Wednesday, December 11, 2013

Do density and public transport resolve congestion?

(First Published January 2013)

The compact city/transit answer to the urban sustainability question

Expensive – and usually loss-making – public transit is enjoying a resurgence in the face of uncertainty over the supply and price of oil, concerns about the proliferation of private vehicles and greenhouse gas emissions, and  questions over the sustainability of our cities.

Transit is generally promoted as part of a programme to increase city densities.  In Auckland, for example, the plan is to recreate a compact city in order to get people out of cars.  A commitment to increasing the capacity of rail-based public transport is intended to support residential densities and justify concentrating public investment in the CBD.
I have addressed some of the issues this raises in earlier blogs.   (E.g., Rethink the Link, Five More Reasons, Thin Edge of the Tunnel Wedge, Derailing Auckland)

Exploring the relationship – the data
Using the Tom Tom international congestion index it is possible to explore the association between congestion and city density.  I analysed Q2/2012 morning congestion figures for 25 North American and 51 European cities covered by the index.  The index is based on the real time experience of drivers in areas of high usage of Tom Tom car navigation systems.  Congestion is measured as the deviation in travel time on individual routes at peak times compared with when they are flowing freely (generally at night).  The higher the deviation, the greater the congestion.

I looked for relationships between morning peak hour congestion and city size, population, and density using the Demographia July 2012 compendium of world urban areas data.   

Here are some summary figures for the second quarter, 2012:
Source: Tom Tom, 2012; Demographia, 2012
Congestion is additional peak hour travel time compared with free flow travel over the same routes.
(Out of interest, the comparable density figures for Auckland, Hamilton, Wellington and Christchurch are 2,400. 2,200, 1,900, and 2,000 respectively). 

Note the greater range of congestion figures among European compared with North American cities, and their significantly higher high and median figures.
The North American evidence:  higher density = more congestion?
I undertook simple and multiple regressions in each case to establish how far differences in congestion depend on the physical size of cities, how far on their populations, and how far on residential densities.
Among the North American cities only population density was statistically significant, explaining 52% of the differences in morning congestion among cities.  By and large, as densities increase, so does congestion (Figure 1).  The inference is that transport efficiency is no better among more compact cities, and may be worse.

Figure 1: The relationship between density and congestion, North American Cities

Does transit help?
It would take more comprehensive evaluation to establish how far transit systems might modify this relationship between density and congestion. The US News website provides a ranking of the top ten US transit systems based on ridership, safety, and government spending.  Only five are in the Tom Tom sample. 

Figure 2 orders the cities from worst to best performing on the ground of the difference between congestion that would be expected on density grounds alone (as predicted by the regression equation in Figure 1) and the actual congestion recorded.  Hence, Boston has higher levels of congestion (48%) than predicted (27%) on the basis of its density (just 800 persons per square km). And like poorly performing Seattle, it has one of the top ten transit systems as ranked by US News (4th and 9th respectively).  

Figure 2: Congestion performance, North American cities

The other poor performers based on this analysis include both high density Montreal, Ottawa, and Vancouver, and low density Atlanta. 
This is not a definitive analysis.  Rather, it suggests propositions for further consideration.  Among these, higher densities do not necessarily mean less congestion – more likely the opposite.  And leading edge transit does not necessarily fix the problem. 

The European Evidence: there is no evidence
The results for European cities were completely different, adding weight to the argument that context matters: what works in one setting will not necessarily work in another.  Across the 52 cities there is no relationship between density and congestion.  (There is, however, a weak relationship with cities’ physical size, r2=0.25). 

Figure 3 plots morning congestion as a deviation from the median for the 51 cities and includes a plot of densities.  It isn’t easy to read. In summary, the poor performers are Warsaw (density 3,100), Marseilles (1,300), Istanbul (9,700), Toulouse (1,100), Rome (3,400) and Brussels (2,600).  The better performers include the smaller cities of Malmo (density 3,600), Zagreb (5,700), Valencia (3,000), Seville (5,600) and Bern (2,300).

Figure 3: Congestion Performance, European cities

Does transit help?
A listing of the world’s top ten transit systems in 2011 included only four from the European sample (and only the New York subway from North America).  The London Underground comes in third, but London Metro Area comes in at a low 39th on the European congestion rankings.  The Paris Metro is rated fifth , but Paris sits at 46th among the 51 European cities for congestion.  The Berlin U-Bahn sits at 9th place and the city's congestion 21st in Europe.  Copenhagen is 10th in the world transit stakes and 16th in congestion ranking.

