Northbound Highway 101 in San Francisco to close again for weekend roadwork. Here's what to know.

A stretch of Highway 101 through San Francisco will again be closed this upcoming weekend as construction crews perform roadwork, officials said.

According to Caltrans, all northbound lanes and one southbound lane of the freeway at Hospital Curve, between Cesar Chavez and 17th streets, will be closed beginning Friday, September 18 at 11 p.m. The closure is scheduled to continue through 6 a.m. on Monday, September 21.

In a statement, the agency said three southbound lanes will remain open throughout the weekend.

The upcoming closure is the second of six scheduled freeway closures to complete major pavement repair work as part of the "Fab 4 Hospital Curve Rehabilitation Project," which began last fall. Caltrans had previously closed the northbound lanes over the Labor Day holiday weekend.

During the upcoming closure, Caltrans is recommending several alternate routes. Drivers headed to downtown San Francisco or the Bay Bridge to the East Bay are urged to take northbound 101 to northbound Interstate 280 into downtown.

To get onto the Bay Bridge from I-280, exit at Sixth Street, make a right turn at Bryant Street and take the on-ramp to eastbound Interstate 80.

Travelers to and from San Francisco International Airport are being encouraged to use Interstate 280 and Interstate 380, avoiding Highway 101 north of the airport.

Caltrans has scheduled two more closures of the freeway at Hospital Curve in the next month. The closures, which will take place between October 2-5 and October 16-19, will impact the southbound lanes, while northbound lanes will remain open.