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Open House for the Moss Beach State Route 1 Congestion & Safety Improvements Project

September 19th, 2023 @ 6:00pm - 8:00pm

Mark your calendars!

On Tuesday, September 19, the San Mateo County Transportation Authority will be hosting an open house to showcase proposed improvements along Highway 1 in Moss Beach. We hope to see you there!

Learn more at smcgov.org/planning/Moss-Beach-SR-1 


The Moss Beach SR-1 Congestion & Safety Improvements Project aims to improve traffic flow and safety on State Route 1 from 16th Street to Cypress Avenue, which includes three major intersections: SR-1/16th Street, SR-1/California Avenue, and SR-1/Cypress Avenue. The project aims to improve safety and accessibility for drivers, cyclists, pedestrians, and transit riders, with careful consideration given to preserving the character of Moss Beach’s unique coastal community.


Learn more about the project and sign up for updates at the

project webpage.


Open House Tuesday, Sept 19, 2023 from 6 – 8 PM
SMC District 3 Coastside Office, Harbor Village,
270 Capistrano Rd #6, Princeton


Can’t attend?

Special exhibit showcasing project design concepts will remain open for 3 days, to drop by at your own convenience Sept 19 – 21 from 9 – 5 PM.




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 and current phase of this project is “Project Initiation,” described further below in the “Project Development Phases” section.




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.

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 (Current Phase)

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 is expected to conclude in November 2023. This phase is funded by the County of San Mateo and with Measure W funds from the San Mateo County Transportation Authority.


Environmental Studies and Project Approval
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.


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


Upcoming Events

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



Engagement Documents:


Related studies, plans, and policies:


Project Initiation Phase Transportation Authority grant:

Contact Us

For questions about this project, please contact:

Chanda Singh, Senior Transportation Planner, County of San Mateo

Katie Faulkner, Planner III, County of San Mateo

Lilliana Price, Project Manager, San Mateo County Transportation Authority


September 19th, 2023
6:00pm - 8:00pm
Event Categories:
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Supervisor Ray Mueller’s Office
270 Capistrano, Suite 6
Half Moon Bay, CA 94019 United States
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