Closures Rescheduled For July 10-13 and July 17-20, 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, July 10, until 5:00 a.m. on Monday, July 13, and from 10:00 p.m. on Friday, July 17, until 5:00 a.m. on Monday, July 20, 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.
- Local access: Only local residents and business owners will have access to locations within the closure limits.
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 where necessary, along with installing approach and departure slabs, 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.
Motorists should expect 5-to-10-minute delays and use alternate routes whenever possible. All work is scheduled to occur as listed but is subject to change due to traffic incidents, weather, availability of equipment/materials, and construction-related issues.
For the safety of workers and other motorists, please Be Work Zone Alert. Caltrans also reminds motorists to #KnowBeforeYouGo by checking QuickMaps on your mobile device or visit quickmap.dot.ca.gov for real-time highway conditions.
