I-605/Katella Avenue Interchange
Construction Updates
OCTA, in cooperation with Caltrans, is improving the local interchange at Interstate 605 and Katella Avenue to improve mobility, smooth traffic flow, and enhance pedestrian and bicycle facilities.
Project Details
The I-605/Katella Avenue interchange connects the San Gabriel River Freeway, a major north-south transportation route in Orange and Los Angeles counties, with Katella Avenue, an east-west regional corridor.
The project will improve overall operations for vehicles, bicyclists and pedestrians by:
- Modifying northbound and southbound ramps at Katella Avenue
- Closing the gaps in existing bike lanes by adding Class II bike lanes along eastbound and westbound Katella Avenue
- Enhancing sidewalk connectivity between Coyote Creek Channel and Epson Way
- Constructing Americans with Disabilities Act (ADA) curb ramps and installing new signage and crosswalk pavement markings
Los Alamitos
$32 million
Late June 2025 to Late 2026
Construction Activities
Construction is underway and generally occurs Monday through Friday, from 6 a.m. to 4 p.m.
Center Median Reconstruction
Earlier this month, crews began night work and recently completed the installation of temporary concrete barriers, sawcutting, and lane restriping. Nighttime activities are ongoing as crews reconstruct the new center median on Katella Avenue/Willow Street. Work hours are from 9 p.m. to 5 a.m.
The median work requires the following closures from 9 p.m. to 5 a.m., Monday, July 21to Friday, July 25 (into Saturday morning). View detour map here.
- Inside lane on eastbound and westbound Katella Avenue/Willow Street
- Northbound I-605 on-ramp
Sidewalk Demolition and Reconstruction
Sidewalk reconstruction for new bike lanes is expected to begin in August, which will require pedestrian detours and lane reductions on Katella Avenue.
- Once the schedule is confirmed, additional information will be posted here.
This work may be loud. The schedule is subject to change due to inclement weather or unforeseen operational issues.
Intermittent On- and Off- Ramp Closures
The following ramps are expected to be intermittingly closed this month from 9 p.m. to 5 a.m. nightly. Certain ramps may reopen earlier as crews complete work in certain areas.
Closure: Northbound I-605 Off-Ramp to Eastbound Katella Avenue

Closure: Northbound I-605 Loop Off-Ramp to Westbound Katella Avenue

Closure: Southbound I-605 Loop Off-Ramp to Eastbound Katella Avenue

Closure: Southbound I-605 Loop On-Ramp from Eastbound Katella Avenue

Rendering of Improvements along Katella Avenue

The rendering above highlights planned improvements along Katella Avenue between Coyote Creek Channel and Epson Way. Key features include:
- Reconfiguration of the northbound on- and off-ramps into a T-intersection
- Addition of Class II bike lanes with hatched markings to indicate bike lane transitions
- Installation of a new traffic signal at the northbound I-605/Katella Avenue off-ramp, along with upgraded signals at nearby intersections
- Painted crosswalks and newly constructed sidewalks to enhance pedestrian access and safety
Community Outreach
As part of its comprehensive public awareness campaign, the Public Outreach team is offering opportunities for the community to learn more about the project, its benefits, construction activities, and potential impacts. These include:
- Public webinars
- Neighborhood meetings
- Project briefings and presentations
- Project booths at community events
Construction Closures & Detours
Social Media Feed
Latest Activity
Contact the Outreach Team
If you have questions or would like to request information in another language, please contact the Outreach Team at 888-200-3302 or email 605KatellaInfo@octa.net.
Text "605Katella" to 888-720-7016 to receive text alerts.