The I-405 corridor is generally recognized as the busiest road in the U.S.
The I-405 Improvement Project widens the I-405 between SR-73 and I-605, improving 16 miles of I-405 between SR-73 in Costa Mesa and I-605 near the Los Angeles County line. The I-405 project’s objective is to reduce commute times for hundreds of thousands of motorists who travel the I-405 daily by adding general purpose and tolled express lanes; reconfiguring 12 interchanges to improve operational efficiency, reduce congestion-related accidents, and provide safety enhancements. Safety enhancements include reducing lane weaving for through traffic, proper shoulder widths, and striping. Pacific Infrastructure I-405 Designers, a design joint venture led by Moffatt & Nichol provided full engineering services for the 16-mile, $1.9 billion highway infrastructure project, including construction support and maintenance of traffic. Moffatt & Nichol is the lead design firm of the design joint venture as well as the designer-of-record for the freeway expansion and operational improvements.