Highway 4 near Discovery Bay expected to reopen at 9 p.m.

State Highway 4 is closed in both directions Thursday evening just east of Discovery Bay due to an overturned big-rig, according to the California Highway Patrol.

The overturned big-rig was reported at about 2:45 p.m. just west of Old River Bridge in unincorporated Contra Costa County. 

The road will remain closed until the truck is removed, CHP officials said. The estimated time of reopening is 9 p.m.