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 and 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.

New paper on well-being

Last week a paper I co-authored with Donggen Wang at Hong Kong Baptist University has appeared in the Annals of American Geographers. In this paper we argue that the Day Reconstruction Method devised by Daniel Kahneman and colleagues can be usefully linked to time-geography. One benefit of doing this is that what Mei-Po Kwan calls the Uncertain Geographical Context Problem (UGCoP) — spatiotemporal uncertainty in the actual areas or places that exert influence on the behaviour and experiences of individuals — that has characterised past studies of the geographical context on individuals’ subjectively experienced well-being. Another benefit is that the effect of spending time together with others (family members or friends) on one’s subjectively experienced well-being can be measured and examined more precisely.

Using data from Hong Kong we found that the influence of the actual location where people spend time for daily activities other than paid work is very limited (at least as far as we were able to measure characteristics of that location); the effect of where individuals live on their overall life satisfaction was much stronger. Further work is therefore required to better measure and examine how the places where people spend time affects their subjective experience of well-being.

We did find that doing things together with others makes them happier than doing the same things alone, and it also appears that the relationship between the duration of a daily activity and people’s subjectively experienced well-being depends on with how they have undertaken that activity. One implication of this finding is that the relationships between social capital and subjectively experienced well-being cannot be examined or understood properly without due attention for individuals’ everyday life — i.e. their actual time-use and space-time path.

A limited number of free copies of the article is now available from here.

International time-geography days

A while has past since the last post, and a lot has happened. This includes not least the annual conference of the Association of American Geographers in Tampa (FL) in April during which Mei-Po Kwan and myself convened seven inspiring sessions on the ‘Geographies of Mobility’, in which geographers from many different hues — i.e. working from a wide range of theoretical and methodological perspectives and focusing on a vast array of topics — come together and learned about each other’s work.

More recently, 14-16 May, I attended the International Time-Geography Days at Linköping University, organised by Torsten Hägerstrand’s former student, professor Kajsa Ellegård, and her former student, Elin Wihlborg. They did a wonderful job in organising an excellent conference, and took us to the rural area around Åsby parish where Hägerstrand conducted the fieldwork for his PhD thesis (together with his wife). Nowadays Åsby is a peaceful — if ageing and still shrinking — community. It is quite hard to imagine now that this is the setting in which Hägerstrand began to develop his ideas about budget-space, Rum, and the competition between projects for space and time as scarce resources, all of which are at the heart of time-geography. Life in the Åsby area must have been much harsher some 50-60 years ago. Obviously, the fact that we as casual visitors — tourists almost — were visiting the area on a very sunny day must have formatted my perceptions as well.

Tucked away in boxes and on shelves in a back office somewhere in Linköping University can Hägerstrand’s books and notes be found. It was here that I made the following picture:








In a way the quote from Goethe typed up by Hägerstrand sums up time-geography quite nicely: “Everything that comes into being searches for space and will last, thereby crowding out something else from its place and shortening its duration“. Competition for space and time — the essence of time-geography as envisaged by Hägerstrand in the 1970s — articulated at its best.

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.

Urban and suburban geographies of ageing

Call for papers for two papers sessions at the RGS/IBG Conference, sponsored by the Urban Geography Research Group and the Geography of Health Research Group.


  • Bettina van Hoven (Cultural Geography Department; Faculty of Spatial Sciences; University of Groningen; The Netherlands)
  • Debbie Lager (Cultural Geography Department; Faculty of Spatial Sciences; University of Groningen; The Netherlands)
  • Chiara Negrini (School of Geography, Geology and the Environment; Faculty of Science, Engineering and Computing; Kingston University; Kingston upon Thames)
  • Tim Schwanen (School of Geography and the Environment, University of Oxford)

We seek to organise two sessions to explore the relationships of older people and ageing with place, with a particular focus on urban and suburban environments. Up till now, research in the field of ageing and place has been dominated by social and environmental gerontologists. Recently, Schwanen et al. (2012) advocated a more ‘sustained engagement’ with ageing from geographers in order to draw attention to the different spatial configurations of old age and the socio-spatial inequalities in later life. These socio-spatial inequalities stem from a complex interplay of the social and material environment and the biological and psychological aspects of the ageing body (see e.g. Ziegler, 2012). Research on ageing in urban environments has highlighted the exclusionary processes to which older adults can be subjected, such as the obstacles for everyday mobility and the challenges of everyday life in deprived urban neighbourhoods (see e.g. Smith, 2009; Buffel, 2013). However, it has also been acknowledged that older people can make active and important contributions to their community and can make their (urban) neighbourhood and home into a place that evokes positive experiences and attachments.

