In recent years, humans have built wildlife crossings in high-traffic areas to prevent road accidents and give animals access to expanded habitats for mating and resources. A new study shows that in certain circumstances, elk and deer can be wary of using these crossings. The findings suggest that further research on species-specific reactions to crossings could help make them more effective.In recent years, humans have built wildlife crossings in high-traffic areas to prevent road accidents and give animals access to expanded habitats for mating and resources. A new study shows that in certain circumstances, elk and deer can be wary of using these crossings. The findings suggest that further research on species-specific reactions to crossings could help make them more effective.