Some of the first designated wildlife passages for small and medium-sized mammals in the province of Québec (Canada) were installed during the widening of the highway Route 175. The effectiveness of 18 passages and short fences on either side of the entrances was evaluated through continuous camera monitoring and roadkill surveys conducted over 4 summers (2012-2015). Most mammal species used concrete pipe culverts and wooden ledge culverts more often than concrete ledge culverts. Roadkill was significantly greater at fence ends than within fenced and unfenced sections, and was less in those fenced road sections (and around the associated fence ends) where wildlife passages were more frequently used. While the passages were successful in general, several species only used the passages infrequently or not at all, and further improvements are needed. Several recommendations are made concerning ways to improve the mitigation of the impact of roads on wildlife, and future monitoring and research.