In this study we report a review of scientific literature, published from the year 2000 to 2014, aiming to identify the current best practices in sustainability assessment, including planning, of transport infrastructures together with current issues and knowledge gaps. Sustainability assessments of transport infrastructures are slowly increasing around the world and the practices vary considerably. Current applied methods rely basically on Environmental impact assessment (EIA) or Strategic environmental assessment (SEA) procedures, which in turn often contain one or more procedures such as Cost-benefit analysis (CBA), Multi-criteria analysis (MCA) and Life cycle analysis (LCA). In several countries legal frameworks exist for sustainability assessment of transport infrastructures, for instance the EIA and SEA Directives in Europe. However, limitations of EIA and SEA are acknowledged in literature, although a few studies report improved sustainability assessments. Suggestions are also made in literature to introduce wider perspectives in order to consider sustainability aspects more properly, e.g. the inclusion of social indicators. Assessments aiming at the consideration of sustainability aspects and influencing the strategic planning of these complex systems are rare and methods are in their infancy. Key issues and knowledge gaps that are in need of being further addressed by research include the requirement to cover wider spatial and temporal scales, the consideration of cumulative and indirect effects and a more effective incorporation of stakeholders. Other highlighted issues are inadequate monitoring of project outcomes and the general lack of combination of knowledge from different knowledge fields.