Progressive Public–Private Partnerships: Evidence from Two Case Studies on Convergence and Divergence in Collaborative Development

Abstract Progressive public–private partnerships (P3s) have emerged as alternatives to fixed-price P3 models in response to concerns about excessive risk transfer and the challenges of delivering complex transportation projects. Through a predevelopment agreement (PDA), progressive P3s introduce the development entity earlier, enabling collaborative scope refinement, iterative risk allocation, and a clearer pricing basis before committing to a long-term agreement. This study investigates progressive P3s through comparative case analysis of the Pennsylvania DOT (PennDOT) Major Bridge P3 Project (MBP3) and Maryland DOT’s Op Lanes Maryland Project, two initiatives that followed contrasting development trajectories. Using an exploratory case study design structured around four analytical dimensions and one inductively derived dimension—owner readiness and project preparation—the analysis examines how progressive P3 structures shape collaborative development and the conditions under which projects converge toward implementation or diverge during development. The MBP3 case illustrates how deliberate predevelopment program design, including an availability-payment structure and scope configured for adaptive delivery, created conditions for convergence despite significant institutional setbacks, although advancement was partial, with three of nine candidate bridges not advancing under the program. The Op Lanes case illustrates how unresolved institutional dependencies and a financial structure lacking adaptive capacity created conditions that collaborative development could not overcome, ultimately leading to orderly termination of the PDA. The comparison indicates that development-phase outcomes depend substantially on conditions established before collaborative development begins, that unresolved third-party dependencies become shared challenges for public agencies and developers once the PDA is executed because both parties are invested in advancing the project, and that governance in progressive P3s depends not only on contractual design but also on the public agency’s capacity to manage collaborative development. Five propositions are derived to guide future empirical research on collaborative development processes and outcomes in progressive P3s.