The roles and responsibilities of public and private sectors under traditional procurement are well understood by state DOTs, architectural/engineering firms, and contractors that are involved in the process. The introduction of a PPP changes the traditional roles of these entities in the development, operations, and management of transportation infrastructure. The public sector's goal is to provide a transportation infrastructure (and system) that is safe and improves user mobility, whereas the private sector's main goal is to achieve a return on investment. Because these goals may be in conflict, the public sector must ensure that the assignment of roles, responsibilities, and risk is done in a manner that protects the public goals.