In Los Angeles, even a small freeway closure can turn a quick trip into a lengthy commute. Drivers who regularly use Interstate 405 should prepare for more delays, as Caltrans is beginning a major construction project that will bring years of roadway improvements (and periodic lane reductions) to one of the region’s busiest corridors.
Construction begins Monday, July 27, 2026, along I-405 between the Orange County/Los Angeles County line and the I-405/I-110 interchange. And the project is expected to continue through 2031.
What improvements are coming to the 405?
The $115.2 million project will rehabilitate aging infrastructure while improving safety and accessibility along the freeway.
Some of the biggest upgrades include:
- Rehabilitating 118 lane miles of concrete pavement.
- Repairing more than 96,000 square feet of bridges.
- Replacing more than 800 feet of culverts.
- Installing 11 new crash cushions.
- Upgrading nearly 57,000 feet of guardrail.
- Rehabilitating 38 overhead sign structures.
- Replacing 465 freeway sign panels.
- Installing 15 traffic cameras (CCTV).
- Upgrading 1.5 miles of fiber optic communications.
- Modernizing 34 ramp meters.
- Improving 95 ADA curb ramps.
- Installing three new changeable message signs.
- Upgrading landscaping and irrigation between Lakewood Boulevard and Long Beach Boulevard.
According to Caltrans, the improvements are designed to extend the life of the freeway, improve visibility with upgraded lighting and signage, reduce crash severity with modern safety features, and make nearby pedestrian infrastructure more accessible.
What kind of traffic impacts should drivers expect?
Caltrans says drivers should prepare for extended weekend lane reductions throughout construction. Additional lane closures may also occur as different phases of the project get underway.
Construction schedules may change because of weather or operational needs. Nearby residents and businesses may also experience temporary noise, dust, and vibrations during active work.
If you’re traveling through this section of the 405, it’s a good idea to allow extra travel time, especially on weekends.
How to check traffic before you go
Before heading out, drivers should check Caltrans QuickMap at Quickmap.dot.ca.gov, for real-time lane closures, traffic conditions, and construction updates. Motorists are also reminded to slow down and use extra caution when driving through active work zones.
