Taxonomy of risks in PPP transportation projects: a systematic literature review

Despite the existence of previous studies on risks in Public Private Partnership transportation projects, there is still absence of an overall risk catalogue, common terminology and consistent risk structure. This research provides comprehensive risk inventory, harmonious language and taxonomy for risk classification. A systematic literature review was conducted that resulted in 72 recent articles. The Concept-driven and the Grounded theory approaches were combined for the qualitative data analysis. As a result, 86 unique risks were identified and grouped according to the phase of the project life cycle they are likely to occur. As obtained from the analysis, the most frequent risks in literature are 'low traffic demand', 'escalation of operation-maintenance cost', 'inflation rate fluctuation', 'problems with land acquisition and compensation', 'change in laws and regulations' and 'interest rate fluctuation'. The proposed terminology and taxonomy appear to be appropriate and provide an overall understanding of risk identification and classification as well as improve the effectiveness of communications for both PPP practitioners and academics in this area.