Design Dilemmas in Long Term Foresight Studies

Design Dilemmas in Long Term Foresight Studies


Hans Hilbers, PBL Netherlands Environmental Assessment Agency, Danielle Snellen, PBL Netherlands Environmental Assessment Agency, Jan Ritsema Van Eck, PBL Netherlands Environmental Assessment Agency


Studying the future comes with many uncertainties and dilemmas. The paper sketches the choices faced in a long term transport foresight study aiming to provide plausible scenarios and a workable bandwidth for policy purposes.


In 2006 the PBL Netherlands Environmental Assessment Agency and the CPB Netherlands Bureau for Economic Policy Analysis published a scenario study exploring the long term developments relevant for welfare, prosperity and the quality of the living environment in the Netherlands. Since then these scenarios have been widely used in policy development and project appraisal. Over the years additional studies have been published increasing the regional level of detail.

Recent developments, both on a global and a national level, have prompted the demand for a new long term study, incorporating new insights and developments. The PBL and CPB are currently designing this new foresight study and will be carrying it out in the following year. Two scenarios on a national level will be developed, incorporating the main global developments influencing demographic and economic developments in the Netherlands and looking forward to 2050. In addition theme projects will add extra dimensions to the scenarios. The paper discusses the design dilemmas for the transport theme and the regional distribution & urbanisation pattern theme as it is a main contributor of information to the transport theme. Other themes are climate & energy and agriculture, nature & water.

In a scenario study forces researchers to make many choices. The study must give insight in the bandwidth of future developments following from uncertainties the future will hold. It is crucial to obtain the ‘right’ bandwidth. A bandwidth too small will soon be useless since it does not capture the oscillations in developments that will occur in the longer term, making policy based on it not robust. Especially when actual developments in the first years after the study move outside the projected bandwidth (which can easily happen with long term studies), the credibility of the study is compromised. A bandwidth too large will mean that in the highest scenario investments in transport and built environment will never suffice to satisfy demand and in the lowest scenario no investment will ever be cost effective. Another major issue in designing a foresight study is the way in which the study deals with policy. If the scenarios assume major policy shifts, the value of the study as a signalling device for policy relevant developments is reduced. Not incorporating policy is impossible, since a world without policy does not exist.

In order to obtain a workable bandwidth, the transport theme as distinguished six main uncertainties that need to be incorporated in the scenarios:
• Demographic and economic developments: what will be the potential developments in population and households (and their composition) and the number of firms and jobs (and their sector structure). For this uncertainty we will use the results of the two national scenarios.
• Spatial developments: depending on many factors population and jobs may concentrate or spread out within regions but also between regions. This distribution is crucial for transport needs and mobility patterns. This uncertainty will be developed in the regional distribution & Urbanisation patterns theme. Driving forces in this theme will be policy choices, residential preferences, regional economic developments, real estate market development etc.
• Changing behaviour: there are signs that travel behaviour is changing. New activity and travel patterns and modal preferences, for instance under influence of new information technology, will likely affect the demand for transport. The likelihood of peak car is part of this uncertainty.
• Energy use and climate policy: Developments in energy/climate policy will be crucial for the energy use for transport in the future. It may lead to a modal shift towards more energy efficient modes, which may have consequences for transport demand and maybe even urbanisation patterns. For this uncertainty we will build on the findings in the theme climate & energy.
• Technological developments: New modes of transport may influence transport demand. Examples of these are the growing impacts of electric bicycles in the Netherlands or the arrival of the self-driving car.
• Developments in network capacity, transport taxation and public transport tariffs: Choices policy makes with regard to these transport issues are crucial for future developments.

Combining different directions within these six uncertainties, we are now considering developing four scenarios. They will be different combinations of high or low economic/demographic growth, concentrating or sprawling spatial patterns, increasing or decreasing car shares in travel patterns, strict or lenient climate policy and a conservative or sustainable development of vehicle technology.

In the paper we will further elaborate on each of the uncertainties and the potential impact of different developments. In the session we would like to discuss our preliminary choices.


Association for European Transport