交通需求不确定性是制定收费道路BOT(Build-Operate-Transfer，建设、运营、转让)项目合同最大的挑战，而项目合同的柔性机制是处理交通需求不确定最有效的方法之一。目前有关柔性合同的理论研究仅考虑特许权期的柔性，而代表公众利益的公共部门与以盈利为主要目的的私人投资者的行为分歧也没有得到足够重视。本项目同时考虑收费道路项目的社会福利和经济效益产出，建立包含特许权期、通行费和道路容量等多个要素的合同柔性机制,应用帕累托改进(Pareto-improving)原理协调多利益相关主体的行为分歧,引进延迟策略(Postponement strategy)和基于需求学习(Demand learning)的动态定价理论分析最优柔性合同的性质和效率。通过本项目的研究，期望帮助公私部门遴选可行项目、降低项目风险、维持公私部门长期合作关系,为健全交通基础设施投资市场和政策法规提供科学指导。

Traffic demand uncertainty is one of challenges for designing the Build-Operate-Transfer (BOT) contracts of private toll roads. The flexibility of the contracts to a certain extent mitigates the project risk caused by the uncertainty. The previous studies focused on how to determine the flexible concession term via the trade-off between the net present value and cost of the project. The selection of combination of the multiple contract variables, such as, the concesion term, toll charge and road capacity, under demand uncertainty seldom attracts the attention of researchers. Moreover, in a BOT toll road project, the public sector cares about the social welfare gain of the project, while the private sector concerns about the profit return on his/her investment. Therefore, there is a discrepency between the two parties on the selection of the contract variables. The flexiblity will be introduced in the current proposal to deal with the demand uncrtainty for the BOT toll road project. The optimal flexible BOT contract including the concession period, toll charge and road capacity will be investigated to maximize the social welfare and profit of the toll road project, simultaneously. In addition, the Pareto-improving strategy will be adopted to resolve the discrepency between the public and private sectors. The postponement strategy and demand learning method are introduced to deal with the traffic demand uncertainty and analyze the properties and efficiency of the optimal flexible BOT contracts. This proposal tends to address these important issues in the development of private toll roads. The results can help potential private investors and the public sector identify under what circumstances, a highway BOT project is feasible and profitable, how to mitigate the demand risk, keep a long term and stable relationship between parties. Therefore, the proposed topic is helpful in theory and practice for the development of transportation infrastructures through capital market.