The report is the outcome of a study carried out by an OECD road research group on traffic control in saturated conditions in which thirteen countries participated. It highlights the effects of traffic congestion in terms of energy wastage, environmental nuisance and driver annoyance. Firstly, the phenomena of saturation, congestion and over-saturation are defined together with the control objectives, parameters and measures which need to be considered. Subsequently, the present state-of-the-art is assessed, focussing on those concepts and control strategies which are promising. Thirdly, particular attention is devoted to future research needs. A set of appendices provides the most recent information on traffic-actuated control models at isolated intersections, on-line models, off-line programmes, mathematical approaches and traffic corridor strategies. This international study shows how, with the help of modern computerised tools, the systematic application of traffic control strategies can improve the efficiency of existing road infrastructure and enhance its use. A new research approach is needed to improve the use of preventative and remedial control measures for saturated conditions within the framework of a balanced traffic and transportation policy. (A)
Abstract