Researchers found that deer weren’t using them because, based on their vision, the opening on the other end looked too tiny to pass through, Frey explains, adding that it’s important to keep vegetation clear on both sides so animals feel safe from predators that may be lurking around. Many underpasses were too narrow for large game animals to comfortably pass through. Out west, culverts were easy structures to erect as new highways were built, Frey says. In Utah, the majority of its wildlife crossings are culverts, or underpasses. The moment was captured on a trail camera in the Santa Cruz mountains of California in 2020 and the footage continues to go viral in news stories today. Then together the animals trot through the dark culvert, safely avoiding the busy highway above. A coyote jumps playfully out of a tunnel, tail wagging, as if encouraging its pal, a badger flagging behind, to follow. It could be a scene in a children’s book.

While there is no one-size-fits-all solution, there are numerous methods for rerouting wildlife across busy stretches of roadway, including highway underpasses, overpasses, ramps, and dropdown fencing. Other reasons for investing in wildlife crossings is to protect historic migration routes and the genetic diversity of species like mountain lions that have extensive territories often fractured by roads, neighborhoods, and fencing. “Of course, the larger the animal, the greater the chance that that collision is going to be a fatality.” “When we get wildlife onto our highways they get trapped and freaked out and that’s when you see the vehicle collisions,” says Nicki Frey, a wildlife biologist for Utah State University’s Berryman Institute who specializes in human-wildlife interactions. Transportation studies suggest that when safe passageway is available, collisions with wildlife decrease 90%. In Utah alone, a report from the state’s Department of Transportation’s Research & Innovation Division found that between 20, vehicle collisions with animals produced an annual societal cost of over $138 million. And it’s not just because people love animals, it’s a move that makes economic sense. In 2021, legislatures nationwide pledged hundreds of millions of dollars to connect habitat through the strategic placement of wildlife crossings and partnerships with private landowners. States from California to Florida are banking on it.

Animal overpass