Suggested Citation:
Shilling, Fraser M., Benjamin Hodgson, Carson Wong, Dana Lodico (2026)

Mitigating Highway Traffic Noise for More Effective Wildlife Crossing Structures

Traffic noise inhibits wildlife occurrence and movement within areas adjacent to roads. Wildlife crossing design and siting does not evaluate traffic noise impacts on animals that are the targets of these structures. Crossing structures must be designed to limit noise intrusion to effectively reconnect wildlife populations. We used three noise propagation programs to calculate traffic noise levels adjacent to proposed and actual wildlife crossings: 1) NoiseModelling, which follows the European standard (CNOSSOS-EU); 2) Traffic Noise Model (TNM, USDOT); and 3) CadnA, an environmental noise prediction software. We tested the models' performance in wildlife habitat near multiple highways using sound pressure level meters. We developed models (5 - 10 m resolution) of traffic noise intrusion into areas adjacent ( We found that modeled noise adjacent to wildlife crossings was consistently at intolerable levels for many species (>65 dBA). The computationally designed barriers reduced noise within and approaching the structures, creating quieter paths for wildlife to access ( < 5 5 dBA, tolerable to wildlife). Model comparison revealed some important differences in performance. We propose that this noise modeling approach will likely make crossings more effective for many species.