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Opinionvehicles; traffic disturbance (e.g. noise, lights and motion) reduces the quality of habitat near roads (e.g. [4]); and, for many species, roads are barriers to movement owing to physical obstacles, such as fences, or to a behavioral unwill-ingness of the animal to move onto the road surface [5,6]. The impact of roads on the movement of animals represents a decrease in landscape connectivity [7], and can lead to decreased habitat accessibility [8] and reduced gene flow [9,10]. Solutions for mitigating the effects of roads on wildlife mainly focus on the installation of wildlife crossing struc-tures (‘ecopassages’) to improve connectivity [11]. Many types of ecopassage have been proposed and built, but there is little research on which to base an informed evaluation of their effectiveness [12–15]. van der Ree et al. [11] reviewed 123 studies of ecopassage effectiveness and concluded that they contain little useful information for evaluating whether the ecopassages have mitigated the net [e.g. International Conference on Ecology and Trans-portation (ICOET), formerly ICOWET (‘W ’ for Wildlife)], but most has not been published in the primary literature. Therefore, in an era when most scientific results are widely available through the publication process, road mitigation research remains somewhat in the dark ages. There are two main reasons why most research evaluat-ing ecopassages has not been reported in the scientific literature. First, the research is mostly conducted in a specific applied setting in which information is desired for a particular wildlife crossing project. The government agen-cies conducting the work often do not have any interest, incentive or requirement to publish the work more broadly. Second, as discussed in the next section, these studies are frequently characterized by a lack of scientific rigor [11]. Case-by-case post-construction studies: lack of scientific rigor Studies of ecopassage effectiveness are frequently designed without consideration of other similar studies (partly owingCorresponding author: Lesbarrères, D