Aspects of spatial proximity and sustainable travel behaviour in Flanders: A quantitative approach

Aspects of spatial proximity and sustainable travel behaviour in Flanders: A quantitative approach 1

Cover: The picture on the cover ( Rocky Zutterman) is a remake of the painting Il ciclista attraversa la città, by the futurist Fortunato Depero (1945). The Futurism movement revered speed, technology and industry, and was thus not particularly advocating sustainable mobility, despite the iconic use of a bicycle in this work of art. Copyright Kobe Boussauw, Department of Geography, Faculty of Sciences, Ghent University, 2011. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without permission in writing from the copyright holder(s). ISBN: 978-94-906-9553-8 Legal deposit: D/2011/12.134/6 NUR: 755/901/904/976 The research reported in this dissertation was conducted at the Social and Economic Geography research unit, Department of Geography, Faculty of Sciences, Ghent University, and funded by the Policy Research Centre on Regional Planning and Housing - Flanders (Steunpunt Ruimte en Wonen 2007-2011). 2

Aspects of spatial proximity and sustainable travel behaviour in Flanders: A quantitative approach Aspecten van ruimtelijke nabijheid en duurzaam verplaatsingsgedrag in Vlaanderen: Een kwantitatieve benadering Proefschrift Proefschrift aangeboden tot het behalen van de graad van doctor in de wetenschappen: geografie vrijdag 4 maart 2011 door ir. Kobe Boussauw 3

Promotor: prof. dr. Frank Witlox, Universiteit Gent Samenstelling examencommissie: prof. dr. Georges Allaert, Universiteit Gent prof. dr. David Banister, University of Oxford prof. dr. Peter Cabus, Katholieke Universiteit Leuven prof. dr. Ben Derudder (voorzitter), Universiteit Gent prof. dr. Martin Dijst, Universiteit Utrecht prof. ir. Dirk Lauwers, Universiteit Gent prof. dr. ir. Jacques Teller, Université de Liège dr. Veronique Van Acker, Universiteit Gent 4

Contents Preface 9 Chapter 1: Introduction 15 1.1 Summary 15 1.2 Sustainable mobility, climate change and peak oil 16 1.3 The time-distance-space relationship 25 1.4 The rebirth of distance 33 1.5 Flanders and Brussels: policy context 45 1.6 Research questions, conceptual framework and implementation 47 1.7 Overview of the research 51 References 55 Chapter 2: Introducing a commute-energy performance index 63 Abstract 63 2.1 Introduction 64 2.2 Energy use and urban spatial structure 64 2.3 Limitations of studying the home-to-work commute 66 2.4 Commute-energy performance (CEP) index 67 2.5 Geographical setting and data analysis 68 2.6 Results 72 2.7 Relation to spatial-morphological characteristics 81 2.8 Conclusions 84 References 85 Chapter 3: Minimum commuting distance as a spatial characteristic in a non-monocentric urban system 89 Abstract 89 3.1 Introduction 90 3.2 Spatial variations in excess travel 92 3.3 Possible policy implications 94 3.4 Methodology 95 3.5 Case study area: Flanders and Brussels (Belgium) 102 3.6 Application and results of the case study 106 3.7 Possible biases 113 3.8 Conclusions 113 References 115 5

Contents Chapter 4: Measuring spatial separation processes through the minimum commute 119 Abstract 119 4.1 Introduction 120 4.2 Defining spatial separation processes 122 4.3 Measuring spatial separation by excess commuting characteristics 124 4.4 Spatial development and commuting in Flanders and Brussels 128 4.5 Data 131 4.6 Method 132 4.7 Results 134 4.8 Conclusions 143 References 145 Chapter 5: Excess travel in non-professional trips: Why looking for it miles away? 149 Abstract 149 5.1 Introduction 150 5.2 Excess commuting and excess travel 152 5.3 Methodology 156 5.4 Determination of spatial classes 157 5.5 Developing a proximity map 159 5.6 Reported trip lengths 166 5.7 Excess travel 171 5.8 Possible biases in the results 174 5.9 Conclusions 176 References 178 Data sources 181 Chapter 6: Relationship between spatial proximity and travel-to-work distance: The effect of the compact city 183 Abstract 183 6.1 Introduction 184 6.2 The relevant literature 187 6.3 Methods 190 6.4 Results 200 6.5 Discussion 212 6.6 Conclusions and pathways for further research 214 References 215 6

