PORTLAND, Ore. (KOIN) – Wildlife crossings over highways in Washington save people hundreds of millions of dollars every year by helping avoid traffic collisions, a new analysis revealed.
Wisnu Sugiarto, a WSU economics doctoral student, studied data from the Washington State Department of Transportation from 2011 to 2020 and found that each wildlife crossing structure saved roughly $235,000 to $443,000 in crash expenses every year.
The research also revealed there were 1 to 3 fewer collisions involving wildlife per mile each year in a 10-mile radius around each wildlife crossing in the study.
“Wildlife crossing structures not only benefit the ecosystem but may also improve road safety,” Sugiarto said.
His study was published in the Transportation Research Record.
This is the first known study to look at the reduction in wildlife-vehicle collisions in Washington, but similar discoveries were found by studies in North Carolina, Utah and Wyoming.
The structures, which are often either tunnels that allow animals to pass under roads or bridges that allow them to walk over, help animals move in search of food and escape predators and wildfires.
Soon, there could be many more of these animal crossings across the country. The Infrastructure Investment and Jobs Act signed into law in 2021 allotted $350 million to building more crossings. A tunnel-like underpass costs about $500,000 to construct and a broad bridge crossing costs more than $6 million.
For Sugiarto’s study, he analyzed data from 13 bridges and underpasses and compared wildlife-vehicle collisions before and after the structures were built. He also looked at an area elsewhere in the state with no structures for comparison. He only looked at WSDOT data through 2020, since traffic patterns changed immensely during the pandemic.
The research found that there were more consistent, significant reductions in collisions around bridges. Deer are the animals most likely to be involved in the collisions and these crashes tend to cost on average about $9,000 per accident.
Cameras at the crossings show that deer tend to use bridges more often than tunnels. Predators like black bears appear to prefer the underpasses.
The study used official reports of wildlife-vehicle collisions, which are only required when the damage totals $1,000 or more. Sugiarto said future research might look at insurance claims, which would reveal more data and could possibly show greater benefits that result from the structures.
In the time period that was studied, there were more than 1,600 wildlife-vehicle crashes every year in Washington. About 10% of them resulted in injuries to the people in the vehicle and a few people died in the crashes.
“From a driver’s point of view, they may choose to drive safely, but still, unfortunately, there are animals that cross the road, and they end up hitting them. This shows there’s something we can do about these collisions,” Sugiarto said.
Decreasing wildlife-vehicle crashes would reduce unnecessary trauma and could potentially save lives and money, he said.