Drivers in Southern California should prepare for significant traffic disruptions on the Interstate 405 Freeway, as a $115.2 million construction project is set to begin on July 27, 2026. The California Department of Transportation (Caltrans) announced that the multi-year initiative will result in extensive weekend lane closures and detours, lasting until 2031.
The project will impact a critical stretch of the I-405 from the Orange County line to the I-110 interchange. Caltrans officials stated that the goal is to preserve aging infrastructure, enhance safety, and modernize surrounding streets. Over 118 lane miles of concrete roadway and 96,000 square feet of bridge surfaces will undergo repaving and restoration. Additionally, 800 feet of underground drainage culverts will be replaced.
Improvements will also include the installation of nearly 57,000 feet of upgraded guardrails, 11 crash cushions, and new lighting. The project incorporates advanced technology, with 15 new CCTV cameras, 1.5 miles of fiber-optic cables, 34 ramp meters, 5 traffic-counting census stations, and 3 electronic message signs being installed to manage traffic flow.
Beyond the core infrastructure work, the project encompasses aesthetic and environmental upgrades, including landscaping between Lakewood Boulevard and Long Beach Boulevard. Green-painted bike lanes will be added at ramps, alongside 95 ADA-compliant curb ramps for pedestrians.
Caltrans plans to conduct major construction work over weekends and during off-peak hours to minimize inconvenience, but unavoidable traffic congestion is expected. Residents living near the I-405 corridor may also experience increased noise and dust as a result of the construction activities.
Project schedules are subject to change due to weather or operational issues. Drivers are advised to check current road conditions, active lane closures, and detour information using the Caltrans QuickMap tool, available at quickmap.dot.ca.gov.