Road Ecology Center

Based on an analysis of current literature, we developed a Traffic Volume Wildlife Tool that identifies different levels of traffic volume as a means to assess risk to various wildlife species groups, including amphibians, reptiles, birds, and mammals. Each level includes an assessment of when impacts to different species groups begin and when they become a serious threat. Traffic volume, or the amount of traffic using a road, poses substantial negative consequences for many wildlife species, especially as traffic levels increase. Road location and traffic volume are the two most important factors to assess when evaluating a road‘s potential impacts. Increases in traffic volume alter species composition, impedes animal movement, causes direct mortality, and fragments habitat. Based on the existing studies that quantify traffic volume and measure impacts to wildlife, we developed guidelines for use in planning. We discuss how changes in traffic volume affect habitat quality and animal behavior, and which types of species are most vulnerable. We recommend using these data and guidelines in land use and transportation planning and permitting.