Contents Chapter 7: Linking expected mobility production to sustainable residential location planning 221 Abstract 221 7.1 Introduction 222 7.2 Study area 225 7.3 Methodology and data 225 7.4 Analysis 230 7.5 Forecasting model for Flanders 233 7.6 Discussion 235 7.7 Conclusion and directions for further research 237 References 238 Chapter 8: Conclusions and policy recommendations 243 8.1 General conclusions 243 8.2 Options for spatial planning policy 251 8.3 Some directions for further research 257 References 258 Addendum: The spatial component of air travel behaviour: An exploration 261 A.1 The aeroplane: the forgotten transport mode 261 A.2 Urban versus rural lifestyle 264 A.3 Rebound effect and policy implications 265 References 266 Samenvatting 269 S.1 Overzicht 269 S.2 Onderzoeksopzet 270 S.3 Bevindingen 272 S.4 Aanbevelingen voor het ruimtelijk beleid 277 S.5 Verder onderzoek 279 Referenties 279 Curriculum vitae 281 7

Contents 8

Preface (English version below) Na ruim drie jaar werken aan dit proefschrift is het tijd om er de laatste hand aan te leggen. Hoewel het niet de bedoeling lijkt dat een woord vooraf áchteraf geschreven wordt, is deze omgekeerde volgorde noodzakelijk om een terugblik te kunnen werpen. Want wat bracht mij er eigenlijk toe om me te verdiepen in mobiliteit en ruimtelijke ordening? Volgens de overlevering was mijn eerste woordje mama en mijn tweede lamborghini, verwijzend naar een paars matchbox-autootje dat deel uitmaakte van mijn eerste verjaardagsuitzet. Een volgende stap in deze evolutie was dat ik rond mijn dertiende op zaterdag op de fiets sprong om aan mijn nieuwe hobby te werken, die bestond uit het verzamelen van prospectussen voor auto s. Hoewel dat doorgaans vlot ging bij garages die gespecialiseerd waren in Renault of Volkswagen, werden er al eens wenkbrauwen gefronst toen ik op zekere dag de moed had om de toonzaal van Rolls-Royce te betreden. Deze vroege interesse voor auto s heeft echter weinig opgeleverd: tot op de dag van vandaag heb ik mij nooit een wagen aangeschaft. Met het ouder worden groeide mijn belangstelling voor het leefmilieu en begon mijn interesse zich te verschuiven naar fietstechniek. Handig, want die nieuwe sportfiets was niet alleen een perfect vervoermiddel voor de stad, maar ik kon er ook de weekends en de vakanties mee vullen. Tijdens mijn opleiding in architectuur en planning maakte ik een ontwerp voor een fietsvriendelijker heraanleg van het kruispunt De Sterre in Gent. Dat werd uiteraard nooit uitgevoerd, en ironisch genoeg is dit de plek waar ik de laatste drie jaar weer elke dag tweemaal op lichtjes suïcidale wijze langs fiets. Een volgende stap was mijn eerste job, als consultant verkeerskunde, waarbij ik ingeschakeld werd in de opmaak van mobiliteitsplannen, en waarin ik de aanleiding vond om mijn studie in de ruimtelijke planning aan te vullen met nog een opleiding verkeerskunde. Jaren later, in het UN-Habitat-team in Kosovo, zou deze achtergrond weer zeer goed van pas komen bij het ontwikkelen van ruimtelijke en mobiliteitsplannen in een heel andere context. En uiteindelijk bleken mobiliteit en planning ook een domein te vormen waarin nog heel wat theoretische onderzoeksmogelijkheden braak 9

