This book argues that the issues surrounding sustainable transport constitute a new – post-modern – phase in transport policy and management. Achieving sustainable transport requires more than ”optimal” management of congestion and the effects on public health and the environment. Assessments of external effects, and their optimal levels, tend to be piecemeal, localized, and focused on a specific type of effect. Sustainability, on the other hand, is a comprehensive, forward-looking concept that encompasses the achievement of a state of society that is better overall; it requires a widened concept of welfare that includes environmental quality and social justice in both the short and long term. This book is organized into three sections, each discussing a major set of challenges to the transition to a sustainable transport system.