It has since reopened but will be closed for the next several weekends.
Highway 29 through Napa can be congested on many days but this weekend was especially tough because cars are being detoured away from Highway 37.
RELATED: What to know about Highway 37 planned weekend closures from Vallejo to Sears Point
Caltrans is repaving the westbound lanes of Highway 37, the 55-hour closure which started Friday night, stretches seven miles from Solano County to Sonoma County.
"We're doing almost 5,000 tons of new asphalt for this weekend and over 300 trucks are needed," said Hector Chinchilla from Caltrans.
Caltrans says the project will continue over the next four weekends, to repave both west and eastbound lanes and detours are posted.
"So we ask motorists, travelers and the public to plan ahead," Chinchilla said.
But drivers like Mary McQuinn from Placerville say they didn't know about the closure.
"We're trying to see a baseball game at 2 p.m. but they're repaving this weekend. They sure picked the right time to do it," said McQuinn.
"It's been awful," said Lexy Griggs.
Griggs and her friends from Sacramento were trying to get to Petaluma.
"It's been a long journey, our ETA went from 1 p.m. to 1:30 p.m. to 2 pm., it's not been fun at all," Griggs said.
The CHP posted on X, the social platform formerly known as Twitter, telling Marin-bound drivers to use the Richmond-San Rafael Bridge but even that span was backed up by Saturday afternoon.
Viansa Winery in the Sonoma Valley posted alerts on its website letting visitors know about the highway closures and detours.
TRAFFIC MAP: Real-time traffic conditions around the Bay Area
Caltrans urges drivers to be patient.
"If you're a local, you understand - if you've driven Highway 37 you know the work was needed and due," Chinchilla said.
Many drivers have complained about too many potholes on Highway 37.
Caltrans says the construction project will continue through the weekend of May 11.