Preface lagen. Mijn beslissing om daarin te stappen heb ik me niet beklaagd, getuige daarvan dit proefschrift. Dan rest mij nog de eer en het genoegen om een reeks mensen te bedanken, zonder wie dit werk er vandaag niet zou liggen. In de eerste plaats komt natuurlijk professor Frank Witlox, mijn promotor, die mij eind 2007 een goede reden gaf om Kosovo weer voor België in te ruilen. Hij zorgde voor het onderzoekskader en gaf mij de tijd en ruimte om cursussen te volgen en aan congressen deel te nemen. Van hem kreeg ik het vandaag in academische kringen zo gewaardeerde peer review- en publicatievirus te pakken. En met resultaat: de zes basishoofdstukken van het voorliggende proefschrift hebben een peer review -proces doorstaan en zijn (of worden) gepubliceerd in een reeks hoogstaande wetenschappelijke tijdschriften. Een snel optelsommetje leert dat er in de loop van het schrijven van deze verhandeling maar liefst achtentwintig internationale reviewers hebben bijgedragen tot de kwaliteit van dit werk. Hoewel deze experts doorgaans anoniem optraden, heb ik hun inspanning zeer gewaardeerd. Maar dichterbij huis, op de werkvloer van de sociaal-economische geografie (SEG), zijn er wel meer mensen die een plaats verdienen in een dankwoord. Ik denk vooral aan Tijs Neutens, Veronique Van Acker, Thomas Vanoutrive, Enid Zwerts en Nathalie Van Nuffel die op tijd en stond methodologische ondersteuning boden, in het bijzonder in het eerste jaar, toen de wondere wereld van statistiek, dataverwerking en GIS zich nog aan mij aan het openbaren was. Daarnaast heb ik ook de inbreng van andere SEG-onderzoekers van het eerste uur enorm gewaardeerd: David Bassens (die nog steeds op zoek is naar een manier om de kloof tussen het wereldstedenonderzoek en het mobiliteitsonderzoek te dichten), Heidi Hanssens (die altijd klaar stond om de sociale omkadering te verzorgen), Sven Vlassenroot (die de koffiepauzes steevast met nuttige weetjes over de academische wereld kwam opvrolijken), Lomme Devriendt (die de SEG vorm gaf) en professor Ben Derudder (die zijn nuttige tips van de zijlijn gaf). Daarmee wil ik de rest van de Vakgroep Geografie uiteraard niet vergeten; één speciale vermelding nog voor Helga Vermeulen, zonder wiens organisatorische en administratieve nauwgezetheid ik wellicht niet eens aan de universiteit was kunnen beginnen. Maar ook buiten de Vakgroep Geografie heb ik heel wat ondersteuning gekregen. De tientallen mensen (onderzoekers, promotoren en coördinatoren binnen de verschillende universiteiten, en begeleiders van de Afdeling Ruimtelijke Planning) achter het Steunpunt Ruimte en Wonen (dat mijn onderzoek 10

