Reducing Deaths for Wildlife and People on Wyoming Highways
It turns out something as simple as covering roadside reflectors at the sides of highways can deter deer from crossing. But, it’s not what scientists were expecting. During an experiment to test the effectiveness of roadside reflectors, the signs were covered with white canvas bags to keep deer from seeing them. Turns out, the bags were more visible than the reflectors and did a better job of decreasing collisions.
You may have seen the big, rectangular Swarovski crystal reflectors line a number of Wyoming highways. They are arrayed in a way that reflects headlights into a zigzag pattern that designers hoped would deter mule deer from crossing. But, scientists, including TNC’s Corinna Riginos, discovered that the white canvas covers were 33% more effective than reflectors in reducing the number of animals hit. The bags were also more effective in modifying deer behavior, so they were less likely to run in front of a car as the car approached.
A Serious Problem
Every year, an estimated 6,000 vehicles collide with deer on Wyoming roads, and that number may be low. Such collisions can be costly and sometimes fatal to people in the vehicles and almost always result in the death of the deer. Perhaps even more importantly, they indicate places where roads present a barrier to deer movements and migrations, impairing animals’ ability to reach the habitat they need to survive.
A few facts:
- There are 1-2 million vehicle-wildlife collisions a year in the U.S.
- In Wyoming, 85% of the collisions involve mule deer.
- In Wyoming,
totalyearly costs of wildlife collisions are $24-29 million in injury and damage and $20-23 million in wildlife costs.
- The state of Wyoming estimates that, on average, $11,600 in injury and property damage and $4,000 for wildlife costs are incurred per reported collision. Many go unreported.
The canvas-covered reflectors are one way to reduce these accidents, but decreasing the dangers of collisions might require different practices for the different situations.
For example, TNC scientists are currently testing whether temporarily reducing the speed limits on key stretches of road during critical migration periods might help reduce the number of collisions. In other cases, the best solution is to provide safe crossing points with over- or
The good news is that our work has gotten the attention of transportation planners who are now incorporating the findings into their collision-reduction efforts.