Modelling an Extension Decision of BOT Transportation Infrastructure: A Risk-Adjusted Approach

Thailand has a long history in welcoming the private sector to participate in the development of large-scale infrastructure projects through a program called public private partnership or PPP. Build-operate-transfer (BOT) and build-transfer-operate (BTO) are two of commonly used PPP contracts for transportation infrastructure, in which the private (or the concessionaire) is responsible for the risks relating to the design, finance, construction, and operation and maintenance (O&M) of the project. As some of PPP transportation infrastructure projects in Thailand are approaching its final year of a concession period, decision as to extend or to end the contract must be made by a contracting agency, that is: (1) to extend the concession contract to the existing concessionaire for a certain period of years or (2) to let the concession expire and to have a responsible public agency assume the operation. This paper is to propose a decision-making model based on a level of risk exposure as a computational tool for comparing between a renewal package offered by the concessionaire and expected benefits generated under the operation by the public agency. A case study project, a BOT elevated road located in Bangkok, will be used to illustrate the application of the proposed model. One of the implications of this study is that the estimated figure computed using the proposed method may be treated as a public sector comparator (PSC), which can be used as an initial benchmark for the negotiation with the existing or a new concessionaire.