Wildlife crossing structures and research

Banff National Park

Once it became clear that the Trans-Canada Highway in Banff National Park would require an upgrade from two lanes to four, we needed to determine how best to increase the size of the highway while minimizing effects on surrounding wildlife. We also hoped to curb the high rate of wildlife-vehicle collisions on the highway.

To help solve this problem, transportation planners and scientists came up with a two-fold solution:

  • Install fencing on both sides of the twinned highway to keep large animals from accessing the highway right-of-way. 
  • Construct wildlife underpasses and overpasses to connect vital habitats and help sustain healthy wildlife populations by allowing animals to cross under or over the highway.

Tracking animal movement at the newly constructed wildlife crossings was made a top priority. Such work has been on-going in the park since 1996; the longest on-going wildlife crossing research and monitoring program in the world.

Research and monitoring

With a total of 44 wildlife crossing structures (six overpasses and 38 underpasses), and 82 km of highway fencing, Banff National Park has the most wildlife crossing structures and highway enclosure fencing in a single location on the planet.

Since 1996, continuous research and monitoring of the wildlife crossing structures has contributed to improvements in subsequent phases of the Trans-Canada Highway Twinning Project. Through sound science, innovation and collaboration, Parks Canada has become a world leader in highway wildlife mitigations.

Most recently, Parks Canada is proud to have collaborated with the Western Transportation Institute (Montana State University), the Miistakis Institute of the Rockies, and the Woodcock and Wilburforce Foundations on research and monitoring of the wildlife crossings.

Frequently asked questions

Why do animals cross the highway?

Animals need to cross the highway to search out companionship, mates, food, shelter, and in some cases, to escape predators.

Do highway fencing and wildlife crossing structures work and do they reduce wildlife-vehicle collisions?

It took up to five years for some wary species, like grizzly bears, to start using wildlife crossing structures; however, most species are now using them to safely cross the Trans-Canada Highway (TCH). Since fencing and crossing structures were first constructed, wildlife-vehicle collisions have dropped by more than 80%.

Do animals prefer underpasses or overpasses?

Wildlife use underpasses and overpasses alike; however, when given a choice each species seems to have distinct preferences. Grizzly bears, wolves, elk, moose and deer prefer crossing structures that are high, wide and short in length, while black bears and cougars tend to prefer long, low and narrow underpasses.

Is use of the crossing structures by wildlife changing over time?

Yes. As wildlife populations fluctuate, the number of occasions individuals of a particular species use the crossings also rises or falls. We have also learned that some animals need time to adapt to new structures on the landscape. For example, overpass use gradually increased for grizzly bears, cougars, and wolves over the first five years of monitoring.

Does human use of wildlife crossings affect how animals use them?

Yes. When people use crossings, animals tend to use them less. Human use of overpasses is prohibited in Banff National Park.

How do small animals get across the highway?

Small and medium-sized animals, such as snowshoe hare, pine marten, fisher, porcupine, squirrels and voles, have different requirements for movement across the TCH. Pine martens, snowshoe hare and red squirrels used drainage culverts more often when traffic volumes were high, while coyotes used them less.

What is the greatest threat to healthy wildlife populations?

Road-kill has an immediate and direct effect on a population, easily seen within one or two animal generations. On the other hand, complete barrier effects (i.e. not being able to cross an obstacle like a highway) can take several generations to develop within a population. Barrier effects on a grizzly bear population may take as long as 50 years to measure and can have serious repercussions on genetic diversity and overall health.

How do we know where to put future wildlife crossings?

Over the years, information about where different species are most likely to cross the highway has been collected using:

  • radio telemetry monitoring
  • animal tracks in the snow
  • wildlife observations, and
  • road kill hot spots

Wildlife movement models were built using mapping software to predict the most likely locations for wildlife travel across the TCH based on topography and habitat data for five species (black and grizzly bears, wolves, elk and moose). Locations for future wildlife crossing structures were then identified.

Why are animals still occasionally killed on the highway?

Occasionally, individual animals do get into the highway right-of-way. Research is currently underway to test the use of “electro-mats” as an additional deterrent to wildlife at certain breaks in highway fencing. An electro-mat will provide a mild ‘sting’ to the paw, hoof or nose that touches it. While the shock does not harm the animal, it will hopefully encourage it to choose another path away from the highway.

10 quick facts about highway wildlife crossings in the park
  1. In response to growing traffic volume, concerns about motorist safety and highway-related wildlife mortality, the 82 km section of the Trans-Canada Highway in Banff National Park began to be upgraded from two lanes to a four lane divided highway in 1981.
  2. Having reached completion in January 2014, there are now 38 wildlife underpasses and six overpasses from Banff National Park’s east entrance to the border of Yoho National Park. There is also one underpass in Yoho National Park.
  3. Highway fencing in Banff National Park has reduced wildlife-vehicle collisions by more than 80% and, for elk and deer alone by more than 96%.
  4. Wildlife crossings are designed to connect vital habitats and allow safe movement of animals across busy roads.
  5. Banff National Park has the most numerous and varied wildlife crossing structures in the world. It also supports the world’s longest, year-round monitoring program and largest data set on wildlife mitigation.
  6. In 2012, eleven species of large mammals have been recorded using wildlife crossings more than 150,000 times since 1996. This includes grizzly and black bears, wolves, coyotes, cougars, moose, elk, deer, bighorn sheep, and more recently wolverine and lynx.
  7. There is a "learning curve" for animals to begin using wildlife crossings after construction. For wary animals like grizzly bears and wolves, it may take up to five years before they feel secure using newly built crossings. Elk were the first large species to use the crossings, even using some while they were under construction!
  8. Research has shown that grizzly bears, elk, moose and deer prefer wildlife crossings that are high, wide and short in length, including overpasses. Black bears and cougars seem to prefer long, low and narrow crossings.
  9. DNA-based research is exploring how crossing benefit species such as bears and wolverine. DNA hair samples are collected using barbed wire strung at crossings or at strategically placed “hair-snagging sites” on the broader landscape.
  10. Parks Canada is a world leader in the use of innovative highway wildlife mitigations based on sound science and collaboration with leading experts and organizations in the field of road ecology.

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