PB&A has performed a myriad of professional design services for our client, Kiewit Infrastructure West, on this massive infrastructure freeway widening project. This 11 mile section of freeway carries 500,000 cars daily over the Sepulveda Pass and into the Los Angeles basin, making it one of the most heavily trafficked freeways in the United States. The project will add a 10 mile HOV lane on Northbound I-405, replace the Skirball, Sunset Blvd. and Mulholland Drive bridges, widen 13 existing underpasses and structures, all which will require the construction of 18 miles of retaining walls.