Proposed Project Initial Study with Proposed Negative Declaration Recirculation Background Information


The California Department of Transportation (Caltrans) proposes to install six wireless detection systems (WDS), five ground mounted variable message signs (VMS), Midwest guardrail systems (MGS), and maintenance vehicle pullouts (MVP) on State Route (SR) 1 in San Mateo County from the Miramontes Point Road Intersection to the Clarinada Avenue Undercrossing. The project would also update software at an existing changeable message sign (CMS) at the entrance to the Tom Lantos Tunnels at Devil’s Slide. The total length of the project is approximately 20.9 miles. The proposed project would occur in San Mateo County on SR 1 from postmile 26.43 to 47.20.


Caltrans prepared a CEQA IS with an ND document and circulated it for public review on August 14, 2020. A virtual public meeting was held on September 10, 2020. As a result of the comments received and consultation with the local communities, the project’s design was reviewed and revised with respect to the use and locations of the signs system. This included changing the proposed use of the signs for displaying general travel time information to a focus on providing information related to emergencies—such as floods, mudslides, wildfire, and resulting evacuations—power safety shutoffs, accidents, road closures or construction, or other events that could result in substantial delays where drivers would benefit from timely information.

The proposed signs would be activated during emergencies or incidents only and would be off most of the time. The signs would only be programed to be lighted when needed to convey emergency and incident-related information to motorists. In addition, some of the VMS locations were reviewed and relocated in response to public review and input. In response to concerns expressed over the visual impacts associated with the signs, Caltrans reviewed and identified new locations for the proposed signs at locations 5, 6, and 9.

Placement of signs at the revised locations would still serve the purpose of the project and would result in reduced visual impacts from the VMS. Location 2—adjacent to a car dealership in Half Moon Bay—was also considered for relocation, but after a detailed review, Caltrans determined that there were no other locations that served the project’s purpose. The location would place the VMS before the SR 1 and 92 intersection, making it possible for motorists to safely turn around in the case of an emergency. Furthermore, Caltrans considered the possibility of reducing the size of the VMS panels. Caltrans determined that the size could not be reduced because a reduction in size of the panel would not be large enough to effectively deliver useful messaging on emergencies and incidents to the traveling public. VMS proposed for the project would be approximately 12 feet wide by 5 feet tall.

Because the proposed project was revised to focus on emergency and incident-related messaging and some sign locations were modified, Caltrans decided to recirculate this document. This IS and ND has been updated based on these changes, and additional information has been provided on the appearance of the signs, including visual simulations of the signs and proposed changes. The comments that were received during the review period in 2020 were considered in making changes to the project, and a summary of coordination with external stakeholders is provided in Chapter 3.

Project picture