Preface financierde) verdienen hier dan ook een extra vermelding, net zoals Jos Zuallaert en Dirk Lauwers die mij de mogelijkheid boden om van tijd tot tijd nog wat in de planningspraktijk te gaan werken in Kosovo. Tot slot nog een bedankje voor zij die mijn activiteiten van buiten de werkvloer volgden, maar er niet voor terugschrokken om over mijn onderzoek in discussie te gaan: eerst en vooral mijn ouders, Johan en Kristien, maar ook mijn drie zussen (Anna, Marieke en Mathilde), oma Simonne, het wekelijkse badmintongezelschap (Filip, Wouter, Bram en Piet) waar de evolutie van de olieprijs een steeds weer opduikend thema was, Rocky (die de lichtjes controversiële kaft van dit boek leverde), Hermes (die bijna wekelijks naar de stand van zaken informeerde) en dan nog een hele reeks van vrienden, familie, reisgenoten, huisgenoten en facebook-friends die in de loop van de laatste jaren hun interesse lieten blijken. Merci, allemaal! After more than three years working on this thesis, the time has come to add the finishing touch. Although the word preface does not sound as if it is intended to be written afterwards, this reverse order is necessary to allow looking back. Because why did I bury myself in the study of mobility and spatial planning? According to tradition, my first word was mama and my second lamborghini, referring to a purple matchbox-car that was one of my first-birthday presents. As a next step in this evolution, when I was thirteen, on Saturdays I jumped on my bike to work on my new hobby, which consisted of collecting commercial prospectuses for cars. Although this went generally smoothly in garages that specialized in Renault or Volkswagen, some eyebrows raised when on a certain day I had the courage to enter the showroom of Rolls-Royce. However, this early interest in vehicles did not yield that much: up to now, I never bought a car. With age, my interest in the environment increased and I started concentrating on bicycle technology. That was quite convenient, because my new touring bike was not only a perfect transport means in the city, but I could also use it to fill my weekends and holidays. During my training in architecture and planning, I devised a bicyclefriendly redesign of the intersection De Sterre in Ghent. Of course, my design was never implemented, and ironically, during the last three years, 11

Preface this is the place where I cycled through every day twice in a slightly suicidal manner. A further step was my first job, as a traffic and mobility consultant, where I was called in to develop municipal mobility plans. In this job, I also found a good reason to supplement my studies in spatial planning with an advanced course on traffic and mobility. Some years later, in the UN-Habitat team in Kosovo, this background proved again very useful in developing urban plans and mobility plans in a quite different context. Ultimately, mobility and planning turned out to be a domain where many theoretical research opportunities were still present. And I can say that I have no regret on my decision to get into this, as is demonstrated today by this dissertation. Of course, I would like to use this opportunity to thank a number of people, without whom this work would not be accomplished today. In the first place there is of course Prof. Frank Witlox, my supervisor, who gave me at the end of 2007 a good reason to exchange Kosovo for Belgium again. Frank provided the research framework and gave me the time and space to follow courses and participate in conferences. He transferred the peer review and publication virus to me, which is highly valued in academic circles. This was not without success: all of the six basic chapters of the present dissertation have gone through a peer review process and are (or will be) published in a series of high ranking academic journals. A quick summation shows that twenty-eight international reviewers have contributed to the quality of this work. Although these experts usually performed anonymously, I greatly appreciate their efforts. Closer to home, at the Social and Economic Geography (SEG) research cluster, there are more people who deserve a place in this expression of gratitude. Tijs Neutens, Veronique Van Acker, Thomas Vanoutrive, Enid Zwerts and Nathalie Van Nuffel have all offered methodological support to me, especially in the first year, when the wonderful world of statistics, data processing and GIS was still in the process of revealing itself to me. In addition, I also have greatly appreciated the input from other SEG-researchers who were there in the very early stage of my study: David Bassens (still looking for a way to bridge the gap between world city research and mobility research), Heidi Hanssens (who was always ready to care about the social environment), Sven Vlassenroot (who was invariably cheering up coffee breaks with interesting academic rumours), Lomme Devriendt (who was responsible 12

Preface for the SEG house style) and Prof. Ben Derudder (who contributed with useful tips from the sideline). This is of course not to forget the rest of the Geography Department, while I would like to add a special note to Helga Vermeulen, without whose organizational and administrative accuracy I may not even have started working at Ghent University. But even outside the Geography Department, I got a lot of support. The dozens of people (researchers, supervisors and coordinators within the different universities, and the coaches of the Ministry s Spatial Planning Department) working for the Policy Research Centre on Regional Planning and Housing (which funded my research) deserve a special mention here too, just as Jos Zuallaert and Dirk Lauwers who offered me the possibility to do still some practical planning work in Kosovo. Finally, a word of thanks to all those who observed my professional activities from outside, but were not afraid of getting involved in some debate on my research topic. First and foremost I should mention my parents, Johan and Kristien, but also my three sisters (Anna, Marieke and Mathilde), my grandmother Simonne, the weekly badminton company (Filip, Wouter, Bram and Piet) (where the oil price trend was an ever resurfacing theme), Rocky (who made the slightly controversial cover of this book), Hermes (who informed almost weekly on the state of affairs), and of course the whole series of friends, family, travel companions, housemates and facebook-friends who demonstrated their interest during the last couple of years. Merci, everyone! 13

