Book excerpt: Just as our transport systems become more and more important to our economic and social well-being, so they become more and more crowded and more at risk from congestion, disruption, and collapse. Technology and engineering can provide part of the solution, but the complete solution will need to take account of the behaviour of the users of the transport networks. The role of psychologists in this is to understand how people make decisions about the alternative modes of transport and about the alternative routes to their destinations, to understand how novice and other vulnerable users can develop safe and effective behaviours, how competent users can operate within the transport system optimally and within their perceptual and cognitive limitations. The contributions to this volume address these issues of how the use of our transport systems can be improved by taking into account knowledge of the behaviour of the people who use the systems. Topics discussed include driver training and licensing, driver impairment, road user attitudes and behaviour, enforcement and behaviour change, driver support systems, and the psychology of mobility and transport mode choice. This work will be of value not only to psychologists but to all transport professionals interested in the application of psychology to traffic.