In an ever-expanding world, impacts of human activity on the global environment are inevitable. The construction of roads and other linear transport infrastructure leads not only to the destruction of habitats, but has long-term impacts on populations and biodiversity, including the introduction of edge and barrier effects, mortality of individuals in vehicle collisions, facilitation of invasive species dispersal, and numerous others. On the other hand, roadsides have been found to have positive effects on biodiversity, as they can constitute important habitats for some species. Previous studies have quantified negative or positive impacts of roadside habitats on select species or under select management regimes, but the grand picture of the importance of roadside habitats for biodiversity conservation remains unclear. In EpicRoads, a project by the Conference of European Directors of Roads (CEDR), we aimed to quantify impacts of habitats related to transport infrastructure (HTI) on a range of taxa through meta-analyses. We used an existing database from a similar project by the Swedish Mistra Council for Evidence-Based Environmental Management (EviEM), while expanding our search to include studies carried out in more recent years. We quantified HTI impacts on species richness, a community-level measure, and on population abundance, a population-level measure. HTI impacts are measured through variables like road presence (versus absence), distance to road, and different variables related to roadside vegetation and road-related disturbance. Results from the meta-analyses will be presented to give an overview of what has been found in the past 10 years regarding positive and negative effects of factors related to HTI on all taxa with sufficient data. One of our objectives is to enhance our understanding of the extent to which HTI can be beneficial for biodiversity conservation and how observed patterns vary among species and road types. Thus, the results of this study are relevant for making decisions on road construction and roadside management, as they offer a multi-species perspective regarding impacts of HTI. However, in addition, our study will identify important knowledge gaps that can direct future studies in road ecology.