Contract stability in European road infrastructure PPPs: how does governmental PPP support contribute to preventing contract renegotiation?

In the last decade a considerable number of PPP contracts in Europe turned out to be instable and were renegotiated. This paper studies which combinations of conditions in terms of macro-level business environment and governmental PPP support and at project-level (remuneration scheme, risk allocation, project age and contract duration) contribute to avoid contract renegotiation, by conducting a qualitative comparative analysis of twenty five European road infrastructure projects. Results show that although the broader macro-level business environment has a clear contribution, contract stability can benefit from an availability-based remuneration scheme and a well-developed governmental PPP support in combination with other conditions.