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OC Go local tax dollars at work

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

OCTA, in cooperation with Caltrans, is improving 4 miles of SR-55 between I-405 and I-5. The project will improve traffic flow and reduce travel time by adding one regular lane and one carpool lane in each direction. Also, the project will add merge lanes between several interchanges and stripe carpool lanes for continuous access, augmenting safety on the freeway by making merging easier. These enhancements are expected to create a better, smoother driving experience for motorists.

OC Go local tax dollars at work

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 I-405 and I-5 has four regular lanes and one carpool lane in each direction, as well as merge lanes between some interchanges. The project will add another regular lane and a carpool lane in each direction, as well as additional merge lanes on northbound SR-55 between interchanges at MacArthur Boulevard, Dyer Road and Edinger Avenue. This will improve traffic flow and reduce travel time on SR-55, and augment safety by making merging easier.

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


$52.7 million

State Funds

$261.9 million

Federal Funds

$160.5 million

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.

Project Partners

oc go
Federal Highway Administration

Federal Highway

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