The 405 Project: Behind the Scenes

The largest project in OCTA’s history, the I-405 Improvement Project will improve 16 miles of I-405 and add one regular lane in each direction from Euclid Street to I-605. It will also construct the 405 Express Lanes from SR-73 to I-605. This is the third in a series that reports on what’s happening behind the scenes.

To prepare for this extensive design-build project, several task forces meet weekly to discuss all of the project components included in a freeway construction project. Task force members include OCTA, OC 405 Partners (a joint venture of OHL USA, Inc., Astaldi Construction Corporation, and subcontractors), Parsons Corporation (project management consultants), and Jacobs Engineering Group (construction management consultants). Other sub-consultant teams also participate as subject matter experts in various fields including roadway design, structures, and utilities.

One particularly important topic is the development and implementation of a Traffic Management Plan (TMP), which details how road users - including drivers, cyclists and pedestrians - will be directed around construction.

Because TMPs are most effective when customized by location, OCTA is meeting individually with each of the five cities along the construction route to gather feedback and discuss specific local activities and procedures. This close coordination will be ongoing throughout the life of the project.

During construction, closure and detour information will be provided to WAZE and other navigational apps, such as Google Maps, to help drivers navigate safely and efficiently. In addition, stakeholders will be able to opt-in to receive texts and automated calls to assist with daily route planning.

As part of its continuing effort to interact with stakeholders, OCTA is employing a branded 405 Project van that functions like a mobile billboard. The van raises visibility about the project on the road and at events.

For more information and project updates, visit here or contact Christina Byrne, Capital Projects Outreach Manager, at

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