Indicators and beyond: Assessing the sustainability of transport projects

Yannick Cornet

    Research output: Book/ReportPh.D. thesis

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    Credibly demonstrating actual progress towards a genuinely sustainable transport situation remains a challenge. A key problem is that the incorporation of sustainability in transport policy and planning at present is not systematic.
    A motivating assumption behind this thesis is that a transition toward a sustainable transport system will require strong support from decision-support processes and assessment tools that do not only adopt the language of sustainability, but fully integrate an explicit notion of sustainability in all of their conceptual, operational and procedural approaches. There is therefore a general need to improve processes, methods and tools applied in transport infrastructure decision making so as to make them more resonant to the needs of both current and future generations corresponding to the fundamental definition of sustainable development.
    The core focus of the thesis is on how to ensure project impacts in terms of sustainability are identified and become inputs to decision making.
    The benefits of increased mobility based on speed and capacity are significant and visible, creating a wide range of reachable activities for a great number of people. Negative externalities of transport systems such as accidents, local air pollution and noise have long been monetised and accounted for in conventional transport project appraisal. But the transport sector today (in Denmark, in the EU and globally) is also an increasingly large contributor to the two core planetary boundaries of climate change and biosphere integrity. Such wider, more complex and longer terms effects that are also external to local interests and market transactions are not only increasingly observed in transport but are also far less well accounted for. The risk here is that evidence-based decision-making becomes discredited, as was already found to be the case for high-speed rail appraisal in the UK, which is the most important case analysed in this thesis.
    This thesis contributes to the following three challenges: the overarching conceptualisation of sustainable development as an ethos for transport infrastructure policy, the operational specifics of impact assessment based on indicators and methods for their prioritisation, and stakeholder representations applied in assessment procedures, with a particular focus on creating a explicit ‘future generations’ viewpoint. The research takes a starting point in Sustainable Transport Indicator Frameworks (STIFs), then expands to decision-support processes and assessment tools, and finally explores issues relevant for the wider field of transport planning and decision-making.
    A main underlying concern of the research is to develop new thinking and assessment methods that bridge the techno-rationalist//instrumental approach of conventional impact assessment tools with a wider communicative planning rationality. This is needed because of the complex, dynamic and interdependent nature of transport planning and decision-making.
    This thesis draws from multiple research methods which are both qualitative and quantitative. For the conceptual work, I rely on purposive literature reviews, including extensive reviews on sustainability theory and the implication of this body of knowledge for sustainable transport, as well as a detailed review of selected literature on the topic of sustainable transport indicator frameworks. Case study work draws upon extensive desktop-based analysis of impact assessment reports and other publically available material about real cases of large transport infrastructure appraisals. The HS2 high-speed rail (HSR) project appraisal in the UK is used as a case study in three of the articles that compose this thesis, first because of the long tradition for comprehensive and open appraisal processes in the UK, and second for the significant wider environmental, social and economic impacts of the scheme, which is an opportunity to examine sustainability in the context of transport appraisal in more detail.
    The work specifically concerned with the elaboration of assessment tools and decision-support processes is based on an adaptation of multi-criteria analysis tools (MCA) and more particularly on the Multi-Actor Multi-Criteria Analysis (MAMCA) approach, which gives more prominence to the explicit integration of stakeholders in transport project appraisal. Empirical work was conducted ex-post and consists of structured interviews based on online questionnaires following standard MCA steps. Finally in order to complement the research I also conduct exploratory work consisting of face-to-face unstructured interviews and structured observation of passengers’ activities in actual high-speed rail trips in the UK.
    The first article in this thesis develops a metaframework for what should inform the analysis and eventually the design of STIFs. The article identifies and describes a total of 21 ‘metacriteria’ that are grouped based on the framework function they are contributing to. Going beyond indicators, this article led to examining in more detail issues related to prioritising sustainability impacts, capturing trade-offs in the long term, and informing strategic sustainable transport choices, which are also relevant for other assessment and decision-support tools.
    The second and third articles investigate the conceptual foundations and address the operational challenges in incorporating a sustainability viewpoint using multi-criteria analysis tools (MCA). The nested model of sustainability is found to be a useful approximation of strong sustainability principles when used as guidance for prioritising impacts. However a key contribution of these articles is the implementation of a ‘future generations’ stakeholder in transport appraisal processes, which in turn is proposed as a key feature for sustainable transport appraisal (STA) processes. One practical outcome of the research is a comprehensive list of project impacts for ex-ante assessment of large transport infrastructure projects like HSR. Structured interviews based on an online questionnaire are also found to be well adapted to the challenge of addressing biases in expert- and stalkeholder-based assessment methods. This approach provides a means to both address the need for quantifying and comparing complex impacts between various options, and to enable the systematic inclusion of stakeholders, therefore allowing for a level of reflexivity and ‘democratic renewal’ in appraisal processes.
    In the fourth article, the issue of trade-offs between the two interrelated issues of biosphere integrity and climate change is investigated in more detail, where it is shown that current state-of-the-art decision-support processes and assessment tools lack formal ways of dealing with complex impacts with local and global implications that unfold over long periods of time. And finally the last article is a more conceptual piece that adopts a critical view on the historic emphasis for minimising travel time in transport planning, and contributes to a better understanding of the value of travel time from a traveller’s perspective. The concept of reasonable travel time (RTT) is introduced, where travel time is reframed based on the traveller’s experience of time in a total door-to-door journey. It is expected that RTT could lead to different thinking about the effectiveness of future transport investments, which is particularly relevant in a technological age where the overall quality of travel time can bring positive outcomes without necessarly changing the quantity.
    Taken together, the articles and chapters that compose this thesis contribute to defining the emerging field of ‘sustainable transport appraisal’. STA goes beyond the instrumental approach of conventional transport impact assessment methods that attempt to reduce, measure and forecast impacts in a cool, dispassionate way. It does so by adopting sustainability as an explict goal based on first-order principles, by integrating stakeholder perspectives in the decision-making process, and by incorporating the interests of future generations. Moving from impact assessment tools to appraisal processes means refocusing transport planning on decision-support and decision-making, which are technical and political endeavours that cannot easily be separated.
    Original languageEnglish
    Number of pages226
    Publication statusPublished - 2016


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