We explore how benefit-cost efficiency and electoral support affect road investment decisions in Sweden and Norway. In Norway, neither benefits nor costs seem to affect project selection. In Sweden, civil servants’ decisions are strongly affected by projects’ benefit-cost ratios, with a stronger effect for more expensive projects, while politicians’ decisions are only weakly affected, and only for small projects. In both countries, governments tend to favour investments in regions where they enjoy strong local electoral support. Using cost efficiency as a final selection criterion seems to filter out many inefficient projects already at an early stage of the planning process. We argue that even if political decisionmakers are apparently mostly governed by other concerns than cost efficiency, civil servants at the administrations should not shy away from preparing efficient project suggestions for decisionmakers to choose from.