Assessment of Public-Private Partnership Models in Developing Bridge Infrastructure in South West Nigeria

Bridge infrastructure is essential for connectivity across river crossings that would otherwise isolate communities and disrupt trade routes. Public-private partnership (PPP) models have emerged as a pragmatic financing mechanism for bridge development where public capital is constrained. This study assesses PPP models applied to bridge infrastructure development in South West Nigeria, with case analysis of the Lekki-Ikoyi Link Bridge in Lagos and the planned Fourth Mainland Bridge project. A professional applied case study design was adopted, drawing on project documents, concession agreements, traffic data, and structured interviews with 20 infrastructure finance professionals, government officials, and civil society representatives. The study evaluates risk allocation arrangements, revenue models, value for money assessments, and stakeholder perceptions of equity and accessibility. Findings from the Lekki-Ikoyi Bridge case show that the toll-based PPP model has delivered reliable infrastructure and sustained maintenance but has faced public criticism over toll escalation and affordability for low-income users. The Fourth Mainland Bridge project review reveals challenges in reaching commercial viability terms acceptable to both government and private investors. The study recommends a hybrid PPP model incorporating viability gap funding from the state government, social toll concessions for low-income users, and an independent project monitoring mechanism to protect public interest. These findings contribute to professional practice in infrastructure PPP structuring across Nigerian states. Keywords: public-private partnership, bridge infrastructure, South West Nigeria, toll roads, infrastructure financing.