Public-private partnerships are not a new concept to transportation infrastructure development. For highways, the private sector historically had an important role in highway construction operation and financing. Although the role of the private-sector in highway financing and operation declined in the mid-part of the 19th century, in the late 1980's, private-sector involvement in these cases remerged. As Federal and State highway funding becomes more constrained, and as the need for highly efficient surface transportation systems continue to grow, the role of the private sector will continue to reemerge. This section will discuss the history of public-private partnerships in highway and transit development.