Developing strategies for climate change mitigation and adaption implies integrating risk and uncertainty and addressing path dependency and irreversibility in policy formulations. Risk, uncertainty and irreversibility (RUI) are associated with both the climate problem and the transport policy arena and in particular those with longer time horizons.
The compounding risks and uncertainties in the transport policy arena implies that policies and investment decisions are based on imperfect and incomplete knowledge. Further complexities arises in a real world decision making, where there are possibilities of disagreements about the goals and/or means to achieve the goals and hence risk and uncertainty associated with the negotiated policy interventions.
Local decision makers face even greater uncertainties because projections tend to lose precision at finer scales—an inherent problem of downscaling from coarse, aggregate models. If decision parameters cannot be observed and measured, there is a demand for rethinking traditional approaches that assumes a deterministic model of the world in which the future is predictable.
Evidently, RUI has consequences for institutional arrangements, including the optimal allocation of responsibilities to the different levels of government in the transport sector.
An optimal path of climate strategies must take into account uncertainties about the benefits and costs of policies, as well as irreversibility and a multiplicity of actors. This does in turn generate a demand for flexibility and adaptability in planning.