Land-use impacts in transport appraisal

Standard cost-benefit analysis (CBA) does not take into account induced demand due to relocation triggered by infrastructure investments. Using an integrated transport and land-use model calibrated for the Stockholm region, we explore whether this has any significant impact on the CBA outcome, and in particular on the relative ranking of rail and road investments. Our results indicate that induced demand has a larger impact on the benefit of rail investments than on the benefit of road investments. The effect on the relative ranking is still limited for two reasons. First, the number of houses that are built over 20-30 years is limited in comparison to the size of the existing housing stock. Second, the location of most of the new houses is not affected by any single infrastructure investment, since the latter has a marginal effect on total accessibility in a city with a mature transport system. A second aim of this paper is to investigate the robustness of the relative CBA ranking of rail and road investments, with respect to the planning policy in the region 25 years ahead. While the results suggest that this ranking is surprisingly robust, there is a tendency that the net benefit of rail investments is more sensitive to the future planning policy than road investments. Our results also underscore that the future land-use planning in the region in general has a considerably stronger impact on accessibility and car use than individual road or rail investments have.