State Route 37 will be fully closed in both directions between Mare Island in Vallejo and Sears Point in Sonoma County from 10 p.m. Friday, Oct. 23, until 5 a.m. Monday, Oct. 26, Caltrans District 4 says. Caltrans warns drivers to expect significant delays and says all of the work is weather dependent.
When is Highway 37 closed?
- Thursday night, Oct. 22: westbound SR-37 closed 7 p.m. to 4 a.m. Friday.
- Friday, Oct. 23, 10 p.m. to Monday, Oct. 26, 5 a.m.: both eastbound and westbound closed between Mare Island and Sears Point (the 55-hour closure).
Caltrans cancelled the westbound overnight closure that had been planned for Wednesday night, Oct. 21, because of possible weather, according to its Oct. 21 update. Its notice also lists westbound closures nightly from 7 p.m. to 4 a.m. on Thursday and Friday.
Eastbound detour
Caltrans says eastbound drivers should exit left onto northbound SR-121 in Sonoma, turn right on SR-12/SR-121 (Carneros Highway), turn right on SR-12/SR-29, then take the connector loop back to eastbound SR-37.
Westbound detour
Westbound drivers should exit right onto northbound SR-29 in Napa, follow SR-29 to westbound SR-12, then take southbound SR-121.
Why is Caltrans closing Highway 37?
Caltrans calls the work emergency preparedness for El Niño storms. Crews will demolish the median and install k-rail so that both directions of traffic can be shifted onto the westbound lanes. Crews will then raise portions of the eastbound roadway by 3 feet to address flooding along the corridor.
Because the schedule depends on weather, check Caltrans QuickMap (quickmap.dot.ca.gov) or 511.org before you drive. Caltrans also lists 1-800-427-7623 for statewide highway conditions.