Uber in London article available for download

A paper on the introduction and regulation of Uber in London led by Geoff Dudley, with David Banister and myself as co-authors, is now published in The Political Quarterly. It is available for free download until mid-June. You can find the paper here. The article discusses the challenges that Uber’s disruptive innovation strategy has brought to various stakeholders in London, particularly taxi operators and TfL. It also discusses the prospects of Uber’s disruptive innovation strategy now the company is rapidly becoming an established player.

The paper is part of a research project on the governance of urban mobility transitions which focuses on Uber in London as a case.

Cities and Transition towards Low Energy Mobility

The first paper from my research on Innovations in Urban Transport has recently been published in the open access journal Sustainability. It summarises some of the analyses on the emergence and early development of low energy innovations in the everyday mobility of two UK cities, Brighton and Oxford. In many ways these cities are ahead of the curve in transitioning towards urban mobility systems characterised by lower energy consumption and greater energy efficiency compared to systems that are strongly dominated by private car use. And the empirical analysis confirms that many innovations related to cycling, bus and rail transport, shared mobility and clean cars are developing in both cities.

The paper argues that geography matters to transition processes in various ways. Innovation trajectories with regard to low energy mobility are differentiated geographically: where Oxford has a stronger orientation towards electric mobility (hybrid buses, electric vehicle charging, a car club with electric vehicles), Brighton tends to stand out in its attempts to create a cycling friendly infrastructure and the rapid expansion of car clubs. But the analysis also shows that cities should not be seen as independent and discrete spatial units in which innovation processes unfold. This is because most of the financial resources for those innovations come from elsewhere, notably the national government but also the EU. Thus, like technology and expertise do (as the literature on policy mobilities suggests), the finance of innovations in low energy mobility ties cities into wider uneven and networked constellations that encompass cities, states and EU institutions.

From this perspective, the budget cuts that local authorities across the UK will be experiencing due to changes to national level policy are not good news: they are likely to threaten the much needed continuity in support — finance, expertise, officers’ social capital, etc. — for innovations in low energy mobility in the early stages of their development. Indeed, a discourse of localism cannot prevent that significant reductions in national funding for local transport are likely to slow down of the rate change towards lower energy consumption in everyday mobility in many UK cities.

Do Bike Sharing Schemes Reduce Energy Consumption?

Even though they have been around for some 50 years, bike sharing schemes (BSSs) have in recent years witnessed a dramatic growth in cities in the UK, elsewhere in Europe, North America, East Asia and to some extent Latin America and Australia (for overview of the current spatial distribution, see  http://bikes.oobrien.com/global.php and  http://bike-sharing.blogspot.co.uk). Recent schemes differ enormously in terms of size, governance and business models. Compare, for instance, Hangzhou‘s mammoth scheme which is initiated, provided and run by the local state with Oxford‘s recent BSS experiment with 30 bikes and 6 docking stations that has been initiated by the county council but provided and run by a private company.

Intuition would suggest that BSS help to reduce energy consumption in urban transport, but I don’t think we really know much about their energy implications, for various reasons. First, on top of the existing diversity in schemes, the growth in both the number of schemes and size of individual schemes means that the social practices in which shared bikes are enrolled and hence the energy implications are diversifying rapidly. This increases uncertainty about energy implications. Second, there is a lack of appropriate data. This claim may appear counterintuitive given that most 3G and 4G schemes are hailed for the unique data they generate. But these data suffer from similar limitations as many other ‘big data’ on transport in being extensive but also thin on actual content. They either show which bikes are docked at (many) specific moments at particular stations, or where in physical space a given bike is at particular times. At best, we can reconstruct high-resolution space-time trajectories of individual bikes, but learn little about how bikes become coupled to and enrolled in the space-time paths (time-geography) and activity/travel patterns (activity-based travel behaviour analysis) of individuals, or in social practices (practice theory). Neither do we currently know much about how the space-time trajectories of shared bikes are related to those of other, motorised modes of transport. Consequently, as far as I am aware, there is little or no robust evidence that BSS usage actually substitutes for more energy-intensive ways of moving around the city, or about the extent to which schemes generate new demand for mobility. The nascent, and often rather celebratory, academic literature on BSS usage tends to examine trip patterns in isolation from wider urban transport systems. What is known on substitution comes either from modelling studies, in which all kinds of often strong assumptions about modal choice and substitution are made, or from studies using questionnaires with general questions about mode use that often lack the required precision, validity and reliability.

