Update as of 9/30/25: Full Closure Scheduled for Westbound State Route 4 (SR-4) between Cummings Skyway and San Pablo Avenue in Contra Costa County

Monday, September 29, 2025, - Thursday October 2, 2025, 7:00 PM to 6 AM each night
Monday-Thursday only

Contra Costa County — Caltrans will perform an overnight full closure of westbound State Route 4 (SR-4) from Cummings Skyway to San Pablo Avenue beginning Monday, September 29, 2025, through Thursday, October 2, 2025. Closures will be in effect Monday through Thursday nights from 7:00 PM to 6:00 AM.

The closure is necessary to allow paving crews to complete work in the Cummings Skyway area. Please note this schedule is tentative and subject to change depending on weather conditions and construction progress.

Closure Details:

Westbound SR-4 between Cummings Skyway and San Pablo Avenue

• Monday, September 29th through Thursday, October 2, 2025, 7:00 PM to 6:00 AM, each night (Monday through Thursday Only) 

Traffic Control: 

Detour Route for Westbound SR-4 

1. Exit Cummings Skyway Offramp.
2. Turn right onto Cummings Skyway Road.
3. Turn left onto the westbound I-80 Onramp.
4. Exit at the San Pablo Avenue Offramp.

**Flaggers will be in place at Cummings Skyway overcrossing to assit drivers through the established reverse one-way traffic control and temporary traffic signal near I-80 at Cummings Skyway Overcrossing. 

Please follow posted signs and detour routes during the closure periods. Eastbound SR-4 traffic is not expected to be affected.

Motorists are advised to expect delays and allow extra time. For 24/7 traffic updates, follow 511.org on Twitter. For real-time traffic, visit Caltrans QuickMap. 

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