Maps as a Decision-Support Tool in Rail Transport Policy Formulation in UK

This paper describes the use of maps to support decision-making in the formulation of national rail transport policy in the UK. The shift from input-based to output-based policies created a need within government to determine feasible combinations of interventions that would deliver the desired outputs. This enables government to be an informed investor and buyer of services from industry. Rail models are used to estimate, for given interventions or combinations of interventions, the future values of the outputs of interest to government. Model outputs are voluminous so it is often difficult to appreciate, across the network, the impacts of interventions on the outputs at any reasonable level of disaggregation without some form of visual display of their values. Network maps of these outputs were therefore created and used in an iterative process of: identifying problem areas from visual display of current values of the outputs; designing options to address the problems; testing in the model and developing new outputs; mapping new outputs; and comparing with original maps to understand changes and see how well problems had been addressed without creating new problem areas. Combining traditional rail modelling with mapping provided a strong visual analytical tool for advising policy formulation. The Department of Transport's experience with this has encouraged and established the routine use of maps as aids to decision-making in national rail policy formulation.