Los Angeles is famous for its broad, congested highways full of cars inching bumper to bumper through traffic. These legendary many-lane highways teeming with vehicles are annoying to commuters, but they’re deadly to local wildlife and can end up as roadkill. Highway 101 runs through Los Angeles County, dividing the habitats of the Santa Monica Mountains and the Simi Hills in the Santa Susana range. This has particularly created extra problems for mountain lions—with the population in the Santa Monica Mountains running into dangerous inbreeding that’s bad for the species. Wildlife bridges are a solution. In late May 2024, the final horizontal girders were added to a wildlife bridge over Highway 101, completing an important phase in the construction. The project began in 2022 as a collaboration between private organizations and governmental institutions. It is to be known as the Wallis Annenberg Wildlife Crossing, and construction is anticipated to be completed in late 2025 or early 2026.
But getting the girders laid, and creating the base structure of the bridge, is a critical step. The first girder was laid on April 15, 2024. Crews worked hard each night, closing lanes of the highway to lay over 80 concrete masses weighing from 126 to 140 tons each. Now spanning eight lanes of road, the girders will support continuing work to build a concrete floor and then cover the bridge with native plant life. Wildlife will be funneled over the bridge by fences that channel their migration. Cougars, snakes, coyotes, deer, and even insects will be able to roam freely into previously difficult-to-access regions. The hope is this will prevent the sort of injuries discovered on P-22, the famous mountain lion of Griffith Park. When he was sadly euthanized, examination of his organs and bones indicated he’d likely been hit by a car before. The bridge will also allow the mountain lions to range freely, finding new genetics to mate with and strengthening the species. For updates as the work on the bridge continues, you can follow along with announcements on the bridge’s website.
