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SR-55 (I-405 to I-5) Improvement Project

Construction Updates

OCTA, in cooperation with Caltrans, is improving 4 miles of SR-55 between I-405 and I-5. The project will add one regular lane and one carpool lane in each direction, as well as merge lanes between several interchanges.

Project Details

SR-55 is a vital north-south freeway that links central Orange County and beyond to the coastal region. More than 260,000 vehicles use this stretch of SR-55 every day, and that number is expected to grow to nearly 275,000 vehicles by 2040. To address this demand, OCTA and Caltrans are working together to deliver improvements to SR-55 between I-405 and I-5.

roadway
  • Add one regular lane and one carpool lane in each direction between I-405 and I-5
  • Relocate local streets or narrow the width of some surface streets
structure
  • Improve four freeway bridges over MacArthur Boulevard, Dyer Road, Edinger Avenue and a railroad crossing
  • Build one sound wall near the SR-55/I-5 interchange and construct retaining walls throughout the corridor
  • Reconfigure on- and off-ramps
operational
  • Restripe regular lanes
  • Restripe carpool lanes for continuous access, making it easier for motorists to enter and exit the lanes
  • Add new merge lanes on northbound SR-55 between MacArthur Boulevard and Edinger Avenue
  • Install overhead signs and lighting
details
Length

4 miles

Corridor Cities

Irvine, Santa Ana and Tustin

Total estimated cost

$505.7 million

Schedule

August 2022 to 2027

Kenyon Pointe and El Paseo Communities

To learn more about construction activities happening near the Kenyon Pointe and El Paseo communities, as well as neighborhood meetings and events, click here.

Striping Activities & Concrete Barrier Placement – Northbound SR-55 Nighttime Closures

what

Crews are shifting traffic towards the center median to create a work area along the shoulder. This activity requires temporarily restriping lanes and placing concrete barriers along northbound (NB) SR-55 between Edinger Avenue and the I-5 freeway.

when and where

Construction activities require closures. At least one lane will remain open on NB SR-55 at all times.

9 p.m., Monday, March 30 to 5 a.m., Tuesday, March 31:

  • Four inside lanes on NB SR-55
  • NB SR-55 to NB I-5 HOV Connector

9 p.m., Tuesday, March 31 to 5 a.m., Wednesday, April 1

  • Three outside lanes on NB SR-55 between Edinger Avenue and I-5
  • NB McFadden Avenue On- and Off-Ramps
  • NB SR-55 to NB and SB I-5 Connectors

This work may be loud. The schedule is subject to change due to inclement weather or unforeseen operational issues.

closures
closures

Construction Closures & Detours

Closures and detours for the SR-55 Improvement Project

Construction Accomplishments



Lane Channel

Construction of the 3,139-foot-long Lane Channel was completed in September 2025 after being demolished in Spring 2023.

This milestone required tremendous effort from construction crews and included activities such as installing and removing temporary shoring beams, excavation, backfilling, and concrete pours. Previously a V-shape channel, the new U-shape configuration was designed to withstand a 100-year storm while increasing stormwater capacity.

Lane Channel before demolition and reconstruction
Lane Channel before demolition and reconstruction.
Reconstructed Lane Channel as of Sept. 2025
Reconstructed Lane Channel as of Sept. 2025.

retaining walls

Retaining Walls

A total of 18 retaining walls are being constructed as part of the SR-55 Improvement Project. Six of the 18 walls are currently under construction, and 12 walls have been completed.

Utility Relocation

All utilities, including gas, water, sewer, and communications lines have been relocated. This work began in 2021 and required tremendous effort and coordination between contractors and external utility companies such as Southern California Edison. Remaining utility work includes construction crews installing their own electrical services throughout the corridor.

Utility Relocation

Bridge Construction Timeline

Bridge Construction Timeline

Social Media Feed



Latest Activity

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SR-55 Improvement Project Construction Alert
Week of March 30, 2026
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SR-55 Improvement Project Construction Alert
Week of March 23, 2026

Contact the SR-55 Community Outreach Team

If you have questions or would like to request information in another language, please contact the Outreach Team at (888) 371-2555 or email SR55Info@octa.net.

Text "55FWYProject" to (877) 587-3065 to receive text alerts.

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