That said, there are good reasons why BSSs might help reduce energy consumption. Not only are the embedded energy and greenhouse gas emissions likely to be much lower for a BSS than for a bus, light rail or car system of the same spatial extension (a life cycle analysis examining this conjecture would be useful!);  by reducing the ‘last mile’ problem of ‘egress’ transport from a public transport stop to one’s final destination, a BSS can – if integrated adequately into a multimodal transport system – increase the attractiveness of public transport for people who might otherwise be using a private vehicle. BSS usage in a city context also generates all kinds of indirect effects, which might even exceed direct modal substitution effects. Use of shared bikes for utilitarian trips, for instance by people commuting into London by train seeking to reach their final destination, may increase those people’s inclination to cycle in other situations, for instance around the home for non-work trips. Widespread use of shared bikes in cities may also increase skills and competency among a range of road users: cyclists may begin to feel more confident in using bikes in other contexts, including those where conditions (infrastructure, actions of other road users) are less conducive to cycling, and drivers of cars and goods vehicles become more attuned to sharing the road with cyclists, possibly to the extent that subconsciously reckoning with cycling at left turns and other risk traffic situations becomes second nature. This reasoning obviously is a variant of the more widely known ‘safety in numbers‘ argument.

The question of energy consumption should not only be looked at through a lens of instrumental rationality and effectiveness; issues of social justice should be considered as well. Few studies have so far examined the social distribution of benefits, but the limited work that is available suggests that white, middle-class men are most likely to regularly use a BSS (e.g. Goodman and Cheshire 2014). It would appear that BSSs do little to address inequalities in access to transport that exist in most cities. Perhaps this is not surprising if the proactive approach of many local governments regarding BSS is placed in a wider context of urban entrepreneurialism and government-led, pro-growth oriented gentrification and regeneration. Having a BSS in a city is then not merely about environmental or social sustainability (air quality, GHG emissions, redistribution) but – and perhaps primarily – about creating an environment capable of attracting the mobile capital of firms, tourists and prospective residents by offering a transport scheme that is both fast and congestion-free, and fashionable and fun. There are also opportunity costs: pouring public money into a BSS probably means that less funds are available for more socio-spatially inclusive initiatives that can promote cycling as an energy-efficient means of urban mobility, such as bike co-ops, maintenance workshops or cycling competency training. Community-led, grassroots initiatives should not be romanticised and many in UK cities are to some extent supported by councils, but it would appear that these activities have greater potential than BSSs to reach migrant communities, the elderly and the urban poor and thus to link energy efficiency aims with progressive public health and social agendas.

BSSs have potential to reduce energy consumption in urban transport, if adequately integrated in a wider multi-modal transport system and as long as they do not constitute the mainstay of cycling policy and local governments’ financial support for cycling. It is a cliché to say that more research is needed, but we really need to know much more about how BSS usage is shaping and shaped by social practices in the city, what its energy implications are, and how BSSs link in with pro-growth agendas that do little to redress the soaring inequalities in mobility, life chances and health in contemporary British cities.

The financial viability of public bicycle hiring schemes

At the Journal of Transport Geography we are currently preparing a special section on the spatial analysis of public bicycle hiring schemes. The section will be guest edited by Jonathan Corcoran at the University of Queensland, Australia and Teibei (Terry) Li at Griffith University, Australia and is due to be published later this year.

The section will make a useful contribution to the now burgeoning literature on bike sharing schemes in transport studies and geography. Many of the recent studies are fairly positive about the potential of these schemes to expand and help making urban transport more sustainable. But there are some more critical voices as well, and my attention was drawn to a recent piece by Matthew Christensen and Susan Shaheen — a leading researcher when it comes to the sharing of bikes and cars.

