The slow implementation of sustainable innovations in the asphalt paving sector: the role of actors and their interactions

International climate agreements and government policies, push the road construction industry towards more sustainable practices using alternative materials, new production techniques, and more efficient construction processes. Despite the broad availability of these sustainable solutions, their adoption is slow and uncertain. The reasons behind this remain unclear. This study employs a system innovation perspective to analyze the process that leads to the implementation of sustainable innovations in the Dutch asphalt paving sector. By exploring actors' roles and their interactions at different stages of the process, we aim to identify key aspects influencing the pace and outcome of the innovation implementation process in the industry. The results highlight that (1) the asphalt paving sector is anchored in a project perspective that often overlooks long-term sustainability goals, (2) several key innovation roles are not fully fulfilled, and the absence of a coordinating role is leading to misunderstandings, and (3) monitoring at both the project and sector levels is lacking; there is no holistic assessment of the overall impact of innovations. Overall, the findings suggest that sustainable innovation processes in Dutch asphalt paving remain confined to the niche level, which can be overcome by redistributing actors' responsibilities, addressing the lack of system monitoring, and overcoming the project perspective could help address the challenges in the process.