Evolution of public–private partnership models in American toll road development: Learning based on public institutions' risk management

• There was a two-phase evolution of PPP models in American toll road development since the late 1980s, from a private development model to a collaborative partnership model.
• When project risks arose as a result of poorly addressed critical success factors for PPP, public institutions took risk management measures to better manage these factors, leading to changed PPP models for future projects.
• Public institutions should enhance PPP-related government capacity and build effective institutions and legal systems for successful PPP development.

Over the past few decades public-private partnership (PPP) models adopted by governments for infrastructure development throughout the world have evolved continuously. This article develops a dynamic framework which argues that PPP models evolve when some of the critical success factors (CSFs) for PPP are changed/improved over time based on project sponsors' risk management. The framework consists of four elements: CSFs for PPP, rising risks due to poorly addressed CSFs, the corresponding risk management to change/improve the CSFs, and consequently changed PPP models. Here, CSFs for PPP contain three aspects: external environment, internal project characteristics, and partnership-related factors. The framework is empirically explored with a multiple-case analysis of six toll roads developed in the United States since the late 1980s. The results demonstrate a two-phase evolution of PPP models in the studied context, confirm the theoretical framework, and find that public institutions' risk management can effectively explain the PPP evolution.