While the results are quite different from the North American analysis, the European evidence also offers no grounds for suggesting that density is a prerequisite either to better commuting conditions or that congestion reflects the quality of transit systems.

(A contrarian might argue, of course, that transit creates a commitment to a land use pattern that promotes congestion, delaying or distorting the decentralisation of employment that might otherwise occur in a well-connected city). 

Pursuing poorly performing precedents
If nothing else, the analysis raises issues which deserve much closer analysis, especially in Auckland where they do not support plans for a high cost transit system to support a compact city.

While planning – and planners – in Auckland have a tendency to cite overseas precedent to support expanded rail-based transit and higher residential densities, the variability of overseas experience suggests that this is a highly risky strategy.  Context really does matter – not only here but also among the precedent cities our planners love to cite. This is especially the case when poor performers on the congestion scale like Vancouver and Seattle in North America and London and Paris in Europe are touted as paragons of integrated land use and transport planning. 

So why do our planners and politicians continue to gamble the city's fiscal future on an economically flawed project which overseas data suggests has limited prospect of meeting its objectives?       


Sunday, July 14, 2013

City of bites: urban design and eating in Auckland

The café culture in action
For some time now Auckland’s planners and politicians have been spending up on the central business district to attract people back to the city.  A major element of the CBD sell has been the attraction of a burgeoning café, bar, and restaurant culture. 

Well, as I said a year or so ago, it’s working:

The irony is that the new Queen Street reflects the inner city café and restaurant culture so extolled by those who promote central city revitalisation: Queen Street from Mayoral Drive north looks and smells a bit like a glorified food court, a strip of fast food joints, where inner city residents and visitors can wander up and down and grow fat.”

And now KFC wants to join the 42 fast food outlets counted by a Herald reporter on Queen Street, the heart of the CBD.  (This count excludes ethnic food shops - I have no idea what the moral or nutritional grounds were for this exclusion). 

Better design equals better eating??
How reassuring that Auckland Council is responding to this travesty of taste.  Its urban design champion Ludo Campbell-Reid said it would speak to KFC in an attempt to avoid ‘visual pollution’. 

Because evidently we’re not getting the eating culture that Mr Campbell-Reid expected or intended.  He says that there is still work to be done to see a “better mix of retail and healthy eateries”.  

"In the future, wouldn't it be amazing if there were restaurants in the middle of the street (and) the street was closed to the traffic in places? Wouldn't that be wonderful if people were able to sit outside and there would be high-end restaurants like the French Cafe, but also cheap and cheerful as well?"

Well good luck.  Let’s not let economics get in the way of good design; that way we can spend even more public money on urban design solutions to problems of public taste.

It’s all about demand and supply
It’s fine to take the nutritional high ground – and I empathise with obesity experts concerned that takeaways on Queen Street are contributing to growing waistlines. But that’s about personal taste and means, market offerings and messages, education, and perhaps even food regulation, but not urban design.  It’s about what individuals choose (and can afford) to eat.

Anyway, the proliferation of fast food cafes is not surprising.  The development of new, up-market precincts off Queen Street promoted by the Council to pander to middle class tastes has left something of a vacuum there.  Couple this with the restructuring of retailing and what is a poor Queen Street landlord to do?

Well, an obvious option is to lift yields on high value properties losing business to other precincts by intensification: subdividing and refurbishing ground floor space to increase rentals.  And it just so happens that fast food outlets (and trinket shops) can generally attract enough custom to carry the resulting small space rentals. 

And don’t forget that the Council supported this restructuring of Queens St retailing with a $43 million facelift aimed at making the street more pedestrian friendly.

And now they seem worried that it is not leading to the Auckland – or Aucklanders – that the designers evidently want.

But others seem to be more than happy with it – some lease the space out, others take up the leases, and yet others consume the goods.

Beer and burger, cocktails, coffee and desert
Coincidentally, there was a neat little advertisement placed in Canvas Magazine in the weekend Herald by “BIG Little City”.  This is the central city marketing campaign funded by Auckland's Downtown Business Association, Heart of the City.  Heart of the City is funded primarily by rates targeted on inner city properties.

The advertisement listed “191 reasons to love your city” (for city, read CBD).  It’s not a bad advertisement, and I have no problem with the BIG Little City campaign.

But here’s the interesting bit.  At least 98 of the reasons involve food or drink (or both), with plenty of pizzas, burgers, sweets and beers among them.  (The figure may be higher – I couldn’t quite work out some of the offerings).  The other reasons, incidentally, covered mainly movies and shows, beauty treatments and shopping. Nothing unique in that lot.

