Contra Costa County — Caltrans construction has begun a paving project on State Route 4 (SR-4), between Hillcrest Avenue and Byron Highway in Contra Costa County. For the safety of both workers and motoring public, full closures of SR-4 Marsh Creek Road between Vasco Road and Byron Highway will be in effect. Closures begin at 7:30 PM on Sunday, May 3, 2026, and last until 5:00 AM; they will continue nightly through Thursday, May 21, 2026, each Sunday through Thursday between 7:30 PM and 5:00 AM. Access during these times will only be available to local residents as well as business owners and employees needing to reach locations within the closed section of SR-4.
Please note 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 Balfour Rd., right on to westbound SR-4.
- Eastbound SR-4 Travelers: 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 eastbound SR-4.
Please follow posted signs and detour routes during these 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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