Is a logical structure needed?

In Section 4, we argued that a practical approach to decision-making, between the extremes of rational analysis and “muddling through” was needed, and suggested three types of approach: vision-led, plan-led and consensus-led. We also indicated that most cities use a mix of these approaches. In the extreme, a vision-led approach does not need a logical structure for its development. The vision is clear, and all that is needed is to implement it. However, few cities can rely solely on such an approach. Where any element of the plan-led approach is involved, it is important to have an agreed sequence for the process. Where a consensus-led approach is adopted, the logical structure allows consensus to be reached at all the stages raised in Section 5.We make no excuse, therefore, for suggesting a logical structure which should help all cities to develop their strategies in a convincing and defensible way. While this part of the Guidebook is therefore prescriptive, the structure which we recommend still permits considerable flexibility in the decisions taken at each stage.

What is the logical structure?

The diagram opposite presents the logical structure. In it:

  • A clear definition of objectives & indicators is the starting point
  • They are used to define problems, now and in the future
  • Scenarios can be used to identify alternative futures
  • An alternative is to start with identifying problems, while checking that all objectives have been covered
  • Possible instruments are suggested as ways of overcoming the problems which have been identified
  • Barriers to implementation will arise for certain policy instruments
  • Strategies are developed as combinations of instruments, packaged to reduce the impact of the barriers
  • The impacts of the individual instruments or the overall strategies are then predicted using a model
  • The results for these options are then compared using an appraisal method based on the objectives
  • This process may well identify ways in which the instruments or strategies can be improved
  • It is possible at this stage to use optimisation techniques to help identify better strategies
  • The preferred instrument or strategy is then implemented, and its performance assessed against the objectives; these results may help improve future predictions
  • On a regular basis, a monitoring programme assesses changes in problems, based on the objectives


The logical structure

Why are all these steps necessary?

This process may seem somewhat idealised, but it has several virtues. It provides a structure within which participation can be encouraged at all the key stages in decision-making. It offers a logical basis for proposing solutions, and also for assessing any proposals suggested by others. If the answer to the question “what problems would this strategy solve?” is unconvincing, the solution is probably not worth considering. It ensures that the appraisal of alternative solutions is conducted in a logical, consistent and comprehensive way against the full set of objectives. It provides a means of assessing whether the implemented instruments have performed as predicted, and therefore enables the models used for prediction to be improved. It thus provides the essential source material for our Policy Guidebook. Finally, regular monitoring provides a means of checking not just on the scale of current problems, but also, through attitude surveys, on the perception of these problems.

How closely is this structure adopted in practice?

It is important to stress that few cities follow this logical approach in its entirety. This is clear in the four case studies which we present in Section 16. However, where they have not done so this has often led to weaknesses in their overall strategy:

  • Policy instruments suggested without being clear which problems they would overcome or whether they are the best solution
  • Strategies developed without considering the likely barriers to their implementation
  • Appraisal against selected objectives, thus overlooking some adverse impacts
  • Implementation without checking afterwards whether the strategy is operating as planned

It is to avoid these pitfalls that we recommend that the full sequence be followed where possible. However, a few elements are optional; we identify these in later sections.

The structure which we advocate matches closely that proposed by DGEnv for Sustainable Urban Transport Plans, as shown in the diagram, which also indicates the linkages with citizen and stakeholder participation and with wider urban strategies.

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Text edited at the Institute for Transport Studies, University of Leeds, Leeds LS2 9JT