Featured photo: illuminated road tunnel by Daniel Jerez / Unsplash. Illustrative only; not Caldecott Tunnel or the scheduled inspection work.

ALAMEDA AND CONTRA COSTA COUNTIES — OCTOBER 18, 2026. Motorists driving through the Caldecott Tunnel on State Route 24 should prepare for three nights of planned bore restrictions late this month. Caltrans District 4 announced October 26–28, 2026 closures to conduct fire-safety inspections and routine maintenance. The agency says at least one tunnel bore in each direction will remain open during the work.

Night-by-night Caldecott Tunnel schedule

Each scheduled closure is planned from 10 p.m. to 4:30 a.m. the following morning:

  • Monday, October 26: Bore 2 will close for eastbound SR‑24 traffic.
  • Tuesday, October 27: Bore 1 will close for eastbound SR‑24 traffic.
  • Wednesday, October 28: Bore 3 will close for westbound SR‑24 traffic.

The date refers to the evening the work begins; each closure window extends into the next morning. Caltrans emphasizes that these are individual bore closures, not a full shutdown of all eastbound or westbound travel through the tunnel.

How will travel be affected?

Drivers may need to merge into fewer available tunnel lanes near the work area. This can affect travel between Oakland, Orinda, Lafayette, Walnut Creek and other East Bay communities, especially for people driving at night or before dawn. Caltrans will post electronic message signs and traffic-control instructions.

Why are there different bores?

The Caldecott Tunnel consists of parallel tubes or bores. Closing one tube allows inspection and maintenance crews to work more safely while traffic is carried through the remaining open lanes in each direction. Conditions can still create queues even when the state does not declare a complete route closure.

What work will happen?

The October 15 notice says crews are performing fire-safety inspections and routine maintenance. Caltrans did not announce a new tunnel opening or a major change to the highway alignment. The closure schedule is focused on maintenance access and public safety.

Before you drive

Leave extra time for late-night travel, watch for merging signs, and slow down approaching work crews. Do not assume the same bore will be closed on successive nights: the direction changes on Wednesday. Heavy traffic or incidents elsewhere on SR‑24 may cause additional delays.

Review the official October 15 Caltrans schedule and check QuickMap or 511 Bay Area for current conditions. As with other roadwork, Caltrans says closures are subject to weather and operational changes.

What changes for East Bay residents?

Drivers will encounter temporary capacity reductions on specific nights, but Caltrans expects at least one tube each way to remain open. People working night shifts or traveling for early flights should check the schedule against their usual direction before departing.

For drivers making additional Bay Area trips, we also cover Richmond–San Rafael Bridge lane restrictions beginning October 19, a separate long-term preservation project.

Primary source: Caltrans District 4, October 15, 2026. Planned closures do not constitute live road-status confirmation.

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