtually all “good” jobs – is located in the CBD.
This is an understandable view given the first exhibit shows the spatial distribution of employment density in Melbourne in 2006. It indicates the density of jobs in the Central Business District (CBD) – the first one km radius ring around the town hall – is an order of magnitude higher than anywhere else in the metropolitan area. It closely aligns with the cluster of high rise office buildings that define the CBD in the popular imagination.
But is this is an adequate representation of the geography of employment in Australia’s second largest city? The second exhibit highlights that density is not the same as the number of jobs. It shows how employment is really distributed within Melbourne – the CBD is easily the largest single concentration of employment, but it nevertheless has only 15% of all metropolitan jobs. In fact only 28% of metropolitan jobs are located in the inner city – i.e. lie within a 5 km radius of the town hall – and 50% are located within 13 km radius.
This dispersed pattern is not recent. Melbourne was compact and dense up until the end of the nineteenth century when the appearance of mechanised transport – primarily trams and trains – enabled middle class residents to escape the crowding and congestion of the centre for the space and amenity of the suburbs. This trend was boosted dramatically after WW2 when increasingly widespread car ownership democratised access to affordable land on the urban fringe.
Firms followed a similar pattern. Initially, manufacturing and distribution firms moved to the outer suburbs so they could escape congestion in the inner city, exploit new space-intensive horizontal production methods, and be closer to the suburbanising workforce. The suburban population generated increasing numbers of jobs to service its consumption needs, amplified by the increasing level of outsourcing from the home. More recently, some higher order activities have moved from the CBD to near-CBD and inner city locations and some back office functions have moved to the suburbs.
By 1981, only 35% of Melbourne’s jobs were located within 5 km of the centre. The “average job” was 12.4 km from the centre and the “centre of mass” of employment was 5.9 km away. The trend to the suburbs was very strong over the succeeding 25 years. By 2006 just 28% of jobs were within 5 km radius and the ‘average job’ was now 15.6 km from the centre. The centre of mass had moved 2 km further outwards to the vicinity of Tooronga, 7.9 km from the CBD. Read the rest of this entry »
We’re familiar enough with the idea of the ‘centre of gravity’ of population in Melbourne. But where is the centre of gravity of employment?
Is it the city centre? No, for one thing the CBD’s only got around 15% of all metropolitan jobs. For another, the combination of Melbourne’s distinctly lop-sided growth south of the Yarra and the fact that 72% of jobs are more than 5 km from the CBD, suggests it’s going to be somewhere south east of the CBD.
So I’ve calculated the location of the centre of gravity (more correctly, the ‘centre of mass’) of jobs from Census data. The accompanying chart shows how that location changed over the period from 1981 to 2006.
The centre of gravity is calculated by dividing Melbourne up into 1,000 traffic zones and weighting the coordinates of the centroid of each zone by the number of jobs it holds. If you imagine a relief model of employment in Melbourne, the centre of gravity is where you’d rest the model on a needle so that it balancess perfectly.
In 1981, the centre of mass of employment was 5.9 km east south east of the CBD, on Kooyong Rd, just north of Toorak Rd. By 2006 it was 7.9 km from the CBD, close to the corner of Malvern and Tooronga Rds.
This movement reflected the much stronger growth in jobs in the suburbs over this period compared to the CBD and inner city. Read the rest of this entry »
The accompanying chart shows how public transport’s share of the journey to work varies with population density across 41 US and Australian cities.
It is taken from the same article that I mentioned in my last post. The authors, Dr John Stone and Dr Paul Mees, find there is only a modest relationship between population density and transit share (R2 = 0.229). They conclude that “higher density across the whole urban region is not the explanatory variable that many might expect”.
Los Angeles, for example, is the densest metropolitan area in the US – denser ever than New York – yet the chart shows public transport’s share of work travel in LA is much smaller than in NY.
If that seems counter-intuitive, your intuition could be right. The chart uses average population density calculated across the entire urbanised area of each city.
While that’s perfectly alright in some contexts, it doesn’t allow for the possibility that public transport’s ability to win travel away from cars is related to the morphology of density – the ‘peaks and troughs’ in the way the population is spatially distributed. It’s possible that the relative proportion of population in high density areas vs low density areas has a greater impact on mode share.
Using average density probably won’t present a serious problem with cities like Atlanta, Austin, Dallas, Phoenix and Portland where the population is overwhelmingly suburbanised at relatively uniform (low) densities. But it could have a big impact on places like New York which have an extensive ring of low density suburbs as well as a high density central region e.g. Manhattan and Brooklyn.
A way of dealing with this issue is to use weighted density rather than average density. This involves weighting the density of each suburb (or other convenient geographical unit e.g. traffic zone) by its share of the city’s total population. So a one km2 suburb with 5,000 residents (say) carries a lot more weight than another suburb of the same area that has only 1,000 residents. Read the rest of this entry »
According to a report in The Age last month, new research published in the latest issue of Australian Planner shows that higher suburban densities are not a precondition for vastly better public transport. Reporter Andrew West says:
City dwellers have been presented with a false choice – live in apartments and enjoy good public transport or retain the house and land and rely on cars
The research by Dr John Stone and Dr Paul Mees contends that it is not necessary to intensify land-use across the whole city before significant improvement in both patronage and economic efficiency of public transport becomes possible.