Arguably, however, the vast majority of older people in the near future will age-in-place in suburban areas rather than live in densely populated urban centres. Whilst historically not developed for older people, suburban areas are now being (re)designed and (re)organised to meet the material and social needs of their older residents (e.g., through the implementation of integrated service areas – ISAs). Given the policy relevance of this trend, further research is needed with regard to how ageing-in-place in suburban neighbourhoods is experienced and what the socio-spatial implications of these environments are for its older population.

We encourage papers that investigate the multiple relationships between ageing and the urban and suburban environment, with particular attention to:

  • Intersections of age with gender, ethnicity, class, sexual orientation and other forms of social identification and exclusionary processes related to these intersections;
  • Theoretical advancement within the field of ‘geographies of ageing’;
  • Participatory methodologies and ethical considerations relating to this type of research;
  • Contributions of older people to their local community;
  • Meanings, experiences and emotions related to ageing-in-place; and
  • Planning processes that make cities and suburbs more age-friendly and the role of older people herein.

Abstracts (max. 200 words) should be submitted by 10th February 2014 to Chiara Negrini ( and Debbie Lager (

Happy New Year

Happy 2014! It has been a while since my last post, which is largely because I have been in Hong Kong for most of December to work on some joint research with Prof Donggen Wang on well-being and to attend two conferences. I gave a plenary during the 18th Conference of the Hong Kong Society for Transportation Studies on the insights that can be derived from Whitehead’s philosophy for the analysis of processes of change in transport (see picture).


And on the day prior to the main conference I gave a keynote on how I believe activity analysis in transport studies should be reconfigured so that we can better understand how socio-technical innovations in urban transport (e.g. car sharing schemes or electric vehicles) change, develop and diffuse over time in particular places. I will probably discuss this work in a later post.

Apart from working and attending conferences, I have also had the opportunity to experience the fantastic city that is Hong Kong — a paradise for urban geographers interested in processes of urban expansion, growing sociospatial inequality and low carbon urban mobility. I visited Hong Kong in 1998, just after the hand-over, but the city has changed almost unrecognisably since: it has grown in terms of population size, ‘neoliberal’ urban (re)development projects are now much more common, social inequalities have increased markedly, and the city has become much more Chinese than it was in my memory. It has not, however, lost any of its positive energy. If anything, its vitality has only increased and easily surpasses that of Europe’s major cities. It is now truly a global city where East and West mingle in all kinds of innovative and inspiring ways!

Living in enclave cities: Towards mobility-based perspectives on urban segregation

Call for papers for a seminar in Utrecht, the Netherlands, 21-22 March 2014

Organisers: Ronald van Kempen (Utrecht University), Tim Schwanen (University of Oxford), Bart Wissink (City University Hong Kong)

We are inviting abstracts for contributions to the upcoming two-day expert workshop on “Living in Enclave Cities: Towards Mobility-Based Perspectives on Urban Segregation”. An exciting list of confirmed speakers can be found below, and we are looking to accept abstracts from some 10 additional speakers. Upon selection, participants are expected to submit an unpublished original full paper by 3 March 2014. There is no registration fee for the workshop and lunch and drinks will be provided but we are unable to reimburse expenses for travel and subsistence. Please send abstracts of 200-250 words to no later than 3 November.


Urban spatial segregation has long been a core concern in urban studies research. Recently, it has received new impetus through the emergence of a new form of enclave urbanism with cities restructuring into patchworks of separate enclaves that are each of home to a selected group or activity. While premium enclaves are well connected by new privatised infrastructures, enclaves for the underprivileged are increasingly cut-off. ‘Enclave urbanism’ thus radicalises segregation. Critics stress that ‘enclave urbanism’ prevents social interaction. Well-off people can go about their daily life in premium enclaves without confrontations with others. While we agree with critical questions regarding the social effects of ‘enclave urbanism’, we also observe a strong bias in this argument: research one-sidedly focuses on the effects of residential segregation. It is assumed that segregated living will automatically have social effects. However, with increased ‘mobilities’, people easily can and will meet in other places – on-line and off-line – than residential neighbourhoods; and ‘outsiders’ might also visit urban amenities in residential enclaves.

