Octa's transportation blog

Magnolia Street Bridge Opening Marks I-405 Project Milestone

Late last month, the Magnolia Street bridge over the I-405 opened, marking another major milestone for the I-405 Improvement Project, which is now more than halfway finished.

The Magnolia Street bridge is the fifth to open among 18 being built, widened or replaced as part of the project. Because the bridge was reconstructed one half at a time, it allowed Magnolia Street, which straddles Huntington Beach, Fountain Valley and Westminster, to remain open to traffic during construction, minimizing impacts to the community.

“The new bridge not only benefits the residents and businesses near Magnolia Street, it's also an important step toward meeting the project's overall goal of improving the commutes of the thousands of drivers who travel on the 405 each day,” said OCTA Chairman Andrew Do, also the county's First District Supervisor. “I appreciate everyone's continued patience during construction and hope that everyone who drives the 405 takes some time to support our local businesses along Magnolia Street.”

The first half of the Magnolia Street bridge was demolished in late 2018 and opened to traffic in spring 2020, and then work began on the second half. The new bridge is wider, with six traffic lanes instead of four, and sidewalks and bike lanes on both sides of the street. A video commemorating the opening is available here.  

Four other bridges have also been completed. Slater Avenue in Fountain Valley was the first bridge to open in 2019. Last year, Bushard Street in Fountain Valley and McFadden Avenue, which links Huntington Beach and Westminster, were completed. And in April, Talbert Avenue in Fountain Valley opened.

In addition to the bridge construction, substantial work has been completed to improve on-and off-ramps, widen the freeway and replace soundwalls. As a result, overall construction on the project that began in early 2018 is approximately 55 percent complete.

Next month, the Warner Avenue bridge in Fountain Valley is expected to fully close to traffic for reconstruction. Demolition of the overcrossing will require overnight closures of I-405 near the bridge.

For the latest construction schedule, as well as closure and detour information, visit the project's interactive map.

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