The Netherlands has encountered significant cost overruns and failures in complex infrastructure projects. To address these challenges, Rijkswaterstaat, the primary authority for soil, road, and waterway management, is shifting from large DBFM (Design, Build, Finance, and Maintain) contracts to simpler, risk-sharing models. This strategic move aims to make projects more predictable and manageable.

Andringa et al. (2022) examined this approach using the Complexity Based Risk Assessment Method (CBRAM), which ties project complexity elements to objectives through risk breakdown structures and registers, establishing causal paths among these components. Their study highlighted the need for broader application of CBRAM to validate its effectiveness.

This research explores how project complexity assessments can improve risk assessment in Dutch infrastructure projects using CBRAM. Through a literature review, case studies, and thematic analysis of semi-structured interviews, the study applied CBRAM to four project phases: Renovatie Krammersluizen (tender), Selectieve Onttrekking IJmuiden (construction), IJboulevard (evaluation), and Zeetoegang IJmuiden (maintenance). These applications revealed critical complexity-risk relationships and identified key project milestones and risk factors. The findings demonstrated that even with data not initially structured for CBRAM, the method could uncover significant insights into complexity-risk dynamics, enhancing project teams' communication and decision-making capabilities.

Interviewees provided further insights into the practical application and theoretical underpinnings of CBRAM. They appreciated the formalization of risk relationships, which supports strategic planning and resource allocation. The value of multiple complexity assessments, particularly during dynamic phases like tendering, was emphasized. Additionally, the potential for incorporating different perspectives on project complexity, including those of clients, was recognized.

The study recommends integrating the improved CBRAM+ model into the Dutch infrastructure sector's risk management toolkit, as it offers a valuable perspective on risk assessment. CBRAM+ emphasizes recording risk ownership, allocation, mitigating measures, and residual risks, and enhances communication about complexity-risk influences. It is also suggested that CBRAM+ be tested in projects to evaluate its performance and in contexts where clients and contractors collaborate to explore and share risks, such as in new contracting forms like two-phase or Bouwteam.