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     OCTA and OCGO Logo DarkBlue

Ward Street

Contact the 405 Community Outreach Team

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