Highway 4 Closures Planned At Contra Costa, San Joaquin County Line

CONTRA COSTA AND SAN JOAQUIN COUNTIES, CA — Caltrans announced two consecutive nights of eight-hour full highway closures as testing takes place on the state Highway 4/Old River Bridge at the San Joaquin/Contra Costa County line, east of Discovery Bay.

Testing is required as completion nears on the ongoing bridge preventative maintenance and rehabilitation project that involves upgrades and repairs to the 100-year-old bridge.

The first overnight closure starts at 8 p.m. Monday, March 25, and continues until 4 a.m. Tuesday, March 26.

The second closure is from 8 p.m. Tuesday, March 26, until 4 a.m. Wednesday, March 27.

Detour Routes

• For westbound travelers, the detour begins at the Tracy Boulevard intersection; south on Tracy Boulevard; west on I-205; north on Mountain House Parkway; and northwest on Byron Road to SR-4.
• For eastbound travelers, the detour begins at the Byron Road intersection; southeast on Byron Road; south on Mountain House Parkway; east on I-205; and north on Tracy Blvd to SR-4.

Caltrans will use flaggers and portable overhead changeable message signs to alert motorists of the detour and potential delays — expected to take approximately 30 minutes.

1-Way Traffic Control

One-way traffic control is also required at the SR-4 Old River Bridge from 7 a.m. to 3:30 p.m. Friday, March 22; and from 9 p.m. to 4 a.m. Wednesday, March 27, through Friday, March 29.

100-Year-Old Swing Span Bridge

The required project was to upgrade existing mechanical and electrical components and implement structural repairs to increase the reliability and serviceability of the 100-year-old swing span bridge.

Work includes repairing or replacing equipment that operates the movable portion of the bridge; replacing the electrical power supply to the bridge by installing a new cable in the river bottom; and adding a new control board and associated equipment to the control house above the traveled way of SR-4 on the bridge structure.

See more information on the Caltrans webpage: State Route 4 Old River Bridge Maintenance.

Schedules are subject to change because of traffic incidents, weather, equipment/materials availability or other construction-related issues.