I-5 Gateway Reconstruction

TRC retained to provide key oversight role for section of long-awaited, $335 million project delivered in unique public-private partnership effort.


Orange County Transportation Authority

Project Location

Orange County, California

Prior to the project, the 2-mile section of I-5 from the Artesia Freeway (SR-91) to the Orange/Los Angeles County Line was a heavily-traveled segment of I-5 that contained a classic bottleneck in a six-lane facility with only general purpose lanes. The much needed capacity and operational improvements were fulfilled with the completion of a 12-lane freeway facility which includes an HOV lane, four mixed-use lanes and an auxiliary lane in each direction. The HOV lanes on I-5 were extended to the Los Angeles County line, completing the last remaining link of the HOV network for this reach of I-5 in Orange County.

One of the project goals was to deliver the design in partnership with the California Department of Transportation (Caltrans). This goal was fulfilled by separating the two-mile project into two segments; with TRC leading the southern segment and Caltrans leading the northern segment. This unique public-private partnership between Caltrans, the Orange County Transportation Authority (OCTA) and consulting firms not only resulted in a successful delivery, but also strengthened the ties between the two agencies. The partnership also encompassed many other entities, including the Cities of Buena Park and La Mirada, Union Pacific Railroad, numerous utility companies, and adjacent businesses. This partnership was forged early on with the assistance of the consulting firms and maintained throughout construction with OCTA’s extensive public awareness campaign.

The I-5 Gateway Project had many complicated needs to be fulfilled, which namely involved maintaining freeway operation, minimizing impacts to the adjacent railroad tracks and businesses, and mitigating the higher than normal levels of groundwater. Maintaining freeway operation for this segment of I-5 that serves commuters, tourists, and trucking operations was crucial, and was met by employing an extensive stage construction design. Impacts to the Union Pacific Railroad tracks and multiple auto dealerships located adjacent to the freeway were also minimized by utilizing retaining walls to sustain on-going business and railroad operations. The high levels of groundwater impacting the project area were mitigated by placing a waterproof membrane layer within a one-mile section of the roadway and along the backside of the retaining walls to stop the infiltration of groundwater.

TRC was responsible for project management, design oversight, design of the stage construction and traffic handling for this project, and management of the construction support effort. Construction began in May 2006 and was successfully completed in October 2010.

See related services

Highway/Roadway Studies and Design

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