Preface 14

Chapter 1: Introduction 1.1 Summary An often-heard statement says that the interaction between mobility policy and spatial planning practice needs more coordination. Any concerned politician or citizen feels that the perceived increase in car traffic, and the growth of problems that are associated with car use, have something to do with unorganized urban expansion, sprawling new housing and industrial allotments, and ribbon development. Nevertheless, it is less clear how this relationship exactly looks like, leaving alone the question how planning should be used as a tool to improve accessibility and steer mobility to a more sustainable course. This dissertation wants to gain insight in the reciprocal relationship between mobility and spatial development, taking into account the societal context of climate targets and imminent peak oil. This will be done through the development of a number of quantitative research methods, which are embedded in a literature review and will be applied to the case study of Flanders (Belgium). 1 This broadly defined research objective is narrowed to the mobility of people, and will focus on exploring the sustainability of spatial structure with respect to travel behaviour, with particular attention to the daily distances travelled. Sustainability is defined in terms of resilience, not only for growing mobility but also for a possible declining future mobility. A generally declining mobility is a scenario that may develop due to rising energy costs (e.g. peak oil scenario) or stringent climate policies, while a selective shrinkage of mobility (only affecting parts of the population) may occur through increased saturation of the traffic system. Moreover, spatial structure plays a role in the potential steering of travel behaviour in a more sustainable direction. 1 The reason for this research is found in the mission statement of the funding Policy Research Centre on Regional Planning and Housing - Flanders (2007-2011), a policy-oriented research consortium that is administered by the Department of Planning, Housing and Heritage of the Flemish government. 15

Chapter 1 We refer to the research line on the connection between spatial structure and travel behaviour, which has developed mainly in the Englishspeaking, German, Dutch and Scandinavian world, and whose preliminary conclusions can be formulated as follows: A sustainable travel pattern can only be realized within an appropriate spatial framework, but other measures (financial and regulating) are needed to effectively change travel behaviour. In other words, planning is necessary but not sufficient (after Zhang, 2002, p. 3). The spatial quality that facilitates a travel pattern based on short distances is called spatial proximity, even though this concept has not been clearly defined in the exploratory phase of this research. This introductory chapter is structured as follows. Section 2 provides an overview of climate change and peak oil, two global phenomena that are directly related to the external effects of mobility. Section 3 deals with some captivating aspects of time and space perception and increased prosperity that underpin the growth of mobility. Section 4 gives an overview of the possible role of spatial structure in a future-oriented approach to mobility. Section 5 presents a snapshot of the spatial policy context in Flanders and Brussels. Section 6 focuses on the research questions, establishes a conceptual framework and states how the research will be conducted. Section 7 gives an outline of Chapters 2 to 7, each of which studies a separate aspect of the problem and can therefore be read as an individual article. 1.2 Sustainable mobility, climate change and peak oil The objective of coming to a less car-dependent and, by extension, a less oil-dependent transport system can be argued from different perspectives. Local environmental and safety problems caused by transport have already been in the spotlight for several decades. The principal issues in this debate are air pollution, noise, deterioration of the livability of residential areas, accidents and ecological and landscape fragmentation. This environmental approach is part of what is called sustainable mobility in the recent transport literature. Banister (2008) identifies four components that may contribute to the transition to a more sustainable transport system: (1) reducing the need to travel through substitution, (2) achieving a modal shift through transport policy measures, (3) 16

