I-405 Improvement Project

Currently, the San Diego Freeway (I-405) is one of the most congested freeways in Orange County, carrying more than 300,000 vehicle trips in some sections each day. By 2040, traffic volumes on the I-405 are expected to increase significantly. The I-405 Improvement Project will increase freeway capacity, improve traffic and interchange operations, and enhance road safety to meet state and federal standards.

The Orange County Transportation Authority (OCTA) in cooperation with The California Department of Transportation (Caltrans) is widening the San Diego Freeway (I-405) between State Route 73 (SR-73) and Interstate 605 (I-605). The I-405 Improvement Project will improve 16 miles of the I-405 and includes the addition of one regular lane in each direction from Euclid Street to I-605, as well as improvements to freeway entrances, exits and bridges. It will also include the construction of the 405 Express Lanes, which will incorporate the existing carpool lanes and consist of two lanes in each direction from SR-73 to I-605. Solo drivers will pay a toll to use the 405 Express Lanes, but carpoolers will be able to utilize the lanes for free. 

I-405 Improvement Project Map


For More Information...

Visit OCTA’s website at www.octa.net/405improvement for up-to-date information about the project and to sign up to receive updates and alerts. You can also follow the project on Facebook (facebook.com/405Improvement) and on Twitter (@405Improvement).  

If you have specific questions about the I-405 Improvement Project, you can contact OCTA's I-405 Community Relations division directly by phone at (888) 400-8994 or email at 405project@octa.net

I-405 Improvement Project Update - March 2017

The OCTA Board of Directors awarded the I-405 Design-Build contract to OC 405 Partners on November 14, 2016.  The Orange County Transportation Authority (OCTA) in partnership with The California Department of Transportation (Caltrans) will start construction on the I-405 Improvement Project in late 2017. The project will include:
  • One new regular freeway lane in each direction
  • Two 405 Express Lanes in each direction
  • 18 bridge replacements
  • Interchange reconfigurations
  • Merge lane improvements
  • New and replaced soundwalls
  • New bike lanes and sidewalks on local streets/bridges

How Will the I-405 Improvement Project Impact Fountain Valley?

The I-405 Improvement Project will have a direct impact on traffic in Fountain Valley, both on and off the freeway. During construction, all seven bridge overcrossings in Fountain Valley will be taken down and replaced in a phased approach manner to minimize traffic impacts to the greatest degree possible. The affected bridges are on Ward Street, Talbert Avenue, Brookhurst Street, Slater Avenue, Bushard Street, Warner Avenue and Magnolia Street. Onramps and offramps throughout the City will also be improved. This construction will cause detours and traffic delays. Once construction starts, drivers are encouraged to stay informed so they can use alternate routes and to be patient with construction workers and fellow drivers. 

There are no full property acquisitions as part of the project. However, there are some locations along the 16-miles of the project where OCTA will require temporary construction easements or partial acquisitions. If you have questions, please contact Christina Byrne, OCTA's Community Outreach Manager, by calling (714) 560-5717 or emailing 405project@octa.net.

I-405 Improvement Activity in Fountain Valley - What's Happening Now?

July 17-21, 2017 - OCTA's contractors will be conducting pre-construction utility location activities between 8:30 a.m. and 4 p.m. and drill exploration activities between 9 p.m. and 5 a.m., on the NB and SB shoulders, outside lanes, and on- and off-ramps along the I-405 freeway near: 
  • Euclid Street
  • Warner Avenue
  • Talbert Avenue
  • Magnolia Street
  • Brookhurst Street
  • Santa Ana River
  Please be advised that these activities may be loud.
July 5-7, 2017 - OCTA's contractors will be conducting pre-construction surveying and drill exploration activities between 9 p.m. and 5 a.m., on the NB and SB shoulders of the I-405 freeway near the following bridges:
  • Brookhurst Street
  • Talbert Street
  • Warner Avenue
  • Slater Avenue
  • Bushard Street
  • Magnolia Street
Please be advised that these activities may be loud.