Project loans are one of the financial instruments widely used for delivering large infrastructure projects. Nevertheless, there is a lack of standardized procedures and quantitative methods for assessing the credit risk and determining banks total exposure. This article aims to fill this gap by presenting a methodological framework that can account for a unique risk factor in a toll road project developmentroadway network externalities. In other words, the developed framework accounts for the effect of the changes in the publicly owned transportation network on a privately owned toll road link. These changes can come in multiple ways, as the roadway expansion, signal optimization, or application of intelligent transportation system technologies; and their effects are considered using typical loan risk indicators (e.g., probability of default, losses given default) and the implied capital requirement under Basel II accord. Hence the presented model provides a direct link between transportation planning and engineering decisions and their financial implications. The application of the model is tested on a simple network example for which identification of the feeder and competing links was possible. The case study results indicate that strategic position of a toll link in a roadway network and the size of the marginal change in the surrounding network have a significant effect on the loan risk indicators and the implied capital requirement.