Octa's transportation blog

Improvements Begin on State Route 55

Construction began on the SR-55 (I-405 to I-5) Improvement Project last week to improve mobility along 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 is the only freeway providing a direct north-south connection between Central Orange County and the coastal region. 

The contractor is restriping lanes and placing temporary concrete barriers to create safe areas for construction crews as they begin the work that will benefit those who live or work along this 4-mile stretch of freeway as well as anyone who travels between central Orange County and the coast.

The project will add one regular lane and one carpool lane in each direction of SR-55 between I-5 near Santa Ana and Tustin and I-405 near Irvine and Costa Mesa. It will also add merge lanes to help drivers more smoothly enter and exit the freeway. The additional HOV lanes will encourage more people to carpool and rideshare, which may reduce vehicle miles traveled and travel time for commuters.

In addition to constructing the new lanes, the project will improve four bridges that span the freeway, construct retaining walls, reconfigure on- and off-ramps, relocate utilities and make improvements to local streets.

The freeway is also an important route for commercial trucking, with an estimated 17,000 daily truck trips. The improvements are designed to save up to 1,500 hours in daily truck travel time, helping to also improve air quality. 

The $475.1 million project is funded through a combination of local, state, and federal funds, including $140 million from Senate Bill 1, the Road Repair and Accountability Act of 2017 and OC Go, also known as Measure M, Orange County’s half-cent sales tax for transportation improvements. The project is expected to be completed in 2026.

For more information or to sign up for construction alerts, visit the project website. To receive closure information via text message, text 55FWYProject to 877-587-3065.