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A PacTrans student researcher from Washington State University’s School of Economics, Wisnu Sugiarto, recently had some research published in the Transportation Research Record on highway animal crossings. This work intended to quantify whether the addition of these structures had an added financial benefit, beyond the benefit to animal populations and migratory health. The paper found that these crossings appear to reduce wildlife-vehicle collisions in Washington state, saving roughly $235,000 to $443,000 every year per structure. Sugiarto said, “Wildlife crossing structures not only benefit the ecosystem but may also improve road safety.”

The primary goal of wildlife crossings are to assist animal movement in search of food and to escape predators and wildfires, but this is the first known study to look at the reduction in wildlife-vehicle collisions in Washington state. Washington state currently has 22 wildlife bridges and underpasses. These structures range in cost from $500,000 for a tunnel-like underpass to over $6 million for a broad bridge like the one near the Snoqualmie Pass on Interstate 90.

In this work, Sugiarto analyzed collision data from the Washington State Department of Transportation from 2011 to 2020. Adjusting for construction time and closeness of other structures, Sugiarto examined data related to 13 bridges and underpasses, comparing wildlife-vehicle collisions before and after the structures were built.

“We often talk about things that we can and cannot control,” said Sugiarto. “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.”

Congratulations Wisnu!