Two, 55-Hour Full Highway Closures Of State Route 4 From Roberts Road To San Joaquin/Contra Costa County Line

Closures Scheduled For May 1-4 And May 15-18, 2026, - Detour Required

San Joaquin County - Caltrans will perform two, 55-hour full highway closures of State Route 4 (SR-4) from Roberts Road to the San Joaquin/Contra Costa County line, east of Discovery Bay as required for construction of the SR-4 Delta Pavement Improvement Project. This project will make necessary upgrades and repairs of approximately nine miles of existing highway between the county line and South Whiskey Slough Road in Holt, just west of Stockton.

Weekend closures will occur beginning at 10:00 p.m. on Friday, May 1, until 5:00 a.m. on Monday, May 4, and from 10:00 p.m. on Friday, May 15, until 5:00 a.m. on Monday, May 18, 2026. During these closures, the following detour will be required;

State Route 4 Detour Information:

• Westbound SR-4 travelers: From SR-4, take Roberts Road south, continue west on Howard Road, south to Tracy Boulevard to I-205 west, exit Mountain House Parkway, travel north to Byron Road to SR-4.
• Eastbound SR-4 travelers: From SR-4, take Byron Road south to Mountain House Parkway, south to I-205 East, exit Tracy Blvd, north to Howard Road, east to Roberts Road, north to SR-4.

Caltrans will utilize flaggers, as well as overhead and portable changeable message signs, alerting motorists of the detour and potential delays which are expected to be approximately 30 to 40 minutes.

This $21.6 million project is being performed by Bay Cities Paving & Grinding, Inc. (Concord, CA) and is scheduled for 185 working days, which began on April 6, with completion expected in February 2027.

The purpose of this project is to preserve and extend the life of the existing pavement, while improving ride quality for motorists as the pavement within the project limits is exhibiting major distress, which if left uncorrected would continue to deteriorate.

Work will include the repair of failed areas of pavement (dig outs), followed by cold plane and overlay of the existing pavement. Shoulder backing will be placed in both directions, along with upgrading departure barriers, electrical elements, traffic management systems, lighting systems, and sign panels.

Schedules are subject to change due to traffic incidents, weather, availability of equipment and/or materials and construction related issues.