Caltrans plans multiple Highway 37 closures to prepare for El Niño

With a record El Niño likely to bring strong winter storms, Highway 37 in Sonoma, Napa and Solano counties will undergo multiple closures for emergency storm preparation, Caltrans announced.

The closures, which will take place over several weeks, will involve a stretch of the highway between Sears Point in Sonoma County and Mare Island in Vallejo. Crews are expediting work, which will require full shutdowns of the route, officials said.

Shutdowns will begin on Wednesday, Oct. 21 and Thursday, Oct. 22, as Caltrans closes the westbound direction of the highway from 7 p.m. to 4 a.m. the following day.

The following weekend, both directions of the highway are scheduled to be closed for 55 hours, from 10 p.m. on Friday, Oct. 23 through 5 a.m. on Monday, Oct. 26.

During the closures, crews will demolish the median and install K-rail to shift both eastbound and westbound traffic to what are currently the westbound lanes. Once the shift is complete, crews will focus on the eastbound lanes to raise portions of the roadway by three feet to address flooding concerns.

Officials are also planning supplemental closures starting Friday, Nov. 13 at 10:00 p.m. to 5:00 a.m. on Sunday, Nov. 15.

Caltrans said motorists should expect delays and increased travel times. The agency is recommending multiple detours around the closure.

For westbound 37, drivers should exit Highway 29 (Sonoma Boulevard) in Vallejo and head north towards Napa. Drivers should continue to westbound Highway 12 (Carneros Highway) and then to southbound Highway 121, rejoining Highway 37 at Sears Point.

Meanwhile, drivers using eastbound 37 will need to detour by taking northbound Highway 121, making a right on the Carneros Highway (Highways 12 and 121), followed by a right on Highway 12 and 29, rejoining Highway 37 in Vallejo.

Officials said the roadwork is dependent on weather conditions.