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animal bridges

Across the U.S., drivers hit millions of animals each year, according to a 2020 Federal Highway Administration report. Approximately 200 people die, 30,000 more are injured, with an upward cost of $8 billion a year, not to mention the death of the animals involved. These animal ecosystems and local economies are fully intertwined. Introducing green bridges and underpasses to strategic, high wildlife migration corridors has been found to alleviate most of these devastating statistics, and promote a healthier, connected landscape.


Trappers Point in Wyoming, for example, reduced the carnage by over 90% once wildlife crossings, underpasses, escape ramps and fencing were built. From Utah’s Parleys Canyon Overpass (aka Slaughter Row) to Washington’s Snoqualmie Pass; from Arizona’s Oracle Road to New England’s Adirondack to Algonquin (A2A), significant favorable impact is continuing to show that green bridges are a common-sense solution to saving lives both human and animal and preserving our wildlife heritage.

Beth Pratt   




1 Earth Day—In 1969, an 800 square mile oil spill occurred off the coast of Santa Barbara, CA. In response, then President Nixon established the Environmental Protection Agency (EPA), Congress adopted the Clean Water Act (1972), Coastal Zone Management Act (1972), and the Endangered Species Act (1973). Earth Day in Santa Barbara is a celebration of awareness and reverence for the planet held annually on April 22.

2 101 Freeway—roughly follows in CA, the Missionary Road aka El Camino Real, Spain’s earliest efforts to colonize the area circa late 17th century. It established a trail, later a road, which connected the missions within a days’ ride of each other. The 101, as Southern Californians call it, is a major North/South U.S. route stretching over 1500 miles from Los Angeles, CA to Olympia, WA.

3 Los Angeles—approximately 35 miles north-west of downtown LA, on the western, ocean-side of LA County.

4 Longest—Natuurburg Zanderij Crailoo is an overpass that spans more than a ½ mile!!


IF THIS THEN... Interesting Engineering | BBC News | Going Green | Mountain Lions

This past April on Earth Day1, a ceremony was held to break ground on construction of the largest wildlife crossing in the world. This green bridge is being built over the California 101 freeway2 near Los Angeles3, and will restore and connect a divide between the Santa Monica mountains conservancy and Liberty Canyon Preserve. At 210 feet long and 165 feet wide, this bridge will finally allow local and migrating animals to expand their habitat into a
150, 000-acre recreational space after crossing the 10 lane road. Linked habitat gives more options for food, water, and most importantly, biodiversity.


National engineering for incorporating wildlife-friendly transportation policies and crossings was first publicly developed in France in the 1950’s. From there it was mirrored across Europe and eventually various countries around the world. The Netherlands alone has over 600 crossings and is home to the longest4 animal crossing in the world. Wildlife bridges, under-crossings and tunnels may be found in Australia, Belgium, Canada, Germany, Japan, Kenya, and New Zealand to name a few.

We don’t necessarily need a Yosemite on every block, but we do need to connect these parcels of open space. We need these everywhere.

A rendering of the wildlife bridge crossing, which will feature native plants and vegetated walls. AP