Selling the CBD – our very own city of bites
So how are we selling Auckland’s CBD?  Why, as a great place for a bite and a shake, or a beer.  And that’s exactly what Queen Street is offering.  It may not be to your personal taste, and it may not be particularly healthy.  But does that make the more expensive off-Queen Street bars and restaurants, their steaks, pork bellies, desserts, wines and liqueurs any more healthy or any less indulgent? 

Is that what defines Auckland?
So let’s not get too precious about our CBD.  Surely we don’t plan to design a city that excludes half the population? The 2006 Census showed that 48% of Aucklanders earned less than $30,000 a year.  (The median was $26,000). I doubt that many of them could afford the French café, or even cheap and cheerful restaurants offering al fresco dining in the middle of main street. 

And by the way, the 191 reasons to love our city apply to most largish cities in the world.  That’s okay – it’s good to remind Aucklanders, at least, that our city stacks up on measures of middle class living.  But it’s not going to sell Auckland to others.

An alternative vision
The 191 reasons aren’t going to make Auckland’s CBD stand out from the pack.  Perhaps a livelier, less indulgent, and more diverse downtown is called for (check out Wellington waterfront for an example).  Let’s have more action, assert our city of sails, indulge in our distinctive seascape and landscape, and acknowledge, embed, and celebrate our city’s Pacific and Polynesian heritage.  The real Auckland is a smorgasbord of places, people, and experiences, not just a smorgasbord.

So if we must get down to micro-planning (and I don’t think we should), let’s plan for urban spaces and amenities that are inclusive rather than aiming for a sanctuary of gentility remote from the real Auckland.

And let's recognise that cities, like eating, are a bit messy: and that we can't urban design them to order.


Monday, July 8, 2013

Cities Don’t Consume Resources, People Do

Urban form or urban consumers?
If we want to reduce the environmental impacts of modern society let’s prioritise consumption, not city form.  The evidence suggests that large cities (and especially city centres) are associated with a bigger environmental footprint than modest cities or suburbs. 

This post looks at incomes and consumption, especially the consumption of housing and transport services, asking how far can local regulation really influence environmental impacts?

What can local governments do about the environment?
Local governments have two core roles.  One is to ensure that the infrastructure and services necessary to sustain everyday life and commerce are in place and working well.  In fulfilling this role they should aim to enhance the quality of the urban environment and limit any environmental impacts of infrastructure. 

The other role is to plan and manage development in a way that reduces conflict among land uses.  In doing that they should aim to contain or control adverse spill-over impacts. 

However, for councils to use their investment in infrastructure and land use regulation to determine in detail how and where people should live and consume pushes the boundaries of these roles, particularly when they try indirectly to reshape household behaviour by reshaping the city.

The key to understanding the environmental impacts of urbanised society is not urban form but household consumption, a function of income, not city plans.

Urbanisation and environmental impacts
In my last blog I showed how policies to increase residential densities around city and town centres assume a relationship between urban form and environmental impacts that is not supported by the evidence . In Australia, for example, residents of the New South Wales state capital, Sydney, particularly central Sydney, have by far the largest environmental impact per head.  Much lower levels are recorded in suburbs, smaller cities, and towns. (The same pattern is evident in all Australian states: have a look using the Australian Consumption Atlas).

The environmental impacts of intensive urban living outweigh any advantages of increasing scale and density. This means that policies that push agglomeration and intensification will increase rather than lower the impacts of urban living.

Household spending is the issue
The Australian study confirms that a city’s environmental impacts simply comprise the collective impacts of its residents.  Income is the driver of their consumption and thereby their demands on the environment. 
If we really believe city form can in some way over-ride income- and consumption-driven environmental impacts, then we should heed the evidence, and plan for modest, small scale, dispersed urban settlement. 

Spending on housing and transport in New Zealand
Household Expenditure Survey data for New Zealand (and elsewhere) provide an opportunity to explore the role of income in consumption generally. 

First, take a look at the distribution of spending on housing, transport, and discretionary goods (recreation and cultural services is used to represent the latter category) according to household incomes in 2010. Average spending levels have been organised by income decile for this purpose, each group containing 10% of households. Average incomes increase from decile 1 (the lowest earning 10% of households) to decile 10 (the highest earning 10%).

The pattern is pretty predictable.  Housing dominates the spending of low decile households.  It accounts for 34% in the lowest decile, falling to 22% in the ninth.  It rises again (to 24%) in the highest earning decile (10). This lift between decile 9 and 10 households no doubt reflects higher discretionary spending in the latter group by way of additional space, the quality of fit-outs, and second homes. 

