In the U.S. state of Washington, a road called ^Interstate 90^ cuts through a wild, mountainous area to reach the city of Seattle. For the area's many kinds of animals, the busy highway greatly limits their movements. Crossing 1-90—as the road is called—is a risky but sometimes necessary act. But soon, animals will have a safer choice for crossing the road. They will be able to go above it.
To help the animals, the state is finishing work on its largest-ever wildlife bridge. The 11-meter-tall, 20-meter-wide structure begins in the forest. It forms two arches above the highway, one for each direction of traffic. Workers are adding fencing and plants to help guide the animals across the bridge. Two-meter-thick walls will help block noise from vehicles below.
The 1-90 Bridge is part of a growing number of wildlife crossings across the United States. Some are fences, some are overland bridges, and some are underpasses. They all aim to keep drivers and animals away from each other. Collisions between animals and drivers are rarely deadly to people. But they are often deadly to wildlife. In Canada's Banff National Park, studies have found that wildlife crossings reduce the area's animal-driver collisions by 80 percent.
Most of the wildlife bridges are in western states. But experts have noted many other areas that have a need for such paths. Jen Watkins, whose organization has helped campaign for animal crossings, says finding for more crossings is "the number-one barrier."
Patty Garvey-Darda of the U.S. Forest Service has worked on the 1-90 crossing from the start of the project. She says the $6- million bridge will one day pay for itself because the highway will not have to be fully or partly closed each time a large animal is struck. She said, "If you shut down Interstate 90, you shut down interstate commerce."
