The sustainable development of large transport infrastructure projects is vital to addressing societal challenges such as climate change, biodiversity loss, and urbanisation. In the Netherlands, the MIRT framework (Multi-Year Programme for Infrastructure, Spatial Planning and Transport) structures the planning and decision-making process for such projects. The exploration phase of the MIRT process is particularly critical, as it is where strategic ambitions are translated into project objectives at relatively low cost and high influence. Yet large transport infrastructure systems are complex socio-technical systems, which makes embedding sustainability in their early stages challenging. Complexities are not only caused by technical or innovative constraints, but primarily because of divergent stakeholder interests, organisational complexity, and financial and spatial limitations.
This research examines how sustainability is defined, debated, and embedded in MIRT explorations, and how the process can be structured to safeguard ambitions. It describes two case studies: Station Dordrecht and the Amsterdam–Haarlemmermeer (OVAH) connection. Using a combination of a literature review, document analysis and expert interviews the study traces how sustainability is operationalised in practice. The findings show that sustainability is a normative and context-dependent concept, interpreted differently across cases. Its definition and integration are strongly shaped by site-specific conditions, the scale on which the project makes impact, and the organisation of the process of embedding Sustainability. The study also identifies 24 influential factors across 10 themes that affect the successful integration of sustainability considerations.
Building on these insights, the research proposes a toolkit that reconceptualises sustainability in large transport infrastructure projects as an organising principle rather than a separate goal. The shift in perspective is based on three key insights: first, sustainability is inherently normative, shaped by the values and institutional contexts of the actors involved; second, the use of the label “sustainability” to refer only to a limited set of themes does not do justice to the multidimensional nature of the concept. This narrow framing can lead to misconceptions about what sustainability truly entails within a project context; and third, despite divergent interpretations of the concept, consensus and a converged understanding can be achieved when the process of embedding sustainability is approached in a structured and systematic way.
The toolkit translates these insights into practical guidance for embedding sustainability in governance structures, assessment frameworks, and decision-making processes. By organising the MIRT exploration itself as a sustainable process, projects can anchor sustainability within project logic and ensure it becomes an integral and lasting component of Dutch infrastructure planning. ... Read more

The construction sector significantly impacts the environment, with challenges including high carbon emissions, resource depletion, and waste generation. Renovating aging infrastructure in the Netherlands intensifies these challenges while presenting opportunities to integrate Sustainable Material Management (SMM). SMM focuses on optimizing material use across its lifecycle by reducing waste, improving recycling, and enhancing resource efficiency while balancing environmental and economic sustainability. This thesis explores how contractors can effectively implement SMM practices in Dutch infrastructure renovation projects. Through a structured methodology encompassing a literature review, semi-structured interviews with eleven industry professionals, and synthesis, the study identifies barriers, drivers, and actionable strategies for SMM adoption. Key challenges include financial constraints, client resistance, and limited access to sustainable materials. However, the study also highlights drivers such as regulatory incentives, technological advancements, and increasing industry awareness. The findings emphasize the critical role of contractors in promoting sustainability by influencing material selection, procurement processes, and construction methods. Recommendations include early contractor involvement in project design, flexible contracts to support innovation, adoption of digital tools like BIM and RFID, and collaboration across stakeholders. These strategies enable contractors to reduce environmental impact, improve economic performance, and align projects with circular economy principles. This research provides a practical roadmap for integrating SMM into renovation projects, supporting the Dutch construction sector's transition towards a more sustainable and resilient future. ... Read more

Governments worldwide are planning car-free policies to increase the livability of cities. However, car-free policies often face opposition from local stakeholders, and policy-makers often lack relevant model indicators to represent all stakeholder interests in their ex-ante car-free policy evaluations. Well-being (Dutch: Brede Welvaart) indicators can be more relevant for the various stakeholder interests in car-free policies by covering aspects in the domains of living environment, accessibility, safety and health. This thesis investigates how relevant well-being indicators can be selected and operationalised for the ex-ante evaluation of car-free policies. A well-being indicator selection process was developed and applied to a case study in the Oude Westen neighbourhood in Rotterdam. This process involved conducting thirteen semi-structured stakeholder interviews. The resulting stakeholder interests were analysed to determine the relevant aspects of well-being and the relevant indicators for these aspects. From the shortlist of relevant indicators, three indicators were selected and operationalised in this thesis. At last, two validation interviews were conducted to validate the results of this case study and the developed indicator selection process.

