determination of concession period in build-operate-transfer projects using fuzzy logic

the build-operate-transfer (bot) projects are a popular method of privatization of public infrastructure development. there are several risks which might affect a bot project negatively. concession period is one of the most important decision variables in arranging a bot-type contract which should be determined considering the existing risks and uncertainties. a longer concession period is more beneficial to the private investor, whereas a prolonged concession period may result in loss for government investments. on the other hand, if the concession period were too short, the investor would either reject the contract offer or would be forced to increase the operation fees in order to recover the investment costs and to make a certain level of profit. in this paper, the concession period is determined using a new fuzzy logic based methodology. the proposed approach accounts for the existing risks and uncertainties. in the proposed methodology, the interests of both parties would be ensured and a win-win solution would be achieved. to evaluate the performance of the proposed methodology, the methodology was implemented in a highway project.