Disturbance from vehicle noise and human activity extends into the nearby habitat, creating a road effect zone. We aimed to assess how traffic volume and distance to the highway influenced mammal beta diversity within the road effect zone. We detected nearly all known mammal species larger than rodents in the study area, including all known carnivores (10 species). However, we detected fewer species around the high-volume road. Our study provides insights into the impacts of vehicle traffic on mammal use of road effect zones.