San Mateo County Quarterly Caltrans Update

San Mateo County Quarterly Caltrans Update header banner. Includes a photograph of a stretch of State Route 84 in San Mateo County that travels along a hillside with trees around it.

San Mateo County highways are as diverse as the communities they serve. Situated between the San Francisco Bay to the east and the Pacific Ocean to the west, San Mateo County continues to be an central part of Bay Area infrastructure. With 11 highways and state routes, the 2nd and 3rd longest tunnels in California, and two bridges that span the San Francisco Bay, hundreds of thousands of motorists utilize these facilities each day.


QuickMap

A Driver’s Best Resource on the Highway

Screenshot of Caltrans Quickmaps legend detailing all of the traffic icons and what they represent.Screenshot of Caltrans Quickmaps app of the San Francisco Bay Area region traffic.

Navigating the highways in the Bay Area has it’s challenges. The highways in San Mateo County are no exception. Whether you're commuting to and from the Silicon Valley or making your way towards San Francisco for an eventful outing. We have all experience the impact of busy highways. A great resource for motorists is QuickMap. It is both a mobile app and a website (quickmap.dot.ca.gov) that provides real time traffic information, including road conditions, facility information and resources for commercial vehicles.

A highlight for motorists is the ability to see what lane closures and/or traffic incidents may be along your route. The detailed information allows motorists to make informed decisions as they travel the highways. The listed lane closures provide start and stop times of closures and the listed traffic incidents provide additional information such as which lane the accident ahead is in. This type of information can assist motorists in lessening delays. Please consider checking QuickMap before you drive.

Project Highlights

Near Completion- 2024

Logo of the Woodside Road Construction Project for the Capital Preventative Maintenance (CAPM) project on State Route 84, in San Mateo County, from I-280 to US 101

SR-84 Pavement/ADA Upgrades - State Route 84 in Redwood City and the town of Woodside, San Mateo County. Caltrans started the Woodside Road Construction Project in early March 2024. The project included repaving Woodside Road from I-280 to US 101, upgrading ADA curb ramps, as well as traffic safety enhancements along the corridor such as high-visibility crosswalks for pedestrians and bike facilities. Redwood City in coordination with Caltrans and the County of San Mateo conducted community outreach events including two pop-up events, a survey, and a neighborhood association meeting in November 2023. The majority of noise reducing rubberized asphalt paving and ramp work is complete. Currently, intersection loop detectors are being installed followed by permanent lane striping. Project website

Active

Map showing the project limits of the San Mateo US-101 Pavement Rehabilitation & Median Barrier Upgrade Project. The project is located on US-101 in East Palo Alto, Menlo Park, and Redwood City, from Santa Clara/ San Mateo County line to 0.1 mile south of Whipple Avenue.

US-101 Pavement Rehabilitation & Median Barrier Upgrade Project - This ongoing project will rehabilitate the pavement from Santa Clara/ San Mateo County line to 0.1 mile south of Whipple Avenue (Post Mile 0.0 to 6.5) on 101 throughout the NB and SB mainline. It will also upgrade the median barrier throughout the project limits, replace loop detectors throughout the mainline, update striping, install rumble strips & stripes, and install signs within the project limits. In the interest of reducing impacts to the traveling public, Caltrans is utilizing nine, 55-hour single lane closures to conduct the median barrier upgrade work. As of this newsletter, three weekend single lane closures remain. Weekend closure dates: October 25-28, November 1-4, and November 15-18. Project website

In Design – Construction 2025

Diagram displaying the existing roadway configuration on State Route 82 (El Camino Real) with two lanes of traffic in each direction and trees lining either side of the roadway. 

El Camino Real Roadway Renewal - The El Camino Real Roadway Renewal Project will improve the function, access, and safety of El Camino Real while retaining the character of this critical corridor. The project area stretches 3 miles, between East Santa Inez Avenue and Millbrae Avenue and encompasses uniquely challenging pavement, vegetation, sidewalk, utility, drainage, and safety issues. This stretch of El Camino Real is also lined with heritage tree rows that are listed on the National Register of Historic Places and contribute to the unique character of the corridor. This project is currently in the design phase. Project website

Highways within San Mateo County

Red, white, and blue highway shield for Interstate 280.Interstate 280

Red, white, and blue highway shield for Interstate 380.Interstate 380

Black and white highway shield for U.S. Highway 101.U.S. Route 101

Green and white highway shield for California State Route 1.State Route 1

Green and white highway shield for California State Route 9.State Route 9

Green and white highway shield for California State Route 35.State Route 35

Green and white highway shield for California State Route 82.State Route 82 (El Camino Real)

Green and white highway shield for California State Route 84.State Route 84 (Dumbarton Bridge)

Green and white highway shield for California State Route 92.State Route 92 (San Mateo Bridge)

Green and white highway shield for California State Route 109.State Route 109

Green and white highway shield for California State Route 114.State Route 114

Resources

Have a concern to report? – Customer Service Request
Need information? – Public Affairs
Need to file a claim? – Claims Department
Need roadway conditions? – QuickMap
Connect with Caltrans D4 Bay Area – X (Twitter), Facebook, YouTube

Caltrans Public Information Officer, San Mateo County

Alejandro Lopez
(510) 385-6856
Alejandro.Lopez@dot.ca.gov

District 4 – Bay Area/Oakland

111 Grand Ave
Oakland, CA 94612
(510) 286-4444
caltrans_d4@dot.ca.gov

San Mateo County Facts

  • Founded: April 19, 1856
  • Size: 455 square miles of land, 292 square miles of water
  • Incorporated Cities: 20
  • Coastline: 57.7 miles
  • Population: 729,181 (2022)