A wide variety of policy measures and interventions can be applied in order to promote efficient, accessible and sustainable transport systems. However it is widely recognized that transport systems are complex and their performance depends on multiple factors. It is therefore a significant challenge to ensure that policies actually lead towards their intended objectives, and to avoid unanticipated negative side-effects within and beyond the transport sector. One way to approach this challenge is to adopt integrated policy packages where measures supplement each other and compensate for expected negative effects of individual measures. A key element in a systematic approach for policy packaging must be to enable the identification in advance of non-intentional effects of individual or joint policy measures. This paper develops a typology of non-intentional effects of transport policy measures as part of a methodology for policy packaging in the OPTIC research project. The paper first establishes the need to address systematically unintended effects and then proceeds to unfold the dimensions of the typology with concrete examples along the way. Ways to use the typology is discussed in the final section of the paper.