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California

Caltrans Began Overnight Caldecott Tunnel Closures

The state has launched a $267 million rehabilitation project for the tunnel bores on State Route 24.

Updated on Oct. 4, 2026 in Home Renovation

Isometric editorial illustration of curved tunnel vaulting and structural steel supports, representing large-scale public infrastructure maintenance.
Caltrans has launched a $267 million multi-year rehabilitation project for the Caldecott Tunnel to address critical structural and ventilation safety concerns. AI Illustration. Upload story photo >

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Do you support the planned overnight tunnel closures for these long-term structural and safety upgrades?

Caltrans has started a massive $267 million structural and ventilation upgrade for the Caldecott Tunnel. The work, which involves bores 1, 2, and 3, is scheduled to last through fall 2029.

Why it matters

Inspections revealed critical deficiencies, and an independent risk analysis ranked these three bores as the highest safety priority in California. The upgrades aim to address long-standing structural and fire suppression vulnerabilities.

The $267 million project covers repairs to concrete, rust, and water damage, while also installing new jet fans and sprinkler systems. Daily closures are restricted to the 10 PM to 4:30 AM window to maintain traffic flow.

The players

Caltrans

This is the California Department of Transportation, the agency responsible for the design, construction, and maintenance of the state's highway system.

Gavin Newsom

He is the Governor of California who announced the funding for the tunnel rehabilitation project in late August 2026.

The details

Construction crews are working to stabilize the interior of the tunnel walls and ceilings to mitigate water damage and corrosion. The project ensures that at least one bore in each direction remains open to traffic during the overnight repair sessions.

Timeline

  1. October 5, 2026: EB Bore #2 closures began.

  2. October 6, 2026: EB Bore #1 closures began.

  3. October 7, 2026: WB Bore #3 closures began.

  4. October 12, 2026: EB Bore #2 closures occur.

  5. October 13, 2026: EB Bore #1 closures occur.

Roadmap

This rehabilitation effort follows the California Structure Maintenance and Investigation division safety protocols to modernize aging state infrastructure. The project marks a significant shift toward prioritizing fire suppression and structural integrity in high-traffic, multi-bore highway tunnels.

Drivers using State Route 24 between Orinda and Oakland should plan for overnight delays as bore closures occur between 10 PM and 4:30 AM. Local commuters can minimize travel disruption by staying informed on which specific bore is scheduled for nightly maintenance.

The takeaway

Large-scale infrastructure maintenance is essential to preserving the longevity and safety of critical state thoroughfares. Residents are encouraged to monitor official Caltrans channels to navigate shifting traffic patterns during the multi-year construction window.

What happens next

The rehabilitation project is scheduled to continue through fall 2029.

Further reading

For more information on infrastructure projects, visit the Home Renovation section.

More information

To receive project alerts, visit the Caldecott Tunnel updates sign up.

Source note: This article includes information reported by Contra Costa Herald | News Of By and For The People of Contra Costa County, California.

Live Poll

Do you support the planned overnight tunnel closures for these long-term structural and safety upgrades?