ABSTRACT
A large number of public–private partnerships (PPPs) have been awarded in the rail sector during recent decades, especially to develop new high-speed lines. However, a lot of these PPPs have failed. The main reason for the failures is well known: strategic behaviours that create an incentive for concessionaires or, more precisely, some members of the consortium acting as the concessionaire in order to make over-optimistic ridership forecasts. Such over-optimistic forecasting is often performed at the instigation of the local public authorities that support the project. The larger the project, the higher the risks that traffic will be overestimated (Flyvbjerg et al., 2006).