Shares of Household Spending to Selected Categories, by Income Band
Do lower housing costs lead to higher transport spending?
Rent theory suggests that lower household spending is offset by higher transport spending.  This is because low income households can only afford cheaper, less accessible properties and so end up commuting further at a higher cost than high income households. 
It turns out that it’s not that simple.  Contrary to the theory, higher income households actually spend more of their income on transport.  That makes sense when we realise that commuting accounts for only around 25% of time spent travelling by New Zealanders.  The capacity to take discretionary trips is a bigger determinant of transport consumption than non-discretionary commuting and work-based trips.

The Relationship Between Spending on Housing and Transport

Lower incomes leave a lot less to spend on discretionary goods and services once housing and essential transport spending are covered.[1] Higher income households can and do travel more and consume more.  Their behaviour is unlikely to be significantly influenced by changing city form.  

Who spends how much?
Not surprisingly total consumption in New Zealand is dominated by higher income households: the 20% highest earning households (deciles 9 and 10) account for 35% of total spending on goods and services, while the lowest earning 20% (deciles 1 and 2) account for just 20%.

And decile 10 households account for 7 times more spending on transport than decile 1 households.  They spend 5.5 times more on recreation and cultural services, and 3.5 times as much on food.
The Contribution of Household Total Expenditure by Income Band, Selected Categories

The highest income households spend three times more on housing than low income households, an average of $476 per week compared with $161.
If refurbished housing in high amenity inner city living is expensive, guess which income groups will be living there?  The high consumers, obviously.  And in Auckland, at least, it seems that city planners and policy-makers are keen to deliver them the high order consumer services that will promote ever-more discretionary spending around the CBD(although much of central city resident travel may be taken up with recreational and social trip-making away from there).   

A high social cost for little environmental benefit?
The conclusion is straightforward: higher incomes mean more expenditure on additional housing, transport, and discretionary goods and services with correspondingly high environmental impacts.  If incomes are higher in cities, then their collective impacts will be high too. 

Planning policies won't change that much - except to the extent that they erode consumption by inflating the basic costs of living, something that impacts most heavily on lower income households.  

Fiddling with city form is unlikely to significantly reduce the impact of higher incomes and associated spending on the environment.  Increasing dwelling and living costs by promoting larger cities, higher residential densities, and uneconomic transit systems simply penalises low income households already committing substantial shares of their spending to housing and transport.  And this is the group that, by dint of constrained consumption, has the lowest impact on the environment. 

Better to address environment issues directly
From a policy perspective, environmental issues are better tackled directly.  This may mean promoting environmentally friendly goods and services, promoting low impact technologies (including low impact housing, fuel efficient vehicles, and the like), and encouraging responsible consumption. If we are really serious about environmental threats, we need to examine the efficiency of current pricing practices and even taxation measures, rather than leaning so heavily on clumsy, indirect, and ultimately spurious urban planning policies. 

[1]           Overseas spending is omitted from discretionary spending here as it is included in the catch-all category “Other Expenditure", which accounts for 6% of decile 1 spending and 11% of decile 10.

Wednesday, June 26, 2013

Cities and Sustainability: Is Intensification Good Policy?

Evidence on urbanisation and conservation from New South Wales ...

Squeezing up to save the environment
This post examines the idea that we can promote sustainability by increasing the densities of large cities around their centres.  This compact city paradigm presumes that we can reshape the consumption of citizens in environmentally benign ways by reshaping the cities they live in. 

The sustainability challenge is the challenge of consumption: how much and what we consume drives our impact on the planet.  But presuming that by enforcing urban intensification we will transform ingrained patterns of consumption in favour of the environment may be a step too far.  Will obliging more citizens to live at higher densities in smaller dwellings around city centres really pave the way to environmental salvation?

Some evidence of urban impacts
The Australian Conservation Foundation is committed to ecological sustainability, tackling the social and economic causes of environmental problems.  Among other things, the Foundation publishes the online Australian Consumption Atlas. This is a useful source for addressing the role of urbanisation and urban form.

The Atlas is based on methodology which traces the direct and indirect demands on the environment of different goods and services.  Consumption patterns from Household Expenditure Surveys are related to household size and type, members’ age structure, incomes and education, and the statistical areas they live in. Using this information the environmental impacts of individuals living in different areas can be mapped. 

Three indicators of impact are displayed in the atlas: tonnes of greenhouse gas emitted, litres of water consumed, and ecological footprint.  The latter estimates the area of resources required to support a person’s lifestyle.  You can read more about the methodology here.

