The County of San Mateo, San Mateo County Transportation Authority, and Caltrans completed the project initiation phase of the Project, resulting in a signed Project Study Report-Project Development Support Report on February 28, 2024. The report is under the “Document and Meeting Materials” section of the webpage below.

Project Overview

The County of San Mateo and the San Mateo County Transportation Authority (TA), in cooperation with the California Department of Transportation (Caltrans), are initiating a project along State Route 1 (SR-1) in Moss Beach.

The goal of this project is to improve traffic flow and safety within the project area, which includes three major intersections: SR-1/16th Street, SR-1/California Avenue, and SR-1/Cypress Avenue. Improvements for the intersections and surrounding project area may include roundabouts, signals, dedicated turn lanes, high-visibility crosswalks, pedestrian walkways, bus stop enhancements, and bike lanes.

To stay aligned with the vision of Connect the Coastside, the project aims to meet the needs of drivers, cyclists, pedestrians, and transit riders, while preserving the character of the coastal community of Moss Beach.

The first phase of this project is "Project Initiation," which was completed on February 28, 2024. The current phase of this project is “Environmental Studies and Project Approval.” Both phases are described further below in the “Project Development Phases” section.

Project Map
Moss Beach State Route 1 Project Map

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For more than a decade, the County of San Mateo has engaged in transportation planning along State Route 1 (SR-1) to identify transportation improvements that meet the unique and complex needs of the County’s midcoast.

In 2009, the County began an intensive community-based planning process along Highway 1 with the Highway 1 Safety and Mobility Improvement Study. The study engaged citizens in developing short- and long-term transportation improvements to better serve pedestrians and people traveling by car and bike in Miramar, El Granada, and Princeton (Phase 1) and in Moss Beach and Montara (Phase 2). The San Mateo County Board of Supervisors adopted Phase 1 and Phase 2 in 2009 and 2012, respectively.

In 2012, the County received $1.5 million in countywide transportation funds to design and permit these congestion-reducing and safety-enhancing projects. The Highway 1 Congestion and Safety Improvement Project Preliminary Planning Study was completed in 2015, which further defined potential improvements.

In 2021, the TA Board of Directors approved a grant (see Item 11b) to support Project Initiation for the Moss Beach SR-1 Congestion and Safety Improvements Project.

In 2022, the San Mateo County Board of Supervisors adopted Connect the Coastside, a plan that's development identified additional potential improvements in the Moss Beach area to better accommodate future transportation needs.

In 2023, the TA Board of Directors approved a grant (see Item 14b on the December 7, 2023 meeting) to support the Project Approval and Environmental Studies phase of the Moss Beach SR-1 Congestion and Safety Improvements Project.

Project Development Phases 

The plans referenced in the Background section above set the vision and need for improvements in Moss Beach. However, to create a "buildable" project and make changes to highways operated by Caltrans, agencies must follow four project development phases. These phases, described below, will be implemented during the Moss Beach project. For additional details, view the publication How Caltrans Builds Projects. The timeline below describes the earliest possible development of the project, assuming available funding.

Project Initiation (Complete)
Project Initiation is the first formal project phase required by Caltrans to move forward with the Moss Beach Highway 1 recommendations identified in Connect the Coastside. During this phase, the project team will establish the purpose and need for the project, study challenges within the project area, identify possible solutions, and estimate the resources needed to complete improvements. Findings from the study are summarized in a Project Initiation Document (PID) and submitted to Caltrans for consideration. A Caltrans' approved PID is required for any major work on the State Highway System and allows the project to be eligible for additional funding. 

The Project Initiation phase began in September 2022 and concluded in February 2024. This phase was funded by the County of San Mateo and with Measure W funds from the San Mateo County Transportation Authority.

Environmental Studies and Project Approval (Current Phase)
The second step is for the project team to perform preliminary design work and conduct environmental studies to analyze the effect and impact of the project alternatives. These studies are required by state and federal laws under the California Environmental Quality Act (CEQA) and the National Environmental Policy Act (NEPA). Potential impacts on a range of subjects such as water quality, plants and animals, and transportation are evaluated during this phase.

The studies result in an Environmental Document (ED) which forms the basis for selecting the preferred alternative. The Draft ED is circulated for public comment, after which it is finalized and approved.

The Environmental Studies and Project Approval phase is anticipated to begin in summer 2024 and conclude in 2026. This phase is funded by the County of San Mateo and with Measure W funds from the San Mateo County Transportation Authority.

Project Design and Right-of-Way
The third step is for the project team to prepare the detailed project design on the approved alternative. This phase is called Plans, Specifications, and Estimates (PS&E). Project information is reviewed and updated, an alternative is selected, and design and engineering reports are generated. Plans for any structures are also prepared. During this phase, any necessary permits and approvals are also coordinated such as a coastal development permit.

Final right-of-way requirements are determined and procurement is initiated during PS&E.  At the completion of the PS&E phase, a complete set of project plans are provided to allow a contractor to bid and build the project.

The construction phase of the project entails building the improvements as shown on the plans. The contractor’s work is overseen by construction inspectors and a Caltrans engineer. Care is taken to protect existing resources and minimize impacts during construction.

Project Timeline
Moss Beach Updated Timeline Graphic (3-29-24)
Upcoming Events

Please check back for additional events and join our project mailing list below for additional updates.

Documents and Meeting Materials

Technical Documents:

Engagement Documents:

Related Studies, Plans, and Policies:

Project Initiation Phase Transportation Authority Grant:

Project Approval and Environmental Studies Phase Transportation Authority Grant:

Contact Us

Sign up to receive email updates or send comments to the project team:

Chanda Singh, Senior Transportation Planner, County of San Mateo

Lilliana Price, Project Manager, San Mateo County Transportation Authority

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