Accounting for Wildlife-Vehicle Collisions in the EIA Process

by Matthew Hawco,

Along the vast, ever-expanding stretches of Canadian highways, the health and lives of animals are constantly being threatened by collisions with motor vehicles. Wildlife-Vehicle Collisions (WVCs) are a surprisingly frequent yet preventable occurrence in Canada that can exact a great toll on wildlife populations and humans alike. Although awareness over the issue has been growing1, there is still a noticeable nation-wide trend for increasing WVCs with an estimated annual rise of 7.55% based on data from 1994-20042. The following illustration depicts collision rates broken down by Canadian jurisdictions and large animal type1:

Wildlife-Vehicle Collision rates displayed per Canadian Jurisdiction.

In almost all cases the rates of WVCs have risen by a significant degree and are likely to continue unabated with growing traffic volumes and expanding transportation infrastructure. While this trend poses a threat to many species and biodiversity in general, it is especially foreboding for endangered species with smaller populations, itinerant species, or those that are attracted to roadways for their heat or salt1. A rise in WVCs also presents concerns for public health and safety where collisions can result in human injury and even death, especially when larger mammals like ungulates are struck by low-lying vehicles3. Aside from these immeasurable costs, collisions and wildlife roadside mortality incur financial losses too through vehicle repairs, insurance claims, and highway maintenance and clean-up. Cumulatively, these impacts are estimated to cost upwards of $200 million per year1.

Faced with this compendium of grim outcomes, it is clear that Canadians must take steps to ensure that this problematic phenomenon is addressed at its source. One of the most opportune solutions then is to act upon roadway development before it begins and incorporate WVC prevention into transportation infrastructure plans. This approach is best realized through the process of an Environmental Impact Assessment (EIA) where the environmental impacts of a transportation project would be first identified in the initial planning phases and then intentionally circumvented or minimized during development. With regard to WVCs, there are several measures through which they could be mitigated or outright remedied in an EIA. First, roadways could be planned away from identified or predicted road-kill hotspots4 and ecologically sensitive areas. Second, as inexpensive measure, roadways could be built with additional wildlife signage, reduced speed limits, or roadside verge, while public awareness programs could also be affected34. Third, as a more permanent yet expensive measure, mitigation could be achieved through the creation of culverts, highway barrier fencing, or wildlife corridors such as overpasses and underpasses34. While each measure has its strengths, permanent strategies such as wildlife corridors have been shown to be quite effective in reducing WVCs, where areas like Banff have experienced a drop of 80% in ungulate collisions3 after the construction of a wildlife overpass (pictured below)5.

Wildlife overpass located at Banff National Park.

The implementation of these mitigation measures is most cost-effective when integrated into a project’s development plans at its early stages; however, measures such as wildlife corridors can still be accommodated into existing infrastructure post-commission. As an example, the Kootenay National Park issued the construction of three wildlife corridors along Highway 93 South in 2013 to address the increase of local WVCs. Below is a time-elapsed construction of one of these wildlife underpasses:

Despite the effectiveness of wildlife corridors though, there are still barriers which challenge their successful integration into planning and implementation processes. One of the main challenges can arguably be traced to the federal government which in 2012 established strict time limits for the duration of assessments in its revised Canadian Environmental Assessment Act6. With such stringent time limits, the accuracy and extent of collected data regarding a species’ seasonal migration patterns or home range will be compromised, consequently impairing our ability to predict possible mortality hot spots and best locate mitigation measures against WVCs.


1 Traffic Injury Research Foundation. (2012). “Wildlife-Vehicle Collisions in Canada: A Review of the Literature and a Compendium of Existing Data Sources.” Ottawa, ON: Vanlaar W.G.M., Gunson, K.E., Brown S.W., & Robertson, R.D.

2 L-P Tardif and Associates Inc. (2003). “Collisions Involving Motor Vehicles and Large Animals in Canada. Final Report.” Ottawa, ON.: Authors unknown.

3 Mountrakis, G., & Gunson, K.E. (2009). “Multi-scale spatiotemporal analyses of moose–vehicle collisions: a case study in northern Vermont.” International Journal of Geographical Information Science, 23(11). 1389-1412.

4 Langen, T.A., Gunson, K.E, Scheiner, C.A., & Boulerice, J.T. (2012). “Road mortality in freshwater turtles: identifying causes of spatial patterns to optimize road planning and mitigation.” Biodiversity and Conservation, 21. 3017-3034.

5 Samson, S. (2013, October 4). Cohabitation in Banff National Park [Article]. Retrieved from

6 Canadian Environmental Assessment Agency. (2012). Canadian Environmental Assessment Act, 2012 ( S.C. 2012, c.19, s.52). Retrieved from