Intensive interaction with differentiated groups of stakeholders like local residents, the Port of Rotterdam, nearby municipality employees and various specialist (traffic engineers, landscape architects, civil engineers and ecologists) (I1)

To maintain constant stakeholder engagement and accurately identify underlying issues, as expressed concerns may sometimes differ from the actual problems (I1, I6)

Maintaining ongoing engagement with various stakeholder groups, including professional stakeholders, is essential not only during challenges but also when operations are running smoothly (I3) Mediation and Facilitation

Organized structured stakeholder workshops with clear time frames, rules of participation and pre-defined discussion topics (I1, I3)

Tailored communication inviting local knowledge to improve project design (I1, I6)

Having the adaptive room to incorporate stakeholder suggestions demonstrated a commitment to their perspectives, fostering trust in the decision-making process (I6, I3, I1)

Early, transparent dialogue building confidence among stakeholders (I3)

Effective facilitation turned protests into constructive discussion (I3)

The IPM team lead effectively transferred collective experiences from the planning to the implementation phase while serving as a critical liaison between internal and external stakeholders (I3)

Stakeholder protests about the tunnel were converted into concrete wishes through intensive early interaction, open dialogue, and adaptive project capacity, leading to design changes (second tunnel, lower junction) and growing trust

Used an interactive prioritization “game” (allocating 25 symbolic balls) to help residents decide on project order (I1, I3)

Through mediation of the IPM team, stakeholders with contradicting interests were able to adapt and negotiate solutions rather than cast aside the projects (I3)

Transparent discussion about resource limits and benefits fostered consensus (I1, I3)

Strategic support was secured by engaging top management in discussions and conducting further consultations, which strengthened their understanding of community needs and priorities (I1)

Regional governments, citizens and NGOs co-prioritized 30 quality projects using a “25 balls = 25 million” game, which led municipalities to add their own 25 million

Proactively changed the route and negotiated with landowners for nature compensation (I1, I3 I7)

Suspended the process temporarily to allow for comprehensive stakeholder briefings (I1)

The IPM team instilled confidence in upper management to take the risk of initiating contracting before the project's verdict, preventing further delays that would have resulted from awaiting the decision (I9)

The project team proactively created a nitrogen-compensation sub-project (grassland nature reserve) and updated plans before court rulings, avoiding delays and gaining several years of time

Leveraged established trust to quickly mobilize a solution without initially discussing cost disputes (I2)

The recognition that project progress took precedence over individual interests facilitated the effective resolution of issues without major obstacles (I8) (I5)

When unexpected soil pollution, truck traffic issues and budget shortages emerged, parties focused on solving them together (compensation, new land locations, extra funding) instead of blaming, relying on trust to keep schedule and project going

Engage top management and key stakeholders in discussions to revise and adapt the plan for better resource utilization (I5)

Engage in out-of-the-box thinking to deal with time and space constraints (I2, I4, I5)

The successful outcome was facilitated by the collective desire of all parties involved, ensuring that the interests of each stakeholder were addressed, which contributed to achieving desired outcome (I3)

The IPM team lead effectively communicated to all stakeholders that mutual dependence is essential, emphasizing the importance of maintaining strong relations (I5)

While changing contractual agreements carries inherent risks, the IPM team demonstrated increased efficiency through this approach, which ultimately convinced the ministry that it was the correct course of action (I5)

RWS, policy, and contractor accepted extra risk and worked around contract rules to use an available ship dock for tunnel elements, enabled by tight collaboration, a “what's best for the project” mindset, and alignment across stakeholder groups

Used established stakeholder relationships to reframe the situation (I3)

Developed a creative campaign (promotional signs, vouchers, community photos) to mitigate negative impacts (I3, I8)

Focused on turning disruption into an opportunity for community engagement, ensuring mutual benefit (I8)

To allow an unplanned 10-week local road closure, the team co-created a promotional campaign with affected retailers using joint branding, visibility and festive actions so access problems turned into relationship-building

Supporting one another during challenging times while avoiding transfer of risks between parties (I1)

Activated pre-scenario planning measures for rapid response (I9)

Coordinated a joint public–private problem-solving effort focused on solutions rather than assigning blame (I2)

Understanding that all the stakeholders are dependent on each other and trust one another to do what is best for the project (I1)

Public and private partners are able to think of the good of the project keeping their differences aside when a problem arises (I1)

Having a keen attitude to understand what are the ongoing problems and discuss as a team to find solution (I1)

During major immersion problems with the second tunnel element, the client and contractor treated it as a shared challenge rather than a blame issue, with the client offering help despite internal pressure, thereby protecting the partnership and project