Their argument is that the financial future of many of urban bike sharing schemes are not as bright as some of the celebratory accounts of bike sharing suggest. This is partly because corporate sponsors may be quite interested in supporting schemes in the start up phase but less so in keeping established schemes running (as is currently happening in London). Furthermore, at the current time of financial austerity at the local level across large swaths of the Global North, the local state may not be very willing to keep bike sharing system with ailing finances afloat. On the other hand, there is the question whether local governments really have a choice: when push comes to shove, will they really withdraw support for schemes whose start up has attracted lots of attention in the (local) media? As often in transport governance, political discourse and reality may go their separate ways.

A series of risks can nonetheless be identified. If it turns out that ailing systems will indeed be kept running with public subsidy, we will see that local governments — keen to follow ‘best practice’ and set up their own bike sharing scheme — have locked themselves into (financially) supporting another public transport system in an era when extra funds for transprt policy are unlikely to become available (at least in the Global North). Given that public bicycle sharing system are often socially selective — they are often patronized much less by poorer households, migrants from non-western backgrounds, women — ethical questions regarding justice in the city will be raised as well.

Slack time?

It has been a while since I last wrote on this blog, but that doesn’t mean I have been idle over the past two months. I have just returned from a visit to Chile and more specifically the University of Concepcion, where I have worked with our great host Juan-Antonio Carrasco as well as Karen Lucas and colleagues from Ghent and Concepcion on a collaborative project about the relationships between social exclusion and transport disadvantage in different geographical contexts. This three-year project — funded by the EU’s Marie Curie programme – has been under way for quite a while now, but our visit to Concepcion has been important in taking the project to a new level. I am really excited about the empirical work with data from Chile and Belgium (and the UK at a later stage) that we have set out to undertake.

Since June the Research Centre on Innovation and Energy Demand, in which the Universities of Sussex, Manchester and Oxford collaborate and which is funded by the UK research councils (primarily the EPSRC), has officially been in existence. We are currently in the starting-up phase and our website is still under construction. However, a summary of what the Centre is about is available here. As part of the Centre we are currently developing a project about what drives the emergence and success of low-energy initiatives in energy consumption reduction in urban transport, in which we will be comparing different city-regions in the UK: Greater London, Merseyside (Liverpool), Brighton and Hove, and Oxford. The idea of the project is to more fully integrate understandings of niche developments in sociotechical transitions thinking in innovation studies with thinking on the role of space and place from economic, urban and cultural geography.

There is no doubt I will report on the development of the project and the Centre on this blog in the (near) future!

Moving towards low carbon mobility

Moving Towards Low Carbon Mobility

A few weeks ago the Moving towards Low Carbon Mobility book edited by Moshe Givoni and David Banister came out. This is a book with chapters written by researchers of the Transport Studies Unit on different dimensions of low-carbon mobility, including technology, governance, infrastructure finance and pathways to a low-carbon future.

My contribution to the book consists of a chapter that reviews the latest thinking on socio-technical transitions in transport. It covers key theories — the multi-level perspective advanced by Frank Geels and others, social practice theories advocated by Elizabeth Shove and colleagues and the complex systems approach that John Urry has elaborated over the past decade — and seeks to outline how these strands of social science research can inform thinking about how to effectuate the step change towards low carbon transport.

I have also contributed to the final chapter of the book on how transport policy should be reconfigured for a low-carbon transport future to become a more realistic prospect. Here Moshe, David, James Macmillan and myself argue that what I tend to call the ‘logic of provision’ — the idea that providing alternative, better, speedier, more fashionable, etc infrastructure is the primary means for bring about change in the transport system — and prevailing understandings of travel time as a cost to be minimised are more of a hindrance to step change than that they will really help to bring a transition about. We also begin to outline a list of guiding principles for alternative transport policy but it must be said that this is only the beginning. Much more thought needs to go into answering the question what policies should look like if they are to help to bring about fundamental change in transport.

