Temporal patterns of ungulate-vehicle collisions in a sparsely populated country

Ungulates (mainly Cervidae and wild boar Sus scrofa) are considered among the most problematic wildlife suffering on roads and causing the largest material losses due to high densities of ungulate populations, spatial and temporal movement patterns, and body size of these animals. Roe deer–vehicle collision (RDVC) as the most usual cause of ungulate fatality on roads may be applied as an appropriate model for understanding ungulate-vehicle collision patterns in general. To better understand, manage, and mitigate RDVCs, a detailed knowledge of the temporal behavioral patterns of roe deer is essential. In order to determine the role roe deer behavior plays in RDVCs, we examine time-dependent patterns of RDVCs in Lithuania, a country with a relatively low human population density and less developed transport infrastructure compared with other European countries with relatively high human population density and more intensive road network. Our analysis includes 5556 RDVC records from 2013 to 2016 and examines both short-term and long-term periods to determine the interrelationship between roe deer behavior and vehicle collisions. Our results document the relationship between RDVCs and season of the year with the highest RDVCs peaks occurring in late spring (May, 817, 14.7% of RDVC) and late autumn (November, 626, 11.3%). The daily RDVC frequency is influenced by seasonal changes in sunrise, sunset, and timing of twilight and the impact of these environmental variables on vehicle operator behavior. Our findings are comparable with those reported elsewhere in Europe and suggest that roe deer temporal behavioral patterns influence RDVCs more than transport infrastructure.