An important part of transport policymaking involves long-term decision making. On the one hand, decisions are taken now that will have significant, long-term consequences (e.g. building a road, railway line, or airport).On the other hand, long-term objectives might require near-term actions (e.g. traffic safety objectives, travel time reliability targets, environmental objectives). Since the future is uncertain, transport policymakers must take uncertainty into account in their policymaking (e.g., uncertainties about future external developments, future transportation demand, modal choices, and how these choices affect accessibility, environment, and safety). The way these uncertainties are handled is strongly related to assumptions one has about the future. In general, there are three broad categories of ways of dealing with uncertainty: ignore or reduce uncertainties, assuming that present trends will continue into the future; find policies that are robust across plausible futures, assuming that the future can be predicted well enough to identify policies that will produce favourable outcomes in one or more specific plausible future worlds; and implement adaptive policies, assuming that the future cannot be predicted. The first and the second approaches are commonly used in transportation policymaking. This limited handling of uncertainty might lead to policy failures, because not all relevant uncertainties have been considered in advance. For instance, the competition from low cost air carriers and price reactions of ferries were not taken into account in planning for the channel tunnel project,which resulted in a significant overestimation of the tunnels revenues and market position, with devastating consequences for the project. Demographic and economic developments are normally dealt with via scenarios, but other uncertainties, such as shifts in activity behaviour and related mobility, changing opinions on transport performance by crucial stakeholders, and trend breaks, such as technological breakthroughs, are not handled verywell if at all. As a result, decision making with respect to transport systems turns out wrong, is avoided, or becomes delayed (e.g. in order to perform more research or more pilot tests). An adaptive approach is suggested that motivates its relevance for long-term transport policy analysis andillustrates long-term adaptive policies for solving road, rail, and air transport problems. For example, assume that a country intends to introducea kilometre based charge in order to reduce road congestion (e.g. the UK or the Netherlands). The policymaker faces many uncertainties related to, amongst others: the future costs and capabilities of charging-technologies; the attitudes of actors and institutions, including acceptability of thepolicy by the public; developments with respect to road pricing in neighbouring countries as well as in the EU; details of the charge (e.g., will it depend on place and time, or on emission characteristics); behavioural responses of the road users; and derived revenues. Therefore it is impossible to develop a fixed blueprint for the policy and its implementation in advance. Waiting for these uncertainties to be resolved will delay implementation considerably. In such a case, an adaptive approach might prove helpful. In the first stage of an adaptive approach, a flat rate kilometre charge might be introduced. At the same time, an information gathering systemis set up that monitors how implementation is proceeding, and makes sure that needed policy interventions are taken in a timely and effective manner in case the original policy objectives with respect to congestion reduction are not achieved. Depending on future information about technology developments, acceptability, privacy issues, and other uncertainties, the rates can be adapted and differentiated and fixed car ownership fees can be lowered. Hence, in contrast to traditional approaches, by this adaptive approach implementation can start immediately. In addition, a framework is created for future actions that allow for adaptations over time as knowledgeabout road pricing uncertainties accumulates and critical events with respect to the implementation of road pricing take place. Using road pricing and other cases as examples, the successive steps of an adaptive approach are demonstrated. For the covering abstract see ITRD E137145.
Abstract