Rethinking behaviour change with Dewey

The annual meeting of the Association of American Geographers ended two weeks ago but I have not been able to write about my experiences during the conference so far. This post will address the presentation I gave at the conference, where I was part of a very interesting panel on what pragmatism — the philosophical movement that emerged from the work of RW Emerson, CS Peirce, W James and J Dewey around the turn of the 20th century in the USA — has to contribute to contemporary human geography. I gave a paper on how the work of Dewey (and James) on habits can be used to rethinking existing conceptualisations of behaviour change in academia and policy with regard to mobility, energy consumption and in other domains.

The thrust of my argument was that Dewey in Human Nature and Conduct (1922) offers a useful perspective on behaviour change that can function as a corrective for prevailing conceptualisations in behavioural economics, social and behavioural psychology, and thinking on habits in sociology and geography. This is because Dewey strikes, perhaps more successfully than other thinkers, a genuine balance between body and mind: he refrains from privileging one over the other and avoids the risk of making too much (economics, psychology) or too little (non-representational thinking in geography) of reflective thought.

More specifically, Human Nature and Conduct understands habits as forceful predispositions to act and interact with one’s environment, and not as actual behaviour. As such habits are socially constructed, ecological (they are not attributes of an individual but distributed across individual and environment) and generative. For Dewey repetition is not the essence of habits; what is important is that they propel individuals into action. The key distinction is not between habit and (reflective) thought, but between routine habits and intelligent habits. Both entail mechanism but in quite different ways. Routine habits reflect the often inert and maladapted mechanism of the ‘mere technician’; it amounts to ‘enslavement to old ruts’. In contrast, intelligent habits  amount to the mechanisms of the artist which are infused with thought and feeling and which afford mastery of emergent conditions; the archetypal example would be the piano virtuoso. The implications of this way of thinking are that  habit and reflective thought are non-exclusive of each other, and that thought itself is habitual.

Dewey also offers an interesting perspective on how habits and thought emerge. Discussing this is beyond the scope of this post but suffice to say that, on a Deweyian view, an always changing configuration of habits allow people to move through the situations of everyday life in a more or less unthinking manner. However, the working of those configurations can be disrupted by problems thrown up by the ‘on-flow’ of situations of which individuals as bundles of habit become part. Habits of movement , for instance, are impeded when suddenly confronted with a forked road. It is at such moments that, triggered by ‘impulse’ or instinctive and biologically driven action, emotions surge and reflective thought (as a function of mental habits) emerges in a person. So, as in recent perspectives in the life sciences, the philosophies of AN Whitehead and M Merleau-Ponty and contemporary social theories of affect, reflective thought is not primordial to action but a consequence of how individuals interact with their environment.

The point of reflective thought, for Dewey, is to transform (disrupted) action, impulse and emotions into a new course of action and so create a new meta-stable equilibrium between individual and his/her environment. This may imply that previously created habits need to be updated or revised. And for Dewey the role of reflective thought in habit change is crucial as it alone makes durable change possible. Impulse and emotion are crucially important to behaviour change but their surge wears off over time in ways that does not (always) happen with reflective thought. At the same time, Dewey was adamant that emotion and thought are continuous. They are not to be thought of in dualistic terms, but as mutually reinforcing: thought powered by feeling is likely to be more effective in bringing about change.

What does all of this mean for thinking about behaviour change with regard to mobility and energy consumption? I believe there are two key lessons here. One pertains to education — a topic on which Dewey has written extensively throughout his academic career and for which he is arguably most well known; the other to change of the environment which gets incorporated in habits.

Dewey was clear that changes to the ‘objective environment’ were the only way to influence habit formation through policy and governance. On the face of it, this reasoning appears to support such initiatives as New Urbanism or road pricing policies to trigger behaviour change in everyday mobility. However, a Deweyian perspective moves us beyond  this. It is not enough to increase densities, walkability and public transport accessibility in general; the challenge is to start from the situations of ongoing activity: what were people doing before taking a trip? where do they want to go? what/whom do they need to travel with? etcetera. This means that the lessons from activity-based approaches to passenger transport and time-geography need to be taken serious and to the extreme. The focus should really be on how each individual trip is embedded in the lived experience of everyday life and on all the problematisations (where problem is defined in the Deweyian sense outlined above) one may encounter along the way.

