Investigation of factors affecting sustainability in public-private partnerships for infrastructure projects

While public-private partnership (PPP) is an accelerator of socio-economic growth by leveraging private capital in response to the infrastructure demand-supply gap, they are intrinsically in conflict with justice at the intra-generational level regarding environmental sustainability. This conundrum is the result of basic contractual and procedural PPP frameworks, in which the private sector's limited focus on attractive financial opportunities and short-term capital returns creates infrastructure patterns that impede progress toward sustainable development. Consequently, the issue of sustainability in PPP projects still needs further exploration. This article investigates sustainability issues in PPP projects and advocates a shift in infrastructure procurement strategy that emphasizes adherence to sustainability criteria alongside capacity increase, with a focus on the roles that both the public and private sectors play. Beginning with an in-depth analysis of literature and semi-structured interviews, the study identifies 23 of the main factors influencing sustainability in PPP projects. These factors are subsequently further examined using a questionnaire and then subjected to statistical ranking and factor analysis. The results of the ranking analysis indicate that 12 of the 23 identified factors can be considered as having substantial influence on the sustainability of PPP projects, the most important of which are: "Considering sustainability considerations in bidding evaluation and supplier selection," "Proportion of public sector investment with sustainability," and "private and public sector awareness of sustainability." Moreover, the factor analysis categorizes these critical factors into three groups: (1) participation structure, (2) Project management, and (3) political-economic environment. The results emphasize the need for integrating sustainability considerations into the very fabric of PPP projects while highlighting the crucial role of effective project management and shared commitment of both parties to sustainability in driving sustainability within PPP projects. Moreover, promoting sustainability in PPP projects requires the creation of a safe and stable political environment. In addition to being a guide to improving the performance of sustainability in PPP projects, the findings of this study can be a valuable reference for future research in this field.