Assessment and Mitigation of Noise Impact to Ungulate Highway Permeability

Focus Area

Wildlife & Ecosystems


Natural Resources






Under 1 year

Research Idea Scope

Noise associated with highway vehicular traffic has long been recognized as contributing to wildlife avoidance zones adjacent to highways, where traffic may become a “moving fence” that creates an impermeable barrier to wildlife, as well as reduced habitat quality.  Considerable research has been conducted on factors that contribute to noise propagation from highways, including traffic volume and distance from the roadway, particularly for breeding songbirds.  However, very little research has been conducted on how noise impacts ungulate wildlife species such as deer, elk, pronghorn and bighorn sheep.  These species are typically more mobile than breeding songbirds and thus noise impacts may be more complex.  Further, much focus has been given to the construction of costly passage structures (e.g., underpasses and overpasses) during highway construction to facilitate passage and promote permeability across highways.  Yet noise associated with highway traffic and impact to wildlife may limit the effectiveness of such structures. In northern Arizona from 2002 to present, we have collected (and continue to collect) millions of Global Positioning System (GPS) relocations and thousands of highway crossings for over 400 individual animals accounting for 5 species of ungulates (elk, mule deer, white-tailed deer, pronghorn, desert bighorn sheep) on 6 different highways exhibiting a range of traffic volumes (State Routes 260 and 64, U.S. Highways 89 and 93, and Interstates 17 and 40).  We have cooperated with Arizona DOT in having permanent traffic counters installed along study sections at all 6 highways concurrent with past and ongoing GPS telemetry studies and have gained significant insights into the impact of traffic volume.  These highways encompass a wide range of broad vegetative/habitat types (coniferous forest, juniper woodlands, meadows, grasslands, desert, etc.) and terrains.  As such, the combined availability of GPS wildlife relocation and vehicular traffic data across 6 highways with various terrain and vegetative types presents an outstanding opportunity to add tremendously to our knowledge of noise impacts as well as developing strategies to minimize noise impact by applying terrain, vegetative and structural (e.g., noise walls, rubberized asphalt) mitigations. Proposed research will consider the role of vegetation and topography on the propagation of roadway traffic noise, in addition to traffic volume and distance.  These factors will be measured and analyzed to develop empirical noise models, and then will be correlated to wildlife GPS relocations and crossing patterns at the various highways.  The ultimate goal of this proposed research is to understand traffic noise impact on ungulate movements and to provide a noise/vegetation attenuation methodology and mitigations.

Urgency and Payoff

This proposed research has numerous benefits, including: 1) Adding considerably to our collective understanding of the relationship among traffic volume, noise propagation, vegetation and terrain on wildlife. 2) Addressing noise issues and research opportunities in a comprehensive, thorough and scientifically rigorous manner. 3) Allowing for the data-driven development of sound mitigations to minimize the impact of noise on wildlife, especially in association with wildlife passage structures. 4)Ensuring that costly wildlife passage structures attain their full degree of effectiveness in promoting passage and permeability. 5) Capitalizing on the prior investment/funding of key elements to the successful accomplishment and effectiveness of this proposed research, including GPS ungulate telemetry and traffic data collection. 6)Capitalizing on the diversity of ungulate species, highways, vegetative/habitat types and terrains involved to both maximize the “validity” and applicability of the research relative to a wide range of “real world” conditions and locations. 7) Promoting cooperation among all entities and agencies in collecting, sharing and disseminating this much-needed research that will promote improved highway safety from reduced wildlife-vehicle collisions (and reduced liability) and improved permeability for wildlife.

Suggested By

Norris Dodd / Jeff Gagnon, AZTEC Engineering / Arizona Game & Fish Department