With regard to education, a Deweyian perspective foregrounds the importance of helping the younger generations — society’s future — to learn mental habits and habits of overt action that differ from ours. They, first of all, need to develop the skills to low-carbon mobility. So cycling training where children learn-by-doing how to navigate complex traffic situations should be a key part of primary education across the Global North: today’s practical skills are tomorrow’s mental habits. All generations — but especially the younger for whom mental habits are easier to change — should also be stimulated to develop new mental habits. Educating them about the ‘unfreedoms’ and socio-environmental costs of automobiles would be one part of this; another would be to learn them to resist to think in silo’s about energy use. This would hopefully prevent the pattern of what behavioural economists call mental accounting and that can be observed in many users of transport systems (myself included) who walk and cycle extensively to access everyday activities and hence consider themselves to be environmentally conscious but who also treat themselves to one or more long-distance trips by airplane for holiday or leisure purposes and so increase their emissions of greenhouse gases far beyond those of people who use the car much more often and only make short-distance holiday and leisure trips by surface modes of transport. Clearly, then, the forms of education that can be derived from a Deweyian perspective on habit and behaviour change are quite different from the social marketing and attitude oriented approaches that would result from a behavioural psychology account.

Exploring all details of Dewey’s account of habits is beyond this post, and the same applies to all the lessons for policy and governance. However, I hope to have made clear that a Deweyian vision can usually complement existing thinking on behaviour change. I am sure I will be writing more on this theme in the future.

Peak car travel?

A topic that is currently attracting considerable attention in transport studies is the slowing down or even decline in the growth of car use across the Global North. The car evidently remains the the dominant mode of transport for everyday activities, but among young adults – and especially young men – holding a driver’s license, car ownership and the per capita distance by car have been decreasing since 1990 or thereabout. This trend has been attributed to a range of factors (see, for instance, Newman and Kenworthy 2012):

  • a revival of public transport in urban areas
  • a slowing down of the pace of urban sprawl
  • (re)emerging cultures of urbanism, implying among others that more younger adults than before remain in the city rather than relocate to the suburbs
  • population ageing
  • the rise in fuel prices since 2000
  • the economic crisis followng the 2007/07 credit crunch
  • the waning influence of the car industry and lobby on public attitudes towards transport
  • possibility that growing number of car users now spend so much time in their cars  that they are unwilling to drive even more

It is beyond doubt that automobility — the practices, institutions and landscapes centred on the private car — is changing in countries like the UK, Germany, Japan and even the USA. But it is far too early to read the end of the car’s dominance into these developments. For one, a stabilising of the growth in car use and ownership is just that: it does not mean that as yet there are fewer people who are actually using or owning a car. And it remains to be seen what the future brings: it is not unlikely that the growth of car use and car ownership picks up again in the near future, for instance when the capitalist economies of the Global North enter a new growth cycle.

More significant, however, is that automobility has gone global over the past decades. At the global scale automobility continues to expand rapidly — think of the rapid growth in China, India, Brazil, Mexico, Indonesia, Ghana, Nigeria, etc. We could therefore say that the global system of automobility is in great ‘health’, however undesirable that is from the point of view of environmental degradation, CO2 emissions and social justice. Peak car travel in the Global North is a significant development at the national level but it is also dwarfed at the global level by the developments in the Global South. A narrow focus on the developments in car use in the Global North is therefore a variant of western-centric thinking.

One might argue that the developments in the Global North are still significant as they are countries like Japan or Germany are the front runners and that the patters observed there will eventually be replicated in places that now experience rapid growth in car use. This argument, however, is developmentalist: it assumes that there is a more or less universal development trajectory that all countries will ultimately follow — a form of thinking that is not only Western-centric (as it positions Europe, the USA and Japan as leading by example) but also sidelines the role of spatial multiplicity (see Doreen Massey’s book For Space for further elaboration of this argument).

