Long‑term monitoring in Banff shows the Trans‑Canada Highway’s network of overpasses, underpasses and exclusion fencing has cut wildlife‑vehicle collisions dramatically — more than 80 percent overall and, on fenced stretches, by up to about 96 percent for elk and deer — a finding the Yellowstone to Yukon Conservation Initiative reiterated in a recent blog post that bolsters local calls to keep funding and expand crossings in the Bow Valley.
Y2Y’s explainer summarizes decades of Parks Canada monitoring, noting cameras have recorded more than 250,000 wildlife crossings and that the system of 44 crossing structures (six overpasses and 38 underpasses) plus roughly 82 kilometres of fencing is linked to the large drop in collisions. Parks Canada’s own pages describe the same mitigation system and its long‑running monitoring program, which began in 1996 and has underpinned multiple technical reports and peer‑reviewed studies.
The claim isn’t just advocacy: a peer‑reviewed study published Oct. 19, 2022 used a before‑after‑control‑impact (BACI) design and confirmed large declines in collisions for common ungulates on fenced stretches of highway in Banff (Ford et al., Frontiers in Conservation Science). That paper reported collision declines of up to 96% for elk and deer in the study area, while explicitly noting that exact estimates depend on how background trends are accounted for and that effects vary by species.
Banff was an early test site for this combined approach. The underpasses and overpasses and continuous fencing were installed in phases beginning with highway twinning and were intensively monitored to test whether animals would use the structures and whether collisions would fall. Tony Clevenger of the Western Transportation Institute, a long‑time researcher on the project, has called the Banff work “Canada’s biggest conservation success story.”
The evidence arrives as the region adds new infrastructure. Alberta’s Bow Valley Gap project — the Peter Lougheed Wildlife Crossing east of Canmore — moved through construction beginning in 2022 and Y2Y reports the structure opened in June 2025; the NGO’s project page cites a roughly $17.5‑million price tag and early animal use. Local officials and advocates say the Banff data provide measurable results they can bring to provincial and federal funders when arguing for more crossings and for ongoing fence maintenance.
Studies and monitoring also include important caveats. The Frontiers paper and Parks Canada monitoring note that fence integrity matters — downed trees, burrows or gaps can let animals back onto the highway — and that large carnivores have not shown as clear a collision decline as ungulates, in part because predator collisions are rarer and harder to measure. Researchers also document a “learning curve”: some species took years to begin using new crossings regularly.
For drivers, the practical point is immediate: the mitigation system has reduced collisions enough to lower human safety risks and the economic costs tied to crashes. Researchers report that on high‑risk stretches the avoided costs can make crossings economically pay back within a few years. That economic case, paired with decades of field data from Parks Canada and academic studies, is likely to be central as the Bow Valley debates where and how to build the next crossings.