They say the contribution made by urban consolidation “to recent public transport patronage growth is modest and makes little impact on the density of the whole urban region”. Most residents of Australian cities will continue to live in houses and suburban subdivisions that are already built so “alternatives to the car will need to be effective at existing urban residential densities”.
They argue instead for a ‘networked’ model of public transport. Improving the way existing public transport resources are managed – especially by providing higher frequencies and improving coordination between services and between modes – will yield significantly higher transit patronage in the suburbs without the need for broadbrush increases in density.
I’ve argued before that increasing residential density, by itself, will not necessarily increase public transport patronage significantly, much less shift travellers out of their cars in large numbers.
I’ve also argued that there are generally better gains to be had from using existing resources more efficiently rather than relying on strategies based around huge new infrastructure investments or massive land use changes.
And I think the idea of networking public transport is absolutely critical. By embracing transfers, networking provides faster travel paths to all parts of the metropolitan area than is possible by radial routing.
However it’s not obvious to me that ‘networked’ public transport, by itself, would have the sort of major impact on mode share in the suburbs implied by The Age’s report. I can see that it would make public transport much better for existing users and I’ve no doubt it would increase patronage, but I’m not persuaded that it would be enough to address the ‘false choice’ that The Age says Melburnites have been presented with. Read the rest of this entry »
Sooner rather than later, the Baillieu Government is going to have to prove its credibility on public transport by making substantial progress on one of the rail lines it has promised. And I have an idea for where it should start.
The easiest candidate is the promised Avalon rail line because its cost is estimated at only $250 million. But as some commentators have pointed out, including me, this would almost inevitably be a jumbo white elephant. It could be a real political liability too.
If good sense prevails, the Federal Government will refuse to contribute to the project and the Government will be off the hook. The private operator might also refuse to contribute to a properly designed financial model.
The other promised rail lines – to Rowville, Doncaster and Melbourne Airport – are all subject to studies. They will all be very costly to build to an acceptable standard but it’s unlikely the electorate will be bothered by the fine print or the cost. It’s likely that as far as they’re concerned, a ‘promise’ is a promise.
I’ve indicated before that none of these lines, on the face of it, seem ready for the green light just yet (here, here and here). Unless new information is introduced or the projects are redefined, it seems to me that any objective study would have to conclude they won’t be ready for funding for some time, probably not until after 2020 (it wouldn’t be politic for any government to come out and say ‘no’ outright).
But I think the Government will have to show serious progress on at least one of these lines by the time of the next election. In my view, the preferred candidate should be the Rowville line, but in an amended form. Read the rest of this entry »
The credibility of the six new suburban ‘supercentres’ announced by the Victorian Government in October 2008 has been undermined by a recent Government report on land supply.
The Government announced in October 2008 that it was upgrading six existing suburban Principal Activity Centres (PAC) to Central Activities District (CAD) status. The CADs are a new top-level category of centre intended to provide “significant CBD-type jobs and services” in the suburbs.
Described as “mini CBDs” by The Age and envisaged to have a mix of business, residential and civic uses, the six designated CADs are Broadmeadows, Box Hill, Dandenong, Footscray, Frankston and Ringwood.
I’ve previously pointed out there’s little evidence that any “science” was applied to the selection of the CADs. It seems the Government picked six centres under the existing Transit Cities Program and designated them as CADs.
They do not appear to be natural centres of commerce or industry. Only one of the six CADs (Box Hill) ranks among the nine largest suburban centres in terms of job numbers.
Now the 2009 Annual Report on the Urban Development Program issued earlier this year by the planning department shows that the CADs aren’t the preferred location of residents or developers, either. The accompanying graph indicates the number of dwellings recently built, under construction, or planned, in major suburban activity centres. Read the rest of this entry »
There are many misconceptions about the suburbs. A common one is that they are dormitories for workers who commute to the CBD. Another is that jobs in the suburbs are mostly low skill and low pay.
The reality is most economic activity in our capital cities takes place in the suburbs. In Melbourne, for example, 72% of jobs are more than 5 km from the CBD, 50% are more than 13 km away and 25% more than 22 km away.
Jobs have been moving away from the centre for a long time. The “centre of gravity” of jobs in Melbourne is now 7.9 km south east of the CBD, in the vicinity of Tooronga station, East Malvern. That’s up from 5.9 km in 1981. The “average” job is 15.6 km from the CBD (12.4 km in 1981).
This decentralised pattern holds for most industry sectors. More than 70% of jobs in the Community sector and more than 80% of jobs in the Retail, Wholesale and Manufacturing sectors are in the suburbs (defined as more than 5km from the CBD). Even in the Commercial Services sector, which is the inner city’s great strength, 49% of metropolitan jobs are in the suburbs.
Over 90% of Melburnites live in the suburbs and the great bulk work there too. Less than 10% of workers who live in outer suburbs like Casey, Cardinia, Dandenong, Knox, Maroondah, Mornington work in the centre (City of Melbourne). Even in older suburbs like Hobsons Bay, Brimbank, Maribyrnong and Moonee Valley, less than 25% of the workforce works in the centre. Read the rest of this entry »