Peak car travel is a significant development but it must be placed in perspective: it is ultimately a local phenomenon that hardly dampens the global growth of car use. This means that transport’s contribution to global warming remains enormous and that there is no time for complacency: it remains absolutely critical that transport planners and professionals think more seriously and creatively about how step changes away from automobility can be realised. Conventional policies (investment in new public transport infrastructure, urban compaction, mobility management, road pricing) may have facilitated peak car travel in the Global North — though their effects should not be exaggerated as these policies’ public acceptability is partly a result of the same cultural, social and demographic changes that made peak car travel possible — but they appear quite inadequate at fundamentally reducing the growth of automobility across the Global South.

On the Rational and the Emotional in Transport Analysis

Yesterday a PhD student posted a series of questions regarding the analysis of the choice of acquiring and using a car on the mailing list of the UTSG (universities’ transport studies group). He had spoken with experts in marketing and psychology who claimed (a) that this choice is both rational (travel utility – price, time, etc) and emotive (symbolism of a brand for an individual and their self image), and (b) that transport analysis — and more specifically analysis using discrete choice models — only considered the rational side of things, ignoring the emotive. With his post he wanted to canvass the views of transport academics on these matters, and asked three questions:

  1. Is (b) above true and discrete choice modelling deficient in the way it approaches matters such as ‘symbolism of a brand’ or ‘aversion to a mode’?
  2. If it isn’t, how does discrete choice modelling account for such things?
  3. Has any work actually quantified the % split between the ‘rational’ and the ’emotive’ when choosing to acquire and/or use a car.  Could this percentage vary by culture?

These are interesting questions and I couldn’t resist responding. This is (and edited version of) what I wrote:

I am afraid that the experts you have spoken to are not aware of recent developments in discrete choice modelling in transport studies. There is a growing number of empirical studies using discrete choice models to account for what you term ’emotive’ factors (more on this below). These studies tend to adopt one of the following approaches:

  1. Include measures of people’s attitudes, beliefs and values directly into the utility function — a good example of this line of work is provided by the work of Pat Mokhtarian at UC Davis. For an example of a study of vehicle choice, see her co-authored paper ‘What type of vehicle do people drive?‘ published in 2004 in Transportation Research A.
  2. Use a latent class model whereby people are endogenously classified into groups with similar preferences/attitudes as part of the choice model. I don’t have an example of this approach in the context of vehicle type choice at hand, but this approach is increasingly used (see e.g. Walker and Li’s 2007 paper ‘Latent lifestyle preferences and household location decisions‘ in Journal of Geographical Systems) and is directly applicable to decisions about what sort of vehicle people drive.

However, there is also a problem with the way the three questions are framed. There is a long history of dualistically opposing the ‘rational’ and the ’emotional’ in mainstream western thought, but evidence from a wide variety of sources suggests that this opposition is in itself very problematic: it is not possible to separate the two. In the neurosciences, for instance, it is now increasingly accepted that emotions are indispensable to good, or at least effective, decision-making — the work of Antonio Damasio is a key source here. In fact, one could argue that the opposition of the rational and the emotional is a somewhat curious particularity of the vagaries of mainstream western philosophy, and certainly not shared by all the mainstream philosophers of the past centuries. David Hume and some of the utilitarians, for instance, already acknowledged that the rational and the emotional were entangled in complex ways in (good) decision-making. These arguments imply that your third question is very problematic from a philosophical point of view — the question cannot be addressed in a meaningful way if one also wants to incorporate non-Western countries/cultures.

At the same time, there is much to say in favour of the criticisms articulated by the experts from marketing and psychology, but the key here is to distinguish between the ‘rational’ and the ‘instrumental’. In mainstream discrete choice modelling of travel behaviour, decisions regarding vehicle ownership, and so on, there has long been a tendency to privilege the instrumental aspects of behaviour — e.g. how can I get to X the quickest, at the lowest monetary costs and with the highest level of comfort? This one-sided focus on the instrumental has a long and complex genealogy and derives in part from theoretical considerations but also reflects data availability issues and the difficulty of constructing reliable measurements of the more-than-instrumental factors that mediate people’s decision-making.

