Freeway Projects - SR-55 (I-405 to I-5)

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  • SR-55 (I-405 to I-5)

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    Calina North Image
    Calina North

    Community Relations Specialist, Principal

    (888) 371-2555
    Stay Informed

Overview Tab Content:

  • SR 55 header

    Project Overview

    The Costa Mesa Freeway (SR-55) is one of the most heavily congested freeways in Southern California. SR-55 is a vital link to other major freeway systems in Orange County, and it is the only freeway providing a direct north-south connection between Central Orange County and the coastal region. Currently, SR-55 between Interstate 405 (I-405) and Interstate 5 (I-5) has four general purpose lanes, one carpool lane and some auxiliary lanes in each direction. The heavy congestion on SR-55 is expected to increase with future demand. This project will add new lanes to this stretch of the freeway to help with traffic flow and improve traffic operations.

Details Tab Content:

  • About the Project

    The project will add one regular lane and one carpool lane in each direction, as well as auxiliary lanes between several interchanges on SR-55 between the I-405 and I-5. The 4 mile Project also includes:

    • Improving four bridges
    • Constructing retaining walls
    • Reconfiguring on- and off-ramps
    • Reconstructing a lane channel
    • Relocating utilities
    • Modifying and realigning local streets

    Construction began in early August 2022 and is expected to be completed in 2026.


    The total project cost is $475.1 million. The project is funded by OC GO (also known as Measure M, Orange County’s half-cent sales tax for transportation improvements), state and federal funds. The California Transportation Commission awarded OCTA $140 million in competitive state transportation funding to support the project.

    Project Schedule

    SR 55 Anticipated Schedule

    Focus on 55 Business Program

    focus on 55 logo  

    OCTA’s Focus on 55 Program supports eligible local businesses along the SR-55 Improvement Project corridor. We offer marketing assistance to increase exposure and encourage consumers to shop local during construction. Participation is free.

    Benefits to Businesses
    Free participation
    Social media and email marketing

    Benefits to Customers
    Discover deals and special offers
    Support businesses and keep sales tax local

    Participating Businesses

    Official Rules Disclaimer: Businesses are eligible to sign up at There is no cost for businesses to participate. Benefits to local businesses include the following: social media and email marketing, print and digital ads, and coupon promotions. For a business to be eligible, their physical address in the cities of Irvine, Santa Ana or Tustin. The following business types are excluded: liquor stores, adult/sexual content, medical and recreational marijuana, weapons and any other business not approved by OCTA. Participating businesses must submit and/or approve web profile information. Businesses agree to keep the Project updated with contact, images, logos (.jpg, .pdf, .ai or .eps). Participating businesses acknowledge and understand that OCTA may publish and display the company's name, photographs, likeness and biographical information for any purpose, including advertising, promotional and publicity in all forms of media, in perpetuity, without further authorization, approval, notification or compensation of any kind. Featured businesses may request copies of photos, videos, art files and other marketing materials displaying their images with written requests to The program is scheduled to continue through 2026. OCTA reserves the right to change, amend, extend, cancel or discontinue the program at any time, with no advance notice.

Detours Tab Content:

  • Lane and Ramp Closures

    Contractors continue to restripe lanes along northbound (NB) SR-55, shifting traffic toward the center median, as well as placing temporary concrete barriers along the outside shoulders to separate work areas from traffic. Following this work, construction crews are expected to clear vegetation within the work area.

    To facilitate this work, the following nighttime lane and ramp closures are planned from 10 p.m. to 5 a.m.:

    Nightly, Wednesday, Sept. 28 through Friday, Sept. 30:

    • NB SR-55, two outside lanes closed between MacArthur Boulevard and McFadden Avenue

    Wednesday night, Sept. 28:

    • NB SR-55 Dyer Road on-ramps
    • NB SR-55 Edinger Avenue off-ramp

    Thursday night, Sept. 29:

    • NB SR-55 Edinger Avenue on- and off-ramp

    Friday night, Sept. 30:

    • NB SR-55 Edinger Avenue on-ramp
    • NB SR-55 McFadden Avenue off-ramp

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

    Once striping is complete and concrete barriers are placed on NB SR-55, crews are anticipated to begin nightly lane and ramp closures on southbound (SB) SR-55 in early October.

    Detour signs will be posted to direct traffic when on and off-ramps are closed.

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