Achieving the sustainability goals of transportation Public-Private Partnership (PPP) projects in China remains a pressing challenge. Project governance mechanisms play a crucial role in advancing the sustainable development of such projects. This study examines how contractual governance, relational governance, and risk management influence the sustainable performance of transportation PPP projects. A quantitative approach was adopted, utilizing questionnaire surveys administered to professionals from both private and public sectors involved in transportation PPP projects in Sichuan Province. Data were analyzed using structural equation modeling (SEM). The findings indicate that contractual governance exerts a significant positive effect on both relational governance and risk management. Although contractual governance does not have a direct significant impact on sustainable performance, it exerts an indirect positive effect through two parallel mediating pathways—relational governance and risk management. This study offers new insights into optimizing governance mechanisms in transportation PPP practice to foster sustainable development. To enhance the sustainable performance of transportation PPP projects, the public sector should strengthen the foundational role of contractual governance and strive to establish an integrated “institutionalized and digitalized” risk governance system. Meanwhile, the private sector should proactively develop relational governance capabilities within the contractual framework, improving collaboration efficiency through regular joint coordination mechanisms and transparent information-sharing channels. Only by systematically integrating contractual governance, relational governance, and risk management can transportation PPP projects effectively achieve enhanced sustainable performance.
Yang et al. (Wed,) studied this question.