Starting Friday night, Caltrans will shut every westbound lane of the Carquinez Bridge for 53 hours and squeeze Highway 101 through San Francisco down to two lanes each way — two of the region's busiest arteries choked at once. The bigger disruption isn't this weekend, though: it's the full 101 closures Caltrans has already scheduled for Labor Day and mid-September.

The simultaneous closures are routine pavement work, not an emergency — but they land on opposite ends of the Bay on the same weekend, and the San Francisco half is only the opening act of a Hospital Curve rehabilitation that will fully close northbound 101 twice more in the coming weeks. Drivers who shrug off the lane reductions now will meet a full northbound shutdown of the same Cesar Chavez–17th stretch over Labor Day weekend (Sept 4-7).

Two Caltrans projects on opposite shores of the Bay converge this weekend, and the agency is telling drivers to stay off both.

The louder closure is in Solano County. All westbound lanes of the I-80 Carquinez Bridge — the Alfred Zampa Memorial suspension span linking Crockett and Vallejo — shut down at 10 p.m. Friday and stay closed until 3 a.m. Monday↗ (external source, opens in a new tab), a 53-hour outage while crews repave the entire westbound deck. Eastbound traffic is unaffected, and the pedestrian and bike path is closed for the weekend. Caltrans is routing westbound drivers onto I-680 across the Benicia-Martinez Bridge, then State Route 4, to rejoin I-80.

The work is preventative, not structural. "The asphalt that's on it right now is good for 20 years, and we're reaching that age," Sabrina Martinez, Caltrans' public information officer for Solano County, told KQED↗ (external source, opens in a new tab), which reported the roughly $1.4 million rehabilitation. Martinez has said the aim is to deter drivers from the span entirely and steer them to the posted detours. For anyone who would rather skip the drive, San Francisco Bay Ferry is adding five extra weekend sailings between Vallejo and San Francisco.

Across the Bay, Caltrans is narrowing one of the city's most-traveled stretches. Beginning at 11 p.m. Friday and running until 6 a.m. Monday, two northbound and two southbound lanes of U.S. 101's Bayshore Freeway — the Hospital Curve, between Cesar Chavez and 17th streets — will close for median work↗ (external source, opens in a new tab). Two lanes stay open in each direction throughout, per the agency's advisory. Caltrans recommends I-280 as the alternate and, bluntly, that drivers "seriously consider" transit instead. The job is part of what Caltrans calls the Fab 4 Hospital Curve Rehabilitation, a project that began in the fall of 2025.

Here's the part that didn't make the weekend traffic maps: this lane reduction is the gentle version. Caltrans' own advisory lists two full northbound closures of the same Hospital Curve segment still to come — September 4-7, over Labor Day weekend, and again September 18-21↗ (external source, opens in a new tab). During those windows the freeway between Cesar Chavez and 17th closes entirely to northbound traffic, not merely trims lanes. The San Francisco Chronicle flagged the same escalating schedule↗ (external source, opens in a new tab).

For Bay Area drivers, the takeaway is less about this weekend than the pattern behind it. The region's freeways are hitting the far end of their design life all at once — the Zampa deck at 20 years, the Bay Bridge and Golden Gate approaches into their own multi-year rehab cycles — and Caltrans is buying that time back in weekend and holiday closures. This Saturday you lose a couple of lanes. Over Labor Day weekend (Sept 4-7), the full northbound Cesar Chavez–17th closure at Hospital Curve takes the whole road — on the northbound climb out of the Mission toward downtown, you lose it entirely.