This document explains how public money contributed to public-private partnership projects in the transportation sector should be analyzed. The aim is to justify these contributions by comparing the benefits to society with and without the public investment. Public funds should only be used if the benefits to society outweigh the costs. Reasons for public funding include supporting positive outcomes like less traffic congestion, offsetting negative effects that private companies might not consider, and funding essential network improvements for economic growth. The analysis aims to ensure that public money invested in these partnerships provides greater overall benefits to society.