Skip to main content

I-405 Improvement Project

Translated pages

Improving the San Diego Freeway

OCTA in cooperation with Caltrans is improving 16 miles of the San Diego Freeway (I-405) between State Route 73 (SR-73) and Interstate 605 (I-605). It also will construct the 405 Express Lanes from SR-73 to I-605. The new express lanes – incorporating the existing carpool lanes and connectors that opened in 2014 – will be two lanes in each direction.

Interstate 405 Improvement Project logo OC Go Local Tax Dollars at Work

Slater Avenue

Anticipated Milestone Dates

Ward Street Mid-2023
Springdale Street Mid-2023
Newland Street Mid-2023
I-405/SR-73 Connector Mid-2023 *

*The I-405/SR-73 Connector construction is anticipated to be complete in mid-2023 however, it will not be open to traffic until the Express Lanes are completed in late 2023.

I-405 Improvement Project Design-Build Completion: Late 2023

Contact the 405 Community Outreach Team

If you have questions, please contact the Outreach Team by calling (888) 400-8994.

Para obtener más información sobre el Proyecto de Ampliación en el I-405, llame al (888) 400-8994.

Để biết thêm thông tin về Dự Án Cải Thiện Xa Lộ I-405, xin vui lòng liên lạc cô Gia Lý theo đường dây tiếng Việt (888) 662-6569.

Project by the Numbers

Once completed, the I-405 Improvement Project will allow Orange County to keep pace with expected job, housing and population growth, while providing safe and reliable multimodal travel throughout the region.
16 Miles of Freeway
Improved for a quicker, more enjoyable driving experience
18+ Bridges
Replaced and improved
11 New Bike Lanes
Added for more cycling routes
11 New Sidewalks
Added for pedestrian accessibility
40,000+ Jobs
Created during the entire life of the project
6 Corridor Cities
Plus the community of Rossmoor collaborating to keep traffic moving during construction


The $2.16 billion OC Go project, Measure M, being constructed in cooperation with Caltrans, will be funded mostly through a combination of local, state and federal funds, with the express lanes portion of the Project paid for by those who choose to pay a toll and use the 405 Express Lanes.

OC go sales tax funds

$1.4 billion

State Funds

$89.8 million

federal TIFIA

$629 million

Federal Funds

$45.6 million

Project Partners


  • OCTA
  • Caltrans
  • FHWA
  • 40 separate utility owners
  • Orange County Flood Control
  • Union Pacific Railroad
  • Army Corps of Engineers
  • U.S. Navy
  • Emergency service providers such as police and fire

  • Costa Mesa
  • Fountain Valley
  • Westminster
  • Huntington Beach
  • Garden Grove
  • Long Beach
  • Los Alamitos
  • Seal Beach
  • Community of Rossmoor