Overview - Construction

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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.

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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.

  • 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
  • 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
  • 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

4 miles

Corridor Cities

Irvine, Santa Ana and Tustin

Total Estimated Cost

$475.1 million


August 2022 to 2026

Construction Closures & Detours

Closures and detours for the SR-55 Improvement Project

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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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