Devil's Slide Improvement Project

Route 1 from Half Moon Bay Airport to Linda Mar Boulevard in Pacifica,

San Mateo County, California





Robert Gross, Chief
Office of Environmental Planning, South
Caltrans District 4
P.O. Box 23660
Oakland, CA 94623-0660




The 1986 Devil’s Slide Final Environmental Impact Statement (FEIS) included a section on History which included a chronology of events and activities related to attempts at resolving the problems at Devil’s Slide from 1951 to February 1986. Refer to the 1986 FEIS (pp. 15-25) for the prior history and specific chronological events for that period.

The following is a more general history of the Devil’s Slide project in a narrative format and for the period of late 1983 to the present.

Caltrans and the Federal Highway Administration (FHWA) circulated a draft Environmental Impact Statement (EIS) in December 1983, for a proposal to improve State Route 1 in San Mateo County, California. The project study limits of alternatives considered in the document extended from Half Moon Bay Airport, between Moss Beach and El Granada, on the south to Linda Mar Boulevard in Pacifica on the north, a distance of approximately 11.3 km (7 miles). As part of the public review process, Caltrans conducted a public hearing on the draft EIS on January 12, 1984.

The San Mateo County Planning Commission and the City of Pacifica each also held a public hearing on the draft EIS during the following weeks. In late January and early February 1984, the San Mateo County Planning Commission, the City of Pacifica, and the City of Half Moon Bay each selected a different alternative as their "preferred" alternative. The San Mateo County Board of Supervisors held a public hearing on the draft EIS on February 14, 1984 in Half Moon Bay and selected their preferred alternative on March 6, 1984. The County Board of Supervisors in April 1984 rescinded their previous action regarding their preferred alternative and approved the concept of an inland bypass with the alignment and design option to be identified after Caltrans submittal of the Final Environmental Impact Report (EIR) to the Board.

On January 3, 1985, a Final EIR was certified by Caltrans and distributed on January 16, 1985. The "adopted alignment", a 6.8 mile route between Half Moon Bay airport and Linda Mar Boulevard in Pacifica, was identified as the preferred alternative. This was followed by multiple reviews and public hearings conducted by the San Mateo County Board of Supervisors and the California Coastal Commission regarding the various project alternatives and whether they were consistent with the certified Local Coastal Program (LCP) and the Coastal Act. Additional public hearings regarding amendments to the LCP were conducted and several attempts to certify these amendments failed when the Commission’s action resulted in tie votes.

On October 8, 1985, Caltrans announced to the Board of Supervisors that the preferred alternative would be modified to what was to be referred to as the Martini Creek Alignment.

A Supplemental Environmental Impact Report (SEIR) which discussed this modified Martini Creek Alignment Alternative was distributed on November 15, 1985.

The City of Pacifica on December 9, 1985 and the San Mateo County Board of Supervisors on December 12, 1985 each held a public hearing on the draft-SEIR. The California Coastal Commission on February 11, 1986 determined that the Preferred Alternative known as the Martini Creek Alignment alternative was consistent with the Coastal Zone Management Program.

The final EIS (FEIS) was approved by FHWA on April 16, 1986. The Martini Creek Alignment alternative was selected by FHWA for project construction in the Record of Decision (ROD) on May 30, 1986.

Litigation regarding the project was commenced in U.S. District Court in the Northern District of California in June 1986 (Sierra Club, et al. v. United States Department of Transportation, et al., Civ. No. 86-3384 DLJ). The project has been enjoined since September 1986, prior to the commencement of any construction. Ultimately, the District Court found that the 1986 FEIS was inadequate only in its discussion and analysis of noise impacts and required a re-analysis of those impacts, as set forth in the Court's Orders of April 3, 1989, and April 2, 1990. Thereafter, in March 1995, FHWA and Caltrans prepared a draft supplemental EIS/R (SEIS/R) for the purpose of addressing the noise impact analysis deficiencies of the 1986 FEIS, as determined in the litigation.

Public comments on the 1995 SEIS/R called for consideration of a tunnel alternative, and the August 10, 1995 Record of Decision for the Devil’s Slide Project included a commitment by the FHWA to address the issue of a tunnel alternative in the reevaluation of the 1986 FEIS. A tunnel alternative had been considered earlier in the project development process, but had been withdrawn from active consideration prior to the issuance of the 1983 draft EIS. The reevaluation was to be undertaken since major steps to advance the project had not occurred within three years after the approval of the FEIS (23 C.F.R. Sec. 771.129(b)).

In 1996, in response to requests from local agencies and the public, Caltrans hired an independent consulting firm to conduct a tunnel feasibility study. Based upon the results of "The Devil’s Slide Tunnel Study" (Woodward-Clyde Consultants, 1996), and the updated cost estimates for the revised Martini Creek alignment alternative (now $112 million), FHWA and Caltrans determined that a tunnel alternative is, in fact, a reasonable alternative for the proposed project that should be fully evaluated in the environmental process. Therefore, Caltrans and FHWA determined that a new supplement to the 1986 FEIS was necessary in order to provide new information relevant to the tunnel alternative. Based on the decision to supplement and update the 1986 FEIS, a separate reevaluation of the 1986 FEIS was no longer necessary.

In addition, on November 5, 1996, the voters of San Mateo County passed the Devil’s Slide Tunnel Initiative known as Measure T. Passage of the Measure initiated the process to amend the County’s land use plan portion of the San Mateo County certified LCP to provide a tunnel for motorized vehicles only behind Devil’s Slide through San Pedro Mountain as the preferred alternative for Highway 1 around Devil's Slide, and to delete references to a two-lane highway bypass along the Martini Creek alignment. The Initiative requires that the tunnel be designed consistent with restricting Route 1 to a two-lane scenic highway using minimum state and federal tunnel standards, and that a separate trail for pedestrians and bicycles be provided outside the tunnel. The Measure also requires voter approval of any other alternative to the tunnel, except repair of the existing highway. On January 9, 1997, the California Coastal Commission voted to certify the LCP amendment as submitted by the County.



This second supplemental Environmental Impact Statement/Report (SEIS/R) supplements the 1986 FEIS and the 1985 FEIR. With the exception of background information provided for clarity, this document and the 1995 Final SEIS contain that information necessary to make the 1