Hans Hilbers, PBL Netherlands Environmental Assessment Agency, Danielle Snellen, PBL Netherlands Environmental Assessment Agency


For long term transport planning a new set of comprehensive long term scenarios is developed. They show that growth of transport demand is no longer a certainty. Handling this is a new challenge for transport planning.


Transport networks evolve slowly. Building new road or rail capacity is expensive and time consuming. Once in place, new infrastructure will have to last for decades. To make sure that money on infrastructure is well-spent, we need a good insight in what the future may hold. However, the future is uncertain. Population growth and the state of the economy can swing in different directions within the time frame of just a few years and as a result our forecasts of what the future may hold sometimes change faster than roads can be built.

In the study Prosperity and Environment (WLO) a new set of comprehensive scenarios is developed. They describe how developments in demography, economy, spatial distribution of jobs and people, technology, international climate policy and travel preferences lead to a bandwith for the development of mobility, accessibility, energy use and road safety. As not all uncertainty fits in only two scenario’s, additional sensitivity analyses show the potential effects of more uncertain developments. The set of comprehensive scenarios can then be used to evaluate the robustness of transport policies. For different types of policies, users will have to establish if the low and high reference scenarios sufficiently cover the relevant uncertainties. If not, the use of information from the additional sensitivity analyses is called for.

At the 2014 ETC conference we presented a paper on the wide range of uncertainties relevant for transport. In this paper we will describe the results of the scenario building process. We will discuss the scenarios for transport development up to 2050 and some of the additional sensitivity analyses. More importantly, we will explain how the assumptions on demographic, economic, technological and other developments have contributed to the end results. In other words: what shapes our expectations on future transport demand and transport impacts?

For decades, dealing with growth or transport demand was the main goal of transport policy. Our new scenarios will show that growth of transport demand is no longer a certainty for all modes in all regions. Handling this type of uncertainty is a new challenge for transport planning. The scenarios will be a tool for policy makers in this process. The study is expected to be published in october 2015


Association for European Transport