SM 101 Express Lanes Project


Active Dates - Feb 2020 - 2022

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Project History

In 2019, Caltrans broke ground on its multi-year, multi-agency San Mateo 101 Express Lanes Project, which aims to reduce traffic congestion and encourage carpooling and transit use on U.S. Highway 101 in San Mateo County. The project will create 22 miles of express lanes on U.S. Highway 101 from I-380 in San Bruno to the San Mateo County/Santa Clara County border. The San Mateo 101 Express Lanes will then seamlessly connect to the express lanes being constructed in Santa Clara County. 

Public Works Department staff coordinated with Caltrans on the relocation of three sections of sound wall adjacent to northbound US Highway 101. The sound walls will be reconstructed at their existing lengths and heights.

At public meetings in San Mateo in late 2018, the City and residents aired concerns about potential noise issues due to the wall moves. The project’s Environmental Assessment reported that the project will cause a negligible increase in noise for this area. Click here for the Noise Analysis Fact Sheet

On June 17, 2019, Caltrans presented an update to the project to San Mateo City Council. To see its presentation, click here to watch the video (starts about 2:48). In December 2019, Caltrans returned to our City for an update on the project. Watch that update here. 

Proposed Replacement Sound Walls

Below are the three replacement sound walls under reconstruction. Construction began in our city in early 2020. 

Location 1SM 101 Express Lanes Replacement Sound Wall Location 1 

Location 2SM 101 Express Lanes Replacement Sound Wall Location 2

Location 3
SM 101 Express Lanes Replacement Sound Wall Location 3