EAST CONTRA COSTA — Caltrans will limit traffic to one way at a time on Highway 4 a few miles east of Discovery Bay from 8 a.m. to 3 p.m. beginning Tuesday through Friday.
The highway will be closed in both directions in that area from 8 p.m. Friday through 4 a.m. Monday.
The state highway agency needs to impose the restrictions so contractors can replace a culvert under the highway about one mile east of the Old River Bridge in San Joaquin County.
During the closure, Caltrans suggests eastbound motorists take a detour along Highway 160 north, Highway 12 east and southbound Interstate 680 to reach Highway 4.
Westbound motorists are advised to take I-5 south, I-205 west and I-680 north to reach Highway 4.
Highway 4 is a heavily used commute route between Contra Costa and San Joaquin counties.