San Francisco drivers heading south this weekend will need a different plan at Hospital Curve, where a full southbound US 101 closure overlaps with separate northbound I-280 lane reductions.

Caltrans has confirmed the work for October 16–19, 2026, but the two freeways have different schedules and restrictions.

US 101: Friday night through Monday morning

All southbound US 101 lanes between 17th Street and Cesar Chavez Street are scheduled to close from 11 p.m. Friday, October 16, until 6 a.m. Monday, October 19.

One northbound lane will also close, with the remaining northbound lanes staying open.

The agency’s October 9 advisory says crews will repave the southbound roadway and begin grinding the repaved northbound surface to improve smoothness.

This is the third closure weekend in the Hospital Curve rehabilitation project, which began in fall 2025.

A fourth closure is scheduled for November 6–9, weather permitting; that November work replaced an earlier October 2–5 date.

For this weekend, the useful takeaway is the direction of travel: a northbound lane reduction and a southbound shutdown require different route choices.

I-280: two overnight bottlenecks

Between Mariposa Street and the I-280/US 101 interchange, two northbound I-280 lanes will close, leaving one lane available.

The first window runs from 10 p.m. Friday, October 16, to 9 a.m. Saturday, October 17.

The second runs from 10 p.m. Saturday, October 17, to 10 a.m. Sunday, October 18.

Use those exact times: although the October 12 advisory describes two 12-hour closures, its first listed window is 11 hours.

All southbound I-280 lanes remain open, making that freeway the alternative Caltrans recommends for southbound US 101 traffic.

Crews will finish placing polyester concrete to improve pavement durability and ride quality.

The agency advises additional travel time and public transit or alternate highways where possible, but does not specify a street-by-street northbound I-280 detour in that notice.

Which connectors and ramps close?

Caltrans’ Hospital Curve detour page lists closures of the westbound I-80-to-northbound US 101 connector and the southbound Central Freeway-to-southbound US 101 connector/mainline.

It also lists the westbound I-80 Fourth and Seventh Street on-ramps, eastbound I-80 Seventh Street off-ramp for trucking, and northbound US 101 Tenth Street on-ramp.

These access restrictions matter even if your usual trip does not cross the entire paving segment.

From westbound I-80, one posted detour exits at Fifth Street, follows Harrison Street to Sixth Street, turns left, and uses the southbound I-280 on-ramp.

Drivers can continue southbound I-280 to southbound US 101, or exit at Pennsylvania Avenue, turn right onto Cesar Chavez Street, and enter southbound US 101 there.

Another posted option takes the Eighth Street exit, signed Ninth Street, follows Harrison to Tenth, turns left, continues onto Potrero, and uses the southbound US 101 on-ramp.

Follow posted signs and the official detour map for the route appropriate to your approach.

Before leaving home

Check Caltrans’ current project notices and QuickMap immediately before departure, especially for airport trips, deliveries or appointments with a fixed arrival time.

Allow a buffer without assuming a specific delay; the notices do not provide a reliable extra-minutes estimate.

Keep the Monday 6 a.m. reopening in mind when planning an early commute.

Schedules can change, and an announced reopening time is a plan rather than a guarantee.

Reporting checked October 13; recheck the linked Caltrans advisories before the Thursday, October 15 publication target.

Official sources: US 101 advisory; I-280 advisory; Hospital Curve detours; Caltrans project updates; QuickMap.