Overnight Full Closures of State Route 4 (Marsh Creek Road) Between Vasco Road and Byron Highway in Contra Costa County

Scheduled to begin Sunday, May 3, 2026, through Thursday May 21, 2026
Sunday through Thursday, 9:00 PM to 6:00 AM (nightly)

Contra Costa County - Caltrans will soon begin a new paving project on SR-4 between Hillcrest Avenue and Byron Highway in Contra Costa County. To ensure the safety of workers and motorists, Caltrans will implement full closures of SR-4 Marsh Creek Road between Vasco Road and Byron Highway, beginning Sunday May 3, 2026, to Thursday, May 21, 2026, at 9:00 PM to 6:00 AM, nightly Sunday through Thursday. Only local residents and business owners/employees will have access to locations on SR-4 within the closure limits.

*All work is weather dependent and subject to change.

State Route 4 Marsh Creek Road Detour Information:

• Westbound SR-4 travelers: Detour begins at Byron Highway left on Brentwood Blvd, left on Sellers Ave, right on Payne Ave, left on Walnut Blvd, Vasco Rd to SR-4.
• Eastbound SR-4 travelers: The detour begins at Vasco Road; left on Walnut Blvd, right on Payne Ave, left on Sellers Ave, right on Brentwood Blvd, continue on Byron Hwy to SR-4.

Please follow posted signs and detour routes during the closure periods. 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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