The long-term issue in terms of infrastructure is a lack of maintenance. Governments do not invest enough in the maintenance of current infrastructure. The advantage of PPPs is that they establish agreements and a budget at the outset. That way, governments have no choice but to maintain an infrastructure.
If we are looking for evidence, we will surely talk about the collapsing bridges. There are two potential problems—a design issue at the outset or a lack of maintenance. For their part, PPPs try to tackle those two issues by integrating design into construction and maintenance, and by establishing a contractual way to proceed. Paying for the maintenance is the government's obligation.
All too often, the government will announce budget cuts and postpone the maintenance of infrastructure to some other year. However, that is not an option with PPPs.