The most relevant stakeholders - municipality, local residents, and local business owners - were selected to be involved in the well-being indicator selection process in the case study. Based on their interests, the most relevant aspects of well-being were found to be the use of space, accessibility of mobility options, accessibility of activities, traffic safety, and noise pollution. This resulted in the operationalisation of three indicators: the use of space for car parking, the number of mobility options, and the traffic mix safety warning.

While the small sample size does not allow for generalisation of the case study results, the results of this thesis do show that the well-being indicator selection process can yield relevant indicators of well-being and that this process can be applied in practice. The operationalised indicators can be relevant to represent stakeholder interests in car-free policy evaluation and can be applied to other cases as well. However, the relevance of the indicators does depend on the type of policy and the stage of the planning process. Using well-being indicators in policy evaluation can enhance the relatability of the evaluation results for stakeholders and potentially increase stakeholder support for policies. ... Read more

The existing high level of greenhouse emissions and raw material consumption are the current concerns in the infrastructure sector. On the other hand, the programs for renovating the aged and overloaded infrastructures are currently under progress as substantial national programs with circularity targets in the Dutch context, involving various public-private networks. Implementing the circularity strategy of re-use in conducting the infrastructure projects will be beneficial to reduce the amount of emissions, minimize the raw material consumption, and facilitate the formulated national programs. Currently, there are just a few re-use projects, and running a higher number of these projects and accelerating the re-use transition in the infrastructure sector are urgent topics in the global and Dutch context. Public client organizations (PCOs) have determining role in this regard, as owners and commissioners of infrastructure projects. There are wider networks of actors and extra stages to follow in re-use projects, which can create barriers and make the organizational aspects of these projects extremely important. Most attempts are locked at the tactical level of PCOs, and a gap has emerged between the tactical and operational levels of these organizations in the implementation of the re-use strategy, which prevents acceleration of the re-use projects. There is less attention in the current studies to the existing gap between the tactical and operational level of PCOS in conducting re-use projects in the infrastructure sector, the required procedures to fill that, and accelerating the re-use transition, which are zoomed in and investigated in this research. The research is conducted through a qualitative method, following three different phases of theoretical study, empirical study, and solution development in the context of a PCO. This research recognized that the existing gap between the two levels is rooted in different fields, and the most urgent ones have been identified. It revealed that tackling such gaps requires following specific organizational procedures by actors within each of the two organizational levels and between them. Following such procedures to deal with the addressed gaps can be easier through using a framework. The required framework, provided in this study for public clients including organizational procedures and their relevant re-use implementation factors embedded in certain categories. Among the existing gaps in practice, three gaps are recognized as the most urgent ones, which are placed in the two top categories of ‘culture, communication and behavior’ and ‘contract, manuals and guidelines’. The top three gaps addressed by three re-use implementation factors of ‘target formulation, follow-up & evaluation’, ‘internal & external communication’, and ‘collaboration with external parties’. The provided organizational procedures are interrelated in implementing the re-use strategy, and the result of implementing some procedures should be followed by the work of actors at the same or another level. The strategic level should also intervene to fill the gaps specifically in formulating and re-visioning the targets. Structuring the communications, collaborations, and target formulation stages through implementing the procedures recommended in the presented framework in this research, and consistency with that, will prepare the organizational context, and link the tactical and operational level of PCOs in implementing the re-use projects. As a result, the re-use activities at the operational level of public client organizations will be more structured. With well-linked tactical and operational level and structured re-use activities, the re-use transition will be facilitated and can be accelerated at the operational level of the public client organizations. To address a circular solution for the national programs of renovating infrastructures, the active networks in them can consider the networks as the national context for re-use transition, and customize the framework to structure the inter-organizational procedures between the involved parties in the tactical and operational transition levels. Through structuring collaborations & communications between tactical and operational parties, developing clear and detailed targets, and evaluating them, the re-use transition can also be accelerated on the national scale. ... Read more