Private investments are an important instrument for funding public infrastructure projects. Governments around the globe have been developing incentives for the participation of private investments in these types of projects by using instruments such as PPP (Public Private Partnership) and project finance. PPP instruments are contracts in which the Government agrees to provide future guarantees or options, and are used in order to efficiently allocate risks and resources. Accordingly, the transportation sector is a vast field for the use of these instruments. An important risk factor associated with such projects is the volume of traffic, which directly impacts the feasibility of the venture. This dissertation presents a proposal for making projects feasible, and analyses the MG-050 Toll Road case, the first PPP in infrastructure in Brazil. Additionally, this work proposes the modeling of a minimum traffic guarantee through a Real Option approach. The conclusion is that the Real Option Theory contributes positively for the feasibility of the project and reduces the payments made by the public sector.