Animal-activated highway crosswalk: long-term impact on elk-vehicle collisions, vehicle speeds, and motorist braking response

Abstract

After reconstruction of a highway section with three wildlife underpasses, but only limited wildlife exclusion fencing, elk (Cervus canadensis)-vehicle collisions (EVC) increased 21%. We retrofitted an existing 1-m right-of-way fence along 4.2 km, raising it to 2.2−2.4 m in height and tying it into underpasses at the project’s east end. With no logical western fence terminus, we installed an animal-activated detection system (AADS) and motorist alert signage at a designated at-grade crosswalk to prevent collisions when animals crossed. Our goal was to achieve modified motorist behavior without long-term habituation while allowing wildlife to cross via the crosswalk, promoting highway safety and landscape connectivity. Before-project EVC (9.33/year) declined 97% after the new fencing. Our AADS achieved reduced vehicle speeds (13%) and increased motorist alertness (5.5-fold increase) with signs activated. Average speed reduction and braking response remained significantly higher with sign activation across all 9 years of our evaluation. Thus, our place- and time-specific AADS design successfully modified motorist behavior without habituation.