Facing rapidly increasing demand for new or additional transportation capacity, many states are eagerly exploring public-private partnership (PPP) in state highway development, which may allow public agencies to access private project financing and specialized expertise, and thus save public investment, expedite project completion, or improve service quality and diversity. Nevertheless, the path of PPPs is not smooth. The confusion and controversy surrounding recent asset-monetization leasing concession cases in the US have led to widespread public concerns and legislative caution, in particular on the question of whether a PPP project is advancing the public interest. The purpose of this project is to study the public interest associated with PPPs, with the goal to maximize efficiency gains, mitigate potential risks, and address public concerns in launching and deploying PPPs in state highway development. In particular, we focus on three aspects of PPP consideration: (1) Understanding economic rationales of PPPs, (2) Legal and political aspects of PPP decision-making, and (3) Managerial issues in implementing PPP projects.