Objective of the seminar

The usefulness of place-based perspectives on residential segregation seems to have diminished considerably in today’s world of mobilities, where living in the same neighbourhood does not necessarily imply face-to-face contact and living in different neighbourhoods does not prevent such contact. This seminar aims to develop a mobility-based perspective on segregation, bringing together world-class researchers on segregation, mobilities, transport, and infrastructure.

Nature of the event

This objective will be realised through a 2-day intensive seminar hosted by Utrecht University on 21-22 March 2014. The seminar will cover theoretical discussions on ‘enclave urbanism’, segregation and mobility, and empirical studies on these issues in global city-regions.

Confirmed participants

The confirmed participants include five keynote speakers: Susan K. Brown (UCI), Mei-Po Kwan (UIUC/Utrecht University), Karen Lucas (University of Leeds), John Urry (Lancaster University), and Donggen Wang (Hong Kong Baptist University).

Additionally, the following group of experts have confirmed their participation: Rowland Atkinson (University of York), Willem Boterman (University of Amsterdam), Martin Dijst (Utrecht University), John Dixon (Open University),  Maarten van Ham (TU Delft), Markus Hesse (University Luxembourg), Christa Hubers (TU Delft), Lucia Lo (University of York), Thomas Maloutas (Harokopio University), Sako Musterd (University of Amsterdam), Antonio Paez (McMaster University), Deborah Phillips (University of Oxford), Gill Valentine (University of Sheffield), Helen Wilson (University of Manchester), David Wong (George Mason University), and Ngai-ming Yip (City University Hong Kong).

The timeliness of A N Whitehead: uncertainty

I have just finalized a book chapter in which I have argued that the philosophy of Alfred North Whitehead can inform contemporary transport research in a number of ways. That may come as a surprise, given that this mathematician-philosopher published his major philosophical works in the 1920s and 30s — a time when scholars were trying to come to terms with the consequences of Darwin’s work, Einstein’s theories and Quantum theory for how life and the world were to be re-imagined.

But it is not, for a variety of reasons. One of these is that Whitehead’s offers an interesting perspective on questions of indeterminacy and uncertainty with regard to how transport systems evolve over time. In a way his philosophy anticipated contemporary concerns over ‘deep uncertainties’ — situations in which analysts cannot enumerate which futures are more likely to unfold because they do not fully understand, or cannot agree on, the causal mechanisms and functional relationships between the phenomena or processes being studied. It is no secret that transport planning is ill-equipped to deal with such uncertainties and often ignores these — even most forms of scenario analysis used in transport research fail to come to terms with fundamental uncertainty about the nature of causal mechanisms. Relatively recently, however, Walker and colleagues have begun to tailor and apply their adaptive policy making approach to transport planning.

This is not the place to fully review this approach. Suffice it to say that Walker c.s. build a range of steps and practices in the policy development process in which policy-makers have to appreciate vulnerabilities — factors that may complicate or compromise a policy’s success. Some of these can be anticipated (certain vulnerabilities) and other cannot be anticipated (uncertain vulnerabilities). A central idea of the approach is that policy-makers hedge themselves to the effects of those uncertainties and monitor whether some form of adaptation of the original policy is required.

Walker et al.’s approach has many strengths, and it would be great to see it applied in transport planning practice. But perhaps its central premises are also are also a weakness. For the approach assumes first of all that uncertainty over the nature of causal mechanisms will be reduced over time as event unfold and second that, as things will become clearer and more information becomes available, policy-makers can respond to those and adapt policy action if and when needed. But what if uncertainty is more profound? What if the nature of causality is such that it only can be understood with hindsight, when the tables have turned? In that case adaptation can only be reactive rather than proactive.

