Identifying transport policy priorities through a meta-analysis of cost-benefit analysis in the Netherlands and Flanders

In this paper we assess cost-benefit analysis (CBA) reports and outcomes for transport projects in the Netherlands and Flanders between 2010 and 2024. CBA has been used extensively to evaluate potential investments in transport infrastructure, and to compare options. We investigate which factors contribute most to the Net Present Value (NPV) of CBAs and to what extent social, ecological and economic criteria are relevant to the outcomes of the evaluation. Results show that on average 80 % of monetized effects stem from economic criteria, whereas social (15 %) and ecological (5 %) criteria contribute far less to the outcome. This is also reflected in the finding that for 90 % of the cases the exclusion of social and ecological criteria does not change the outcome of the NPV calculation (from positive to negative, or vice-versa). Although sustainability is becoming increasingly important in the discourse around transport infrastructure, both social and ecological aspects of sustainability have only a minor impact on the NPVs and outcomes of CBAs for transport projects in the two territories and the time period under investigation. This implies that most transport investments do not specifically target sustainability issues, or that CBA does not reflect these considerations.