Highway 37 closes for 55 hours starting Oct. 23 as crews prepare to raise the eastbound lanes
Caltrans will shut the highway in both directions between Mare Island and Sears Point for a full weekend, after two nights of westbound-only closures, as part of the work to lift the flood-prone eastbound lanes by three feet.
VALLEJO: Caltrans District 4 has announced a 55-hour full closure of State Route 37 in both directions, from the Mare Island interchange in Vallejo to Sears Point at the junction with State Route 121 in Sonoma County, starting at 10 p.m. on Friday, Oct. 23 and ending at 5 a.m. on Monday, Oct. 26. Two westbound-only night closures come first, on Wednesday, Oct. 21 and Thursday, Oct. 22, from 7 p.m. to 4 a.m. each night, according to the Caltrans advisory published on Oct. 13.
During the full closure, crews will demolish the median and install concrete k-rail barriers so that traffic in both directions can be shifted onto the westbound lanes. That shift frees the eastbound side for the next phase of construction, and Caltrans says drivers should expect significant traffic delays and use alternate routes while the work is underway. All of the scheduled work is weather dependent.
Raising a highway that floods
The point of the traffic shift is the eastbound lanes themselves. Caltrans says portions of the eastbound roadway will be raised by three feet to make the highway more resilient to flooding, and it describes the closure weekend as part of its emergency preparedness ahead of El Nino storm conditions, with crews expediting the timeline. Route 37 runs about 21 miles along the north shore of San Pablo Bay between U.S. 101 in Novato and Interstate 80 in Vallejo, and its low-lying stretches have a long record of storm closures. The Metropolitan Transportation Commission's fact sheet for the Sears Point to Mare Island improvement project says the work raises the highway's profile grade to remove low spots and prevent near-term flooding of the corridor.
Detours, and what comes next
Eastbound drivers will detour off the highway onto northbound State Route 121, turn right onto State Route 12 and State Route 121 at Carneros Highway, continue to State Route 12 and State Route 29, and take the connector loop ramp back onto eastbound Route 37, according to Caltrans. Westbound drivers will exit onto northbound State Route 29, follow it to westbound State Route 12 and then southbound State Route 121 back to westbound Route 37. Caltrans says changeable message signs have been deployed to alert drivers to the closures.
The work does not end with the October weekend. Caltrans has also scheduled follow-on overnight closures on the weekend of Nov. 13 to 15, when crews will remove the temporary barrier and shift it to the eastbound side of the highway. The corridor carries roughly 40,000 commuters a day, according to the NorthBay Business Journal, so even the overnight phases are likely to push traffic onto the same Sonoma and Napa county detour routes.
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