Benefits of Reducing Collisions | Costs of Collisions | Case Studies

Costs & Benefits of Highway Mitigation for Wildlife Outside Protected Areas

Benefits of reducing wildlife-vehicle collisions (WVCs)

There are many benefits provided by mitigation measures aimed at reducing WVCs, such as fewer motorist accidents that may cause human injuries, deaths, and property damage.

Benefits to wildlife include protecting individual wildlife from death or injury, keeping populations intact, and allowing individuals free movement to access important habitats and resources, thus enhancing long-term survival and population viability.

A review of thirteen different mitigation measures used by transportation agencies - such as warning signs, vegetation removal, fencing, wildlife crossing structures - to reduce WVCs (Huijser et al. 2009) indicated estimated effectiveness can vary from as low as a 26% reduction in WVCs (seasonal wildlife warning signs) to a 100% reduction in WVCs (elevated roadway).

Each mitigation measure has a different cost to implement and maintain and thus the selection of the appropriate mitigation measure should take into account the different safety and conservation goals as well as its effectiveness in reducing WVCs.

Direct monetary costs of ungulate-vehicle collisions

Huijser et al. (2009) summarized the costs of the most prevalent group of ungulates - deer, elk, and moose - that are the source of over 90 percent of wildlife-vehicle collisions in North America (Table 1).

Table 1: Summary of the monetary costs (2007 US Dollar costs) of the average wildlife vehicle collision in North America for three common ungulates.

Cost-effectiveness thresholds

For mitigation to be cost-effective there needs to be a break-even point or a dollar value threshold. Huijser et al. (2009) thoroughly detailed these values for deer, elk and moose in North America (Table 1).

The number of deer-, elk-, and moose-vehicle collisions per kilometer per year were compared to the actual cost of different mitigation measures and the realized effectiveness of each technique. For example, if a road section averages 4.4 deer-vehicle collisions per kilometer per year, a combination of wildlife fencing, under- and overpasses, and jump-outs would be economically feasible, because the threshold value of 4.3 is exceeded (Table 2).

The threshold value for less costly mitigation of fencing, jump-outs and wildlife underpass, however, is 3.2 deer-vehicle collisions per kilometer per year.

Because we know the cost of different mitigation measures per year (Table 2) and their effectiveness at reducing WVCs (see Huijser et al. 2007), we can calculate the break-even point for sections of highway with high WVC rates.

Table 2: Threshold values for different mitigation measures used to reduce deer-vehicle collisions by >80%. Adapted from Huijser et al. 2009.

¹ For explanation of discount rate, see Huijser et al. 2009.

² ADS: Animal detection system

These values exclude values not easily monetized, such as the existence value of wildlife or peace of mind for motorists. Considering these values would tip the threshold values lower. Also, these threshold values are specific to the study area for Huijser et al.

Case studies - Putting the dollars to work!

For reducing WVCs, implementing countermeasures for wildlife will be more readily accepted if cost-benefits can be proven.

Table 1 shows the average cost per collision (i.e., human fatalities and injuries, vehicle damage) ranges from $6,617 (deer) to $30,769 (moose). The average cost of building and maintaining a wildlife passage with fencing is $18,123 per year. The abovementioned research showed that a threshold of 3.2 deer-vehicle collisions per km per year was sufficient for installing fencing and one wildlife underpass. The threshold value for collision rates with elk and moose are even less, 1.2 and 0.7 collisions per km per year, respectively.

Because the cost of different mitigation measures per year is known, as is their effectiveness at reducing collisions with wildlife, it is possible to calculate the break-even point for sections of highway with high wildlife-vehicle collision rates. We applied this cost-benefit model to Highway 3 in the Crowsnest Pass of Alberta and British Columbia. Highway 3 has high rates of wildlife-vehicle collisions. Our mitigation assessment using the cost-benefit model found that half of the high collision sites along Highway 3 in the Crowsnest Pass, Alberta were found to have estimated annual costs in excess of the threshold cost.

A similar highway mitigation assessment using the cost-benefit model was completed on the Trans-Canada Highway east of Canmore, Alberta. The cost-benefit model has also been used to guide local mitigation recommendations for three highway segments in Jackson Hole, Wyoming and a highway segment in northern Idaho.

Suggested reading for more information:

Clevenger, A.P., C. Apps, T. Lee, M. Quinn, D. Paton, D. Poulton, R. Ament. 2010. Highway 3: Transportation mitigation for wildlife and connectivity in the Crown of the Continent Ecosystem. Report prepared for Woodcock, Wilburforce and Calgary Foundations. 54pp.

Huijser, M.P, J. W. Duffield, A.P. Clevenger, R.J. Ament & P.T. McGowen. 2009. Cost-benefit analyses of mitigation measures aimed at reducing collisions with large ungulates in North America; a decision support tool. Ecology and Society 14(2): 15. [online] URL: http://www.ecologyandsociety.org/vol14/issue2/art15/.

Huijser, M.P., P. McGowen, J. Fuller, A. Hardy, A. Kociolek, A.P. Clevenger, D. Smith and R. Ament. 2007. Wildlife-vehicle collision reduction study. Report to U.S. Congress. U.S. Department of Transportation, Federal Highway Administration, Washington D.C. http://environment.fhwa.dot.gov/ecosystems/wvc/index.asp

Lee, T., Clevenger, A. and R. Ament. 2012. Highway Wildlife Mitigation Opportunities for the Trans-Canada Highway in the Bow Valley. Final Report. G8 Legacy Fund, Alberta Ecotrust Foundation. 72pp.