Peninsula drivers should plan for intermittent closures on U.S. 101 for the rest of the month. Caltrans says crews will close lanes and ramps at various times in both directions between South San Francisco and East Palo Alto through Friday, Oct. 30, and the San Mateo Police Department has passed the advisory along to residents.
When the closures happen
Most of the work happens at night. Caltrans has scheduled intermittent lane and ramp closures from 9 p.m. to 5 a.m. on weeknights, northbound and southbound, from Oct. 5 through Oct. 30. There is daytime work too: partial ramp closures between 7 a.m. and 3 p.m. so crews can rebuild curb ramps within the project area.
The closures are intermittent, so not every lane or ramp will be shut for the whole period. Caltrans also says all of the work depends on the weather, which means the schedule can shift if storms arrive. People who live or work near the freeway may hear construction noise during work hours.
What crews are doing
This phase covers paving, guardrail, drainage and electrical work. It is part of the larger U.S. 101 Multi-Asset Rehabilitation and Roadside Safety Project, a $177 million effort that runs the full length of the county, from its northern border in South San Francisco to its southern border in East Palo Alto. Besides paving and guardrails, the project includes upgrades to drainage, the traffic management system and curb ramps that meet Americans with Disabilities Act standards.
The money comes from the State Highway Operation and Protection Program, which Caltrans describes as a fix-it-first program for repairing and preserving existing highways. Construction began in March 2026 and is scheduled to wrap up in December 2027, so this month's closures are one of several rounds; Caltrans posted similar closure notices in March, April, May, June and September.
Planning your trip
Police are asking drivers to allow extra time, slow down approaching work zones and stay alert around crews. Caltrans recommends checking its QuickMap site or 511.org for current closures before heading out, and statewide highway conditions are available by phone at 1-800-427-7623.