The Road to Sustainability: Economic, Social, and Environmental Dynamics in Toll Road PPPs
- Tesis/Trabajos de Grado 
Several countries have embraced Public-Private Partnerships (PPPs) for reducing fiscal pressure on governments, allowing them to leverage on private sector¿s efficiencies by transferring finance, build, maintenance, and operation responsibilities to private partners. In turn, the private sector benefits from long-term financial returns, satisfying investors¿ and lenders¿ expectations. Moreover, an increasing number of governments have preferred user-pay PPPs for transferring the sources of funding to users and, consequently, reducing public sector burdens. The continuity of user-pay PPPs is based on guaranteeing their sustainability, which can be defined as the aggregation of their economic, environmental, and social dimensions. This dissertation, therefore, develops a comprehensive analysis of the main sustainability challenges of user-pay road PPPs through five interdependent studies. In the first study, the evolution of the PPP body of knowledge and the relationships between its main components is analyzed over the last two decades. Results demonstrate that the PPP body of knowledge has been traditionally driven by the economic dimension of sustainability neglecting the social and environmental dimensions, which should be strengthened to counterbalance the current pitfalls in social legitimacy and environmental underperformance to promote the emergence of more sustainable PPPs. In the second study, the relationship between PPP thematic keywords and sustainability is measured through the intensity of the link of PPP topics with the Sustainable Developing Goals and their targets. Findings confirm that the intensity of these relations is heterogenous. Overall, this study reveals that sustainability of PPPs only can be advanced in a holistic way if its three dimensions (social, environmental, and economic) are properly considered. For advancing the economic sustainability of PPPs, the third study model the relationships among the main financial drivers of toll road PPPs through a System Dynamics approach to formulate the concessionaire¿s life-cycle policies to achieve the financial sustainability of PPPs and avoid litigation and renegotiations that would harm the social legitimacy of PPP programs. Results reveal that there are two significant life-cycle measures that concessionaires should implement when addressing financial underperformance: early proactive improvements (CAPEX savings) and middle-term reactive actions (increasing debt repayment period). In the fourth study, the most significant challenges for achieving social legitimacy are exposed based on the analysis of two national toll road PPP programs. Findings revealed three significant groups of challenges that must be addressed to enhance social sustainability in user-pay PPP programs: social involvement issues, distrust between impacted and responsible stakeholders, and lack of social criteria within the toll tariff policy. The analysis demonstrates that social value creation and the impacted stakeholders¿ perception of such value also require more engaged forms of integrating impacted stakeholders in key making-decision processes beyond the traditional public consultation scope. In the last study, the main drivers of the effectiveness of Environmental Impact Assessment in toll road PPPs are analyzed by embracing a fuzzy set Qualitative Comparative Analysis. The results of the analysis of the 28 toll road PPP projects demonstrate that three external stakeholders are required for multidimensional EIA effectiveness: communities, environmental consultants, and non-preferred proponents. Overall, this dissertation contributes to the PPP body of knowledge by understanding the dynamics of the social, financial, and environmental drivers for sustainability in toll road PPPs. By implementing a combination of qualitative and quantitative research strategies, this dissertation describes, understands, and addresses sustainability challenges of toll road PPPs.