Comprehensive highway public-private partnership (PPP) programs are relatively new to the United States and not widely used. Limited highway funds, unmet needs for new highway capacity, interest from private investors, and other factors have led to substantial discussion of PPP projects and programs at the State and Federal levels and implementation of projects in a few leading States. In contrast, some countries have extensive and, in some cases, long-term experience with infrastructure PPPs, particularly highways. This presents a unique opportunity to capitalize on the knowledge and experience gained in the international community, where tested policies and practices are in place. A desk study was completed to identify the countries with the most potential to provide relevant and current information on PPPs. Subsequently, a team of nine professional representing government, private industry, and academe visited Australia, Portugal, Spain, and the United Kingdom in June 2008 to collect and evaluate information about PPP programs and projects for highway infrastructure. The team met with representatives of the public and private sectors involved in PPP arrangements. The Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO) jointly sponsored this scan through the National Cooperative Highway Research Program (NCHRP).