It might be argued that situations like these resemble Taleb’s black swans but they may occur more often and with (much) more limited ramifications. It seems to me that Whitehead’s philosophy offers one way to think about these situations. Now, his philosophy is notoriously difficult and technical, and I won’t be able to do any justice to it here. Readers would need to turn to Process or Reality or alternative the Adventures of Ideas.

Let me therefore say this: According to Whitehead’s philosophy the world consists completely of events, and these can be broken down in ever smaller events until one arrives at the smallest possible ‘unit’ of event (which he called ‘actual occasion’). Crucially, how these actual occasions unfold can never be known fully in advance. There is always an immanent possibility that something new or unexpected will happen, however dim this possibility may be. Indeterminacy can never be ruled out completely. Uncertainty is not epistemic — a consequence of lack of knowledge — but ontological and hence an irreducible part of the world itself. The question then is under what circumstances it is more or less problematic to make (reasonable) assumptions about the nature of causal mechanisms.

The full consequences of a Whiteheadian perspective on uncertainty for transport research and planning obviously need much more thought, and I would expect that they will make many researchers profoundly uneasy. As an example consider the following: if one can never be fully sure about the character of causal mechanisms of (future) events, then all research into such matters is by definition speculative. There can be no — and arguably should not be any — separation between the practices of the researchers and research outcomes. Whilst ideas such as these may be rather common to many scholars with a background in science studies, I suspect they will be difficult to accept for quite a few transport researchers and planners.

Even so, I believe that transport planning and research can benefit immensely from sustained engagement with Whiteheadian perspectives on uncertainty and causality.

Popular papers on transport

Elsevier — the academic publisher which publishes the most and the most highly ranked journals in transport research — has published a list of transport papers from its journals that have been downloaded the most over the first half of 2013. The list is available here and all papers on it can be downloaded for free until 31st October 2013.

One obviously has to be careful with attributing significance to lists of download frequency, for they don’t tell much about the reasons for the downloads — papers may, for instance, have been used for university courses with many students, or one or two individuals may have downloaded a paper repeatedly whilst working on a particular piece of research. Still, the list contains a number of papers one would expect to be there (e.g. Chapman’s paper on #2 and Banister’s on #7), and this tells us something about popularity and influence.

I wish to highlight two aspects of the list.

First, and to my delight, the Journal of Transport Geography has two papers in the top 5 — the aforementioned review on climate change and transport by Chapman and the position paper by Hesse and Rodrigue on the transport geography of logistics and freight distribution.

Second, there are some differences between Elsevier’s transport journals with the highest impact factor and the ones that feature most prominently on the list of most downloaded articles. For there are comparatively few papers from Transportation Research Part B and Part A. The journal that dominates the list of most frequently downloaded papers and particularly its higher echelons is Transport Policy, the impact factor of which is with 1.51 significantly lower than for Transportation Research Part B (2.94) or Part A (2.75). At the same time, the list confirms the position of Transportation Research Part E (IF=2.27) as a leading journal in the field.

Nonetheless, as a whole the list goes to show that the use of a single metric to rank journals is quite problematic. Insofar as journals are to be ranked — the usefulness of which I, like many others, have strong doubts about — multiple indicators should be used. No single indicator is perfect but if a broad range of different indicators is employed, it is possible to create a richer and more realistic picture of the position of any given journal in the wider field than with the current narrow focus on journal impact factors.

Seminar on Social Theory, Transport and Energy Modelling

I will be speaking at one of the seminars organised by Rachel Aldred (University of Westminster) in the context of the ESRC-funded seminar series Modelling on the Move: Towards Transport System Transitions? on 13th September in London.

This particular event focuses on the relevance of social theory for transport and energy modelling, and my talk will offer reflections on the way transport researchers have conceptualised, understood and ‘done’ process and change over the past decades. It will problematise conventional ways in which change has been examined and argue that insights from ‘process philosophies’ can usefully inform standard practice in transport research. Process philosophies are a heterogeneous collection of philosophical thinking, including amongst others the work of authors as diverse as Henri Bergson, William James, Gilles Deleuze, Isabelle Stengers, Bruno Latour and also Alfred North Whithead. IN the presentation and accompanying paper I will be drawing on the latter and show how his philosophical ideas and metaphysics can be used to think about change in a transport research context.

More information on the seminar, including an abstract of my talk, is available here, and registration for the seminar can be done here.