The Costa Mesa Freeway (SR-55) is one of the most heavily congested freeways in Southern California, with more than 260,000 vehicles traveling on it every day. By 2040, that volume is expected to grow to more than 275,000 vehicles per day. SR-55 is a vital link to major freeway systems in Orange County, and the only freeway providing a direct north-south connection between Central Orange County and the coastal region. Approximately 1.5 million people reside within five miles of this corridor, which also serves Orange County’s major employment centers, with 950,000 jobs at the South Coast Metro and Irvine Business Complexes.

Southbound traffic on SR-55 at Dyer Road.

To improve access and travel time, the Orange County Transportation Authority (OCTA), in cooperation with Caltrans, is improving four miles of SR-55 between I-405 and I-5. Security Paving is the general contractor performing the work. The $475-million project is funded through a combination of local, state, and federal funds, including $140 million from Senate Bill 1 (SB1), the Road Repair and Accountability Act of 2017.

“The additional HOV lanes will encourage more people to carpool and rideshare, which may be able to reduce vehicle miles traveled and travel times for commuters,” said Caltrans District 12 Director Ryan Chamberlain. “The SR 55 Improvement Project also represents the investments we’ve made through SB 1 to fix our roads, freeways, and bridges.”

The SR-55 Improvement Project will improve traffic flow and reduce travel time by adding one regular lane and one carpool lane in each direction. Currently, there are four regular lanes and one carpool lane in each direction. Work began in August 2022 and is targeted to complete in 2026.

In January, Security Paving crews demolished the concrete barrier along the east side of the SR-55 bridge over MacArthur Boulevard to enable widening of the structure.

The scope of the project includes improving four freeway bridges over MacArthur Boulevard, Dyer Road, Edinger Avenue, and the BNSF/Amtrak Metrolink railroad crossing. In addition, a new sound wall is being constructed near the SR-55/I-5 interchange, along with new retaining walls throughout the corridor. On- and off-ramp reconfiguration is also taking place, with phased construction starting in 2024. According to Security Paving’s Sal Deraki, more than 15,000 cubic yards of Jointed Plain Concrete Pavement is projected to be placed, including 1,000 cubic yards of Rapid Set JPCP.

New merge lanes are being added on northbound SR-55 at MacArthur Boulevard, Dyer Road, and Edinger Avenue to improve traffic flow, reduce travel time, and enable safer merging. New overhead signs and lighting are also being installed, and extensive restriping is taking place.