Introduction distance reduction through land-use policy measures, and (4) efficiency increase through technological innovation. Especially in the field of air pollution, accidents and livability, we can say that in the western world a lot of progress has been made by a combination of the mentioned policies and technological developments. We do not elaborate on this: for an overview we refer to Gilbert and Perl (2008, pp. 189-264). However, in terms of climate change (an environmental problem) and peak oil vulnerability (an economic problem), there seems to be much less progress. Below, we examine these two global phenomena, considering that these could constitute a major incentive to reduce the oil dependence of the transport system. 1.2.1 Climate change It seems that around 1995, in the scientific community, a consensus was reached on the acknowledgement of climate change as an important human-caused problem. With the Kyoto Protocol (1997), which was ratified by almost all concerned countries except the US, it became clear that these countries recognized anthropogenic climate change as a problem and, at least in a rhetorical sense, wanted to commit themselves to cut greenhouse gas emissions. In the Kyoto Protocol, Belgium, for instance, is committed to limit its emissions levels by 2012 to 92% of the 1990 level. Since 2001, we see that climate change both in the peerreviewed literature and outside it has become an established phenomenon (Weart, 2010). Climate change is caused by greenhouse gases, of which carbon dioxide (CO 2 ) is the most important. In 2006, transport was worldwide responsible for 23% of the energy-related greenhouse gas emissions. One fifth of the projected increase in emissions comes on account of transport, mainly in the form of increasing ownership and use of passenger cars in non-oecd countries and a general increase in international air travel and overseas cargo shipping (IEA, 2008). In 2005, in the European Union (EU) 80% of all greenhouse emissions was energy-related, including 24% (equalling 19% of total emissions) that was transport related. The international bunkers (fuel used by international aviation and shipping, both intra-european and intercontinental) are not yet included in these figures. In the period 1990-2005 greenhouse 17

Chapter 1 gas emissions in the EU decreased in all sectors, except in transport (+26%) and international bunkers (+64%) (EEA, 2008). In Flanders, greenhouse gas intensity in transport (this is the amount of emissions per person-kilometre, or per ton-kilometre for freight) decreased slightly in the period 1999-2005, but the absolute growth of traffic offset this efficiency gain well and ensured an absolute increase in emissions (by 1.50 megatons of CO 2 equivalent per year, an increase of 12% over the period 1990-2007) that was the greatest in the transport sector (again, international bunkers are not yet included). This sector was therefore largely responsible for not achieving the intermediate emission reduction targets of the Flanders Region for 2005, even though in 2007 the Kyoto target was still met. This last evolution was due to the manufacturing industry which recorded over the last period a reduction of 5.33 megatons of CO 2 equivalent per year (VMM, 2008, pp. 95-96). Regarding the transport sector, the Flanders Climate Policy Plan (LNE, 2006) focuses on achieving a modal shift, increasing overall efficiency, and improving the economy of the fleet. However, no measures that would curb the autonomous growth of traffic are proposed and international aviation and shipping are even completely out of focus. Although in Flanders the growth rate of personal car travel has almost reached zero in recent years (SVR, 2010), the complete traffic volume seems to be mainly associated with economic dynamics, rather than with climate policy. Moreover, both freight (SVR, 2010) and international air traffic with origins and destinations in and around Flanders was growing steadily up to 2008 (Brussels Airport, 2009). Transport is clearly bottom of the class when it comes to greenhouse gas emissions. Although efficiency improvement in vehicles is indeed enforceable in terms of regulation, it seems that traffic growth itself is directly linked with increasing prosperity. When mobility growth stagnates, this is usually due to a (temporary) economic recession. Also reaching a high level of congestion can lead to stagnation within a particular segment of the transport sector, e.g. in road traffic. Structural congestion may suppress autonomous growth, but particularly increases the pressure to guide the growth in another direction, for example by building more road infrastructure, through measures that improve the spread of traffic across the day, by increasing the capacity and the attractiveness of public transport, or by shifting the growth from commuter traffic towards the segment of recreational and tourist travel (including airplane use). 18