The data underlying the atlas is dated – based on the 2001 Census and 1999 Household Expenditure Survey, among other things.  But I do not expect the relativities it demonstrates, or the conclusions it supports, to have changed much.

Cities don’t consume; people do
Here is the authors' key conclusion. Our urban planners, designers, and politicians should consider carefully:

despite the lower environmental impacts associated with less car use, inner city households outstrip the rest of Australia in every other category of consumption. Even in the area of housing, the opportunities for relatively efficient, compact living appear to be overwhelmed by the energy and water demands of modern urban living, such as air conditioning, spa baths, down lighting and luxury electronics and appliances, as well as by a higher proportion of individuals living alone or in small households.

In each state and territory, the centre of the capital city is the area with the highest environmental impacts, followed by the inner suburban areas. Rural and regional areas tend to have noticeably lower levels of consumption.
(Consuming Australia: Main Findings, 2007, Australian Conservation Foundation, p.10)

Looking inside Sydney
I explored the indicators for different parts of Sydney.  Here are some results.

Indicators of Environmental Impacts: Sydney Centre and Suburbs
People in Inner Sydney generate 92% more greenhouse gas than the New South Wales Average, and well over twice as much as people in the lower income western suburbs, like Penrith and Blacktown. The levels are a bit higher for people in the more prosperous northern suburbs. Despite proximity to major employment centres, and an efficient commuter rail service, the consumption patterns of Willoughby and Ku-ring-gai residents generate high levels of air pollution.

Looking East to Sydney CBD
A similar pattern is evident for water consumption – residents of the hot, dry, western suburbs account for the least consumption, Inner and North Sydney residents the most.  They also have the biggest ecological footprint.


So what does this tell us?
The lesson is not necessarily that location in the CBD is less sustainable; but that the lifestyle associated with it is.

I have discussed the potential inefficiency of small, multi-unit dwellings elsewhere.  Over and above that, the high cost of redevelopment in central locations calls for housing construction strategies that add little to sustainability. 

One strategy is to build to modest standards.  This keeps the price down and rental yield up for investors; or creates opportunities for ownership by low income earners.  Another strategy is to adopt high standards of fit-out and install luxury appliances in favoured locations to make multi-unit dwellings attractive to wealthier households. 

Neither option is particularly environmentally sympathetic. 

Smaller is still better
I also reviewed the indicators for smaller cities and towns in New South Wales.  (In some cases these included surrounding rural settlement). 

Indicators of Environmental Impacts: New South Wales Towns and Small Cities

This suggests that smaller towns hold the key to environmentally sustainable lifestyles, even more than city suburbs.  For example,  Coffs Harbour's 73,000 residents generate greenhouse emissions at 88% of the state average, and just 46% of inner Sydney residents.  They consume water at 81% of the State rate (and 60% of North Sydney), and have an ecological footprint just 60% of their inner Sydney counterparts.  Similar patterns are evident in coastal settlements like Byron Bay (33,000 residents), Ballina (42,000), and Port Macquarie (77,000) and inland towns such as Griffith (26,000), Tamworth (60,000), and Wagga Wagga (64,000).

What does it all add up to?
A simple overview can be derived by summing the percentage deviations of each area from the New South Wales average across the three measures. Admittedly this is a course approach: it weights each indicator equally, and ignores differences in how much centres vary across each individually.  Nevertheless, it provides a sufficiently meaningful overview to confirm that towns and small cities are generally more sustainable than a large city, and that the suburbs perform better than the inner city.

Summary Index of the Environmental Impact of Urbanisation
Explaining the sustainability dividend of small towns
There can be any number of explanations for this, the obvious one being that it is all about income.  Perhaps the advantages of lifestyles outside Sydney simply reflect lower average incomes in smaller cities and towns.  As people become more affluent or seek more income, they migrate into the main cities taking their high consumption expectations with them; or by living in large cities they are more likely to earn - and consume - more.

Conversely, living in smaller cities and settlements may reflect lifestyle preferences which are intrinsically less environmentally intrusive.  At the same time. small settlements make less travel demands given the greater proximity to work, shopping, service, and recreation opportunities.  In addition, lower density housing may provide more opportunities for passive energy efficiency, directly reducing resource consumption for comparable activities.  

Flawed policy
Until we know more, however, we need to avoid the trap of determinism.  It would be short-sighted simply to invert the current paradigm, for example, and decide that policies to encourage people to live outside large cities and city centres will somehow enhance sustainability.

Ultimately, how we live is more important than where we live.  What the evidence here confirms, though, is that under current patterns of consumption promoting large scale urban consolidation is flawed as environmental as well as urban policy.