National transport models are used in countries throughout Europe to inform policy making. Until recently, the UK has been a notable exception. Although in 1996 the then Department of Transport commissioned two parallel studies into developing a National Transport Policy Model and a Spatially Detailed Network Assignment Layer (Abraham et al, 1997), the recommendations of these projects were not followed through, probably because of the cost and concerns about data availability and ultimate feasibility. Experience elsewhere in Europe, notably in the Netherlands since 1985, has shown that it is indeed possible to create models at the national scale, which are of value in national and regional policy making. It is important to recognise that the ten or so models identified in a recent literature survey (HCG, 2000) are quite different in their form and detail, often driven by the original objective for building the model. Also, the models described in the main text are all subject to continuous development and improvement. Rather than a final product, national models are evolving with new computational technology, technical development and policy requirements. The aim of this paper is to describe how the modelling system used for the 1997 National Road Traffic Forecasts (NRTF) has evolved into a nascent national transport model. An overview is given of the model components and a focused programme of improvements covering the short and long term is outlined.
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