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United States

I-5 Widening Design and Construction

Delivering PA/ED and PS&E on Schedule and Within Budget


When the Orange County Transportation Authority (OCTA) took on a $450 million project to widen the I-5 mainline for approximately six miles from SR-73 to El Toro Road, the construction and design teams faced numerous technical challenges. Plans for Segment 2, the largest, central segment of the project, added a general-purpose lane, reestablished existing auxiliary lanes, and constructed retaining walls and sound walls. Strict right-of-way constraints and steep grades at the La Paz Road/Cabot Road intersection required creative geometric solutions to reduce impacts to adjacent businesses and residents.


As part of our leadership of the Project Approval/Environmental Documents (PA/ED) and Plans, Specification, and Estimates (PS&E), TRC provided signing/striping, electrical plans, the Transportation Management Plans and construction staging concepts to support the geometric development at the Avery Parkway and La Paz Road interchanges. To eliminate throwaway cost, our team ensured that new structures were being built in their ultimate location. We also prepared the Mitigated Negative Declaration/Finding of No Significant Impact and Project Report for the entire six-mile corridor. In conjunction with TranSystems, our team also prepared the PS&E for Segment 2 of the project.


Through close involvement with OCTA, Caltrans District 12, and the Federal Highway Administration, the team delivered the project on an expedited schedule to meet OCTA’s M2020 plan commitments. Also, the PA/ED estimate fell within one percent of the modeled estimate due to our efficiency in eliminating certain throwaway costs.

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