101 Freeway shutdown will allow major work on a ‘wildlife crossing’ bridge

'Cougar closures' on the 101 Freeway at Agoura Hills will cause delays but bring hope for critters

All lanes of the 101 Freeway in Agoura Hills will be closed overnight starting in mid-April and continuing for six to eight weeks to allow crews to complete a key stage in the construction of the $92 million Wallis Annenberg Wildlife Crossing. The crossing will provide a link for mountain lions and other wildlife to cross into other wild areas that are currently blocked by the freeway.

The overnight closures of all southbound lanes of the 101 between Chesebro Road and Liberty Canyon Road in Agoura Hills will start at 11:59 p.m. Monday, April 15 and continue until Tuesday, April 16 at 5 a.m. Caltrans plans on closing the southbound lanes overnight Mondays through Fridays for several weeks. On Saturdays, they will reopen a little later.

The overnight closure of the southbound lanes will continue for several weeks to allow workers to begin building a crane on site. Once work is completed in the southbound operations, Caltrans will then close the northbound lanes overnight in the same section to allow for large girders to be put in place to form the skeleton of the wildlife crossing.

Caltrans said the overnight closures allow crews to place 82 large concrete girders above the freeway lanes. Each girder weighs between 126 tons and 140 tons. They will reach from the center median to the shoulder of the freeway.

Overnight freeway closures will last between six and eight weeks, said Eric Menjivar, Caltrans spokesperson. But those timelines could be extended depending on circumstances.

All lanes will be closed in only one direction each night and lanes in the opposite direction will stay open for traffic, Caltrans said.

Caltrans will provide a detour on local streets during the overnight closures.

Motorists can bypass the work zone by staying on an all-freeway detour using State Routes 23 and 118 and Interstate 405.

To learn more about the freeway closures, the public is invited to attend an in-person community meeting on Thursday, April 11, from 6:30 p.m. to 8:30 p.m. in the Community Room at Agoura Hills City Hall, 30001 Ladyface Court, Agoura Hills.

The meeting will include representatives from Caltrans, city of Agoura Hills and the National Wildlife Federation, a leading supporter of the project.

The 175-foot wide wildlife crossing will connect two mountain lion roaming grounds, the Santa Monica Mountains and the Sierra Madre Range. In essence, it removes the wide freeway as a barrier, allowing mountain lions as well as bobcats, deer, coyotes even birds and butterflies to safely cross, going from the Santa Monica range into the Simi Hills and Santa Susana Mountains to the north of the 101 Freeway.

Freeway crossings have resulted in more than 35 mountain lion deaths. The most famous cougar, P-22, miraculously crossed the 101 and 405 Freeways and made Griffith Park his home for 10 years until his death in December 2022, ironically from a vehicle-strike.

The mountain lions, or cougars, are hemmed in by the 101, 5 and 405 freeways. These big cats are trapped, forced to procreate with cousins in a limited gene pool that produces diseased offspring. Scientists estimate that without a larger range in which to mate, the unique Los Angeles urban lions could be extinct in 15 years.

Construction of the wildlife crossing began in 2022. Construction was delayed last year and this year due to spring rains, said Beth Pratt, California regional executive director for the National Wildlife Federation and founder of The Wildlife Crossing Fund, in an emailed response on April 8.

“The two record wet springs in a row have now pushed the completion date from the original projection of the end of 2025 into 2026,” Pratt wrote.

She asked commuters and residents to be patient during the overnight freeway closures.

“We are calling these ‘closures for cougars,’ ” Pratt wrote. “We know that closures of the freeway do have impacts on traffic and the community, and we apologize for any inconvenience this may cause, but know people understand these closures are for a good cause — helping to save the area mountain lions from extinction and ensuring a future for all wildlife in the Santa Monica Mountains.”

The public can sign up for free weekly email updates about the wildlife crossing’s construction and closures by sending an email to michael.comeaux@dot.ca.gov or D7inquiries@dot.ca.gov or calling (213) 897-9372.

Travelers may check current highway closures anytime by using Caltrans’ QuickMap service at Quickmap.dot.ca.gov or using the free app for digital devices.

More information is available at the Caltrans web site and at 101wildlifecrossing.org.