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.