The ‘expressive’ dimensions of behaviour and decisions about vehicle ownership have long been side-lined in transport modelling, and until fairly recently there has been little attention for the links between transport and identity (and symbolism) and for the links between transport/movement, sensory experience, affects and feelings. The most powerful work on those expressive dimensions can nonetheless be found outside the body of research drawing on discrete choice models; two strands of work would be particularly useful to consider:

  1. Research informed by thinking from behavioural psychology — see e.g. the work of Linda Steg (among others her 2005 paper ‘Car use: lust and must‘ in Transportation Research Part A)
  2. Research belonging to what John Urry and Mimi Sheller have called the ‘new mobilities paradigm’ — the best place to start here would be the work of Peter Merriman (his 2009 paper ‘Automobility and the geographies of the car‘ in Geography Compass provides an excellent introduction to this line of thinking)

Considering the more-than-instrumental is important in choice modelling; models that only consider the instrumental dimensions of individuals’ decision-making — e.g. travel time, travel cost, comfort, reliability — seem to systematically over-predict the extent to which people will change their behaviour or choices compared to what happens in the real world. The more-than-instrumental must be given much more attention if we want to move towards more sustainable transport systems.

Does Slime Mould Help Us to Rethink Land-based Transport Networks?

Today I read a fascinating piece on the Guardian‘s website about a study conducted by Andrew Adamatzky. He and his colleagues have conducted a series of great experiments on slime mould and the way in which this one-celled organism grows and builds a network or system linking different food resources. Its relative simplicity in evolutionary terms notwithstanding, this organism is known to behave ‘smartly’ and build its networks more or less rationally.

Adamatzky and colleagues poured agar on a globe and cut out the seas and oceans, so that the agar configuration resembled Earth’s land masses. They also placed oat flakes on the positions of the world’s megacities and other urban concentrations. They placed the slime mould on the flake representing Beijing and then observed how it built its network. Details are available here or here. They have previously used this methodology in a study of Australia’s major population concentrations and the road networks connecting them, available here.

A key finding of the study on the globe as a whole is that the slime mould’s network “approximates over 76% of the Silk Road routes and the Asian Highway routes”. The implication being that these historically emerged transport networks are quite rational — if not optimal — in terms of their structure. Indeed, Adamatzky writes that his research and findings “will help to design future transcontinental pathways”.

For a long time I have been fascinating by the idea of optimality in transport networks and the specific way in which optimal travel behaviour has been defined in travel behaviour studies (i.e. either in terms of minimising travel times or in terms of the optimisation of the ‘costs’ of travel and the ‘benefits’ to be reaped at the destination). So I very much welcome work such as Adamatzky’s because it sheds new light on the ‘trick’ by neo-classical economists to transpose the principle of least effort from physics to human behaviour. Perhaps there is an evolutionary edge to this principle, which the neo-classical economists grasped intuitively but were unable to prove? There must be literature on addressing this question and I would grateful for any references! Anyway, I mention neo-classical economics here because this body of thought has had such a profound influence on the history of transport and travel behaviour modelling.

At the same time, I am rather sceptical about Adamatzki’s claim that slime mould behaviour can really help us understand the configuration of surface transport networks. For there is a big difference between slime moulds’ quest for food and transport-land use interactions. At least in Adamatzki’s oat flaked world, the location and size of food sources are given (as an inevitable if understandable consequence of his experimental set-up). Though I clearly am no expert on slime mould, I would think that its spatial behaviour is essentially responsive: it reacts to a given state of affairs. And this differs fundamentally from ‘real world’ developments: as decades of transport geography research tell us, urban developments and transport infrastructure development co-evolve. There is no given and static world of cities; their size and growth is very much a consequence of how they are positioned and articulated in major transport networks (not only land-based transport but also maritime and aviation networks, and increasingly internet backbone networks).

So, to really help us understand the evolution of land-based transport networks, Adamatzki should re-design his experiment and add flakes at nodes in the networks built by the slime mould (and a set of rules would need to be deviced regarding how much the extra flakes would need to be added, although deriving those rules would be a less than straightforward task!). In this way feedback effects and positive reinforcement and ultimately the co-evolution of urban development and transport networks could be mimicked.

My hunch is that the slime mould’s networks would develop rather differently if that co-evolution were taken into account.