This book presents research and experiences around private-sector involvement in all stages of transport-infrastructure investment. By looking at several countries, we can learn from each other and draw conclusions that are relevant for the decisions that will be made in the near future. Chapter 2 is an overview of research in the field. It outlines the main reasons the public sector is usually responsible for traffic infrastructure: user charges are not feasible or desirable, investments are large and long-term, and there is a need for coordination between investments. Chapter 3 describes Belgian experiences with Public-Private Partnerships (PPP), and more specifically Flemish experiences – there have been few projects on the national level. Chapter 4 collects experiences from the Scandinavian countries (Sweden, Denmark and Norway). All have some experience of PPP contracts, as well as other forms of performance (build-operate-maintain) contracts. Also, there has been an upsurge in interest for PPP contracting in all three countries.