The 10 Most Dangerous Stretches of Highway in Montana: MSWP’s New Report Published

High-Risk Zones for Ungulate-Vehicle Collisions during Montana’s Fall Migration Season


Tyler Creech, PhD

Meredith McClure, PhD

Renee Callahan, JD, MESM



Wildlife-vehicle collisions (WVCs) represent a serious threat to human safety and property and to wildlife populations. More than a million WVCs with large mammals occur each year in the United States, resulting in more than 200 human fatalities and 29,000 injuries1. The total cost of the average deer-vehicle collision has been estimated at more than $6,000, and costs are even higher for other large animals (>$17,000 for elk and >$30,000 for moose)2.

Collisions with wildlife and associated injuries to vehicle occupants have increased in Montana in recent years3 (Fig. 1). Nearly 3,000 wildlife-related crashes were reported to law enforcement in Montana in 2015, of which more than 200 resulted in injuries. The actual number of WVCs is likely significantly higher than this because as many as half of WVCs are never reported4. According to a recent analysis by State Farm insurance company, Montana now ranks second highest among U.S. states for risk of vehicle collision with a large animal. Montana drivers have a 1 in 58 chance of hitting a deer, elk, or moose in 2016, representing a 9.1% increase over last year5.

Fall is a period of increased risk of collision with large ungulates (such as deer, elk, and moose), which account for the majority of large animals hit by vehicles1,6. Many ungulates migrate seasonally between higher-elevation summer range and lower-elevation winter range, crossing highways in the process and increasing risk of WVCs. Even in areas without large elevational gradients (e.g., plains habitat in eastern Montana), ungulates often exhibit increased movement across the landscape during fall as males search for and tend to females during the breeding season7,8,9. Hunting seasons for many ungulate species also occur during fall and may further increase movement rates and WVC risk10. Increased driver awareness of specific highrisk areas for fall WVCs could help to reduce these collisions and their associated costs to humans and wildlife, but information on the spatial distribution of WVC risk across Montana is not widely available to the public.

This report identifies short sections of highway that present the highest risk of collisions between vehicles and large ungulates during fall (hereafter, “high-risk zones”). We utilize data on the frequency of wildlife carcasses recorded along highways by the Montana Department of Transportation (MDT) as an indicator of the relative risk of WVCs across Montana (although we note the limitations of this dataset; see Discussion section). We aim to increase driver awareness of highway sections with particularly high risk of WVCs as we enter the fall migration season.

Read the whole report here:

CLLC fall WVC high-risk zones report