SAN FRANCISCO — One of the main freeway approaches into San Francisco is going to disappear for most of Labor Day weekend.
Caltrans plans to close all northbound lanes of U.S. Highway 101 through Hospital Curve beginning at 11 p.m. Friday, Sept. 4, with reopening scheduled by 6 a.m. Monday, Sept. 7. Southbound Highway 101 will remain open. Caltrans closure notice.
A driver heading into San Francisco from SFO, the Peninsula or South Bay should not assume the normal 101 route into the Mission, downtown or the Bay Bridge will be available. Caltrans is urging motorists to use Interstate 280 instead.
Where exactly will Highway 101 be closed?
Caltrans’ official notices use slightly different downstream descriptions. Its Aug. 19 closure notice describes the northbound closure between Cesar Chavez Street and 10th Street, while a later project update references Cesar Chavez to 17th Street. The practical instruction is the same: do not plan to continue north on 101 through Hospital Curve.
Drivers should follow the temporary signs in place when the closure begins. SF News Today is describing this as a closure entering central San Francisco rather than suggesting that every portion of Highway 101 in the city is shutting down.
Coming from SFO or the Peninsula? I-280 is the important road
For people driving north from San Francisco International Airport, the Peninsula or South Bay, Caltrans recommends I-280 northbound for travel toward downtown San Francisco and the Bay Bridge. Drivers beginning near SFO can use I-380 to reach I-280 rather than remaining on northbound 101 until the closure.
The useful move is to make that decision early. By the time traffic reaches the closed section, thousands of other motorists may be making the same detour.
Is southbound 101 closed too?
No. Caltrans says all southbound lanes are expected to remain open during the Sept. 4–7 work. Congestion around the work zone and detour streets could still affect trips in both directions.
Why is Caltrans closing the entire freeway?
The closure is part of the Hospital Curve rehabilitation project. Caltrans says crews will work continuously to complete reinforced-concrete pavement and other rehabilitation work intended to extend the life of the corridor and improve the road surface.
A second complete northbound closure is scheduled for Sept. 18 through Sept. 21, again beginning Friday night and ending Monday morning.
Should you take BART instead?
For some trips, that may be cleaner. A traveler coming from SFO can take BART into San Francisco without depending on the closed section of Highway 101. Someone coming from elsewhere on the Peninsula may be able to use Caltrain and transfer to local transit, depending on destination and luggage.
Labor Day itself has separate Muni and BART holiday schedules. See our Labor Day parking and transit guide, and our MuniMobile payment guide if you plan to switch modes.
How bad will traffic be?
Nobody can responsibly give an exact delay this far ahead. But this is a complete northbound freeway closure during a three-day holiday weekend, not a one-lane overnight restriction. If you are driving into San Francisco from SFO, the Peninsula or South Bay, check the route before you leave rather than after your navigation app starts rerouting everybody else.