Abstract
Uncertainty surrounding the plausibility of predicted increases in traffic on the UK's roads highlights the need for an alternative to unconditional forecasting in transport planning. A scenario-based method, capable of dealing with this kind of uncertainty, is used to explore three alternative scenarios for the development of transport in the UK up to 2025. By analogy with long-term trends in energy efficiency, the analysis generates a workable interpretation of sustainable mobility which is translated into a quantitative target scenario for 2025. (Author/publisher).