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Patterns of Domestic Animal-Vehicle Collisions on Tribal Lands in Montana

Project #: 4WA196
Start Date: 02/01/2023
End Date: 09/30/2024
Status: Current

Awareness of the risk posed to motorists by animal-vehicle collisions (AVCs) has been growing among transportation planners and health and safety experts in recent years (Sullivan, 2011) but most scientific studies, data collection efforts, and mitigation focus primarily or exclusively on wildlife-vehicle collisions (WVCs). Far less attention has been paid to collisions with large domestic animals like cattle, horses, and sheep, which occur less frequently in most regions but are locally common in some areas (Cramer and McGinty, 2018; Zaloshnja et al., 2003).

A recent analysis for the state of Montana (Creech et al. 2019) revealed that domestic animal-vehicle collisions (DAVCs) occur disproportionately on tribal reservation roads, with more than twice as many DAVCs occurring within reservations as would be expected based on their geographic area or highway mileage. These elevated DAVC rates have important implications for the safety of local residents and motorists. In Montana, DAVCs are three times as likely as WVCs to result in human fatalities, and 1.5 times as likely to result in serious injuries (Tyler Creech, personal communciation); similar results have been reported for Utah, Nevada, and Texas (Burton et al., 2014; Cramer and McGinty, 2018; Wildlife Quality Improvement Team, 2005). DAVCs also impose economic costs on tribal communities, including vehicle and other property damages, livestock losses, and potential legal liability for ranchers.


This research will investigate the differences in domestic-animal vehicle collision (DAVC)-wildlife-vehicle collision (WVC) proportions on tribal roads, identify the road segments with high DAVC and WVC rates for each reservation’s roads, and seek to determine the cause of the patterns. Once road segments with high crash rates are identified, these “hotspot” areas will be visited by a team of experts to review the sites and develop an appropriate mix of highway mitigation strategies to address motorist safety and habitat connectivity.


  • Matthew Bell
    Matthew Bell