Introduction Overall, proposed policy measures aimed to reduce greenhouse emissions from traffic can be divided into four packages: 1. Steering mobility to a less car-dependent course by encouraging a modal shift towards alternative transport modes (other than passenger car or truck), a more efficient utilization of vehicles, but also substitution of transport by telecommunication. Known examples in passenger transport are: car sharing, carpooling, the provision of public transport, encouraging cycling and walking, and teleworking and videoconferencing (Robèrt and Jonsson, 2006). 2. Increasing, and possibly varying, financial charges on those types of mobility which emit most greenhouse gases, while alternatives may be supported in parallel. Examples in passenger travel are raising fuel taxes, introducing registration charges corresponding to the emission level of the vehicle, but also road tolls, smart charging, free public transport and bicycle allowances (Chapman, 2007). 3. Increasing vehicle efficiency by accelerating fleet replacement by more fuel efficient vehicles or vehicles that run on alternative fuels (including switching to renewable organic fuels, known as biofuels) (Anable and Bristow, 2007). 4. Intervening in the spatial structure through land use planning with the aim of bringing potential destinations closer together and making long distance transport needless. With regard to person mobility it is generally assumed that increasing density and developing a high degree of land use mix leads to less use of private cars and shorter daily distances travelled (Newman and Kenworthy, 2006). The latter form of proposed policy is the background of the research which is reported in this dissertation. The objectives of these four packages are clear, and throughout the western world many examples can be found where this kind of measures are implemented and measurable successes were reported. However, the finding that overall traffic and transport emissions continue to grow (Cervero and Murakami, 2010), leaves room for some healthy scepticism. Below, we give a number of concerns, again grouped by package. 1. In terms of modal shift many local success stories are known. An example is the historical centre of Bruges (Belgium), where in the period 1999-2004 car traffic in the city core declined under the influence of a rigorous mobility policy, while the number of cyclists and users of public transport increased considerably in the same period. The number of registered cars in the entire municipality (which con- 19

Chapter 1 tains six times more inhabitants than the old town), however, continued to increase. Thus, the success story remains very local, and led to a geographical shift in the growth of car traffic (City of Bruges, 2007). It is difficult, if not impossible, to find a clear example where a purposive mobility policy on a regional scale has led to a significant substitution of individual car use. Nevertheless, the finding that the modal split largely varies throughout the western world, depending on the city, the country and the general context, is promising for potential sustainability gains in mobility. 2. The main success story in terms of taxation is perhaps the London Congestion Charge, which has led two years after the introduction to a reduction in CO 2 emissions in the charged area by 19.5% (Beevers and Carslaw, 2005). Again, it may be assumed that a part of the suppressed traffic finds its way outside the demarcated charged area. Moreover, public support for additional charges on car use (also outside the city centres) is hardly present anywhere in the western world. 3. Anable and Bristow (2007) show that UK greenhouse gas emissions from cars remained almost constant in the period 1990-2005, while both the kilometrage and the average weight per vehicle increased significantly. So we are talking about a major rebound effect, where efficiency gains are associated with an increase in activity, and finally with a status quo of energy consumption. Indications exist that the rebound effect occurs at the macroeconomic level too, meaning that efficiency gains may lead to accelerated economic growth with an overall increase (instead of a decrease) in energy consumption (whether or not outside the transport sector) as a consequence (Saunders, 1992). Also, the effectiveness of the use of so-called biofuels has in recent years led to a major controversy (Righelato and Spracklen, 2007). 4. Although many studies have found that spatial structures with an urban character are associated with a lower per capita energy consumption for transport (Newman and Kenworthy, 1999), the correlation between density or spatial diversity and sustainability of travel patterns is in fact quite weak. One possible reason is a geographical form of the rebound effect. An increase in the choice range, manifested as a better internal accessibility which is typical of urban structures, will partly offset the relatively small mutual distances, making people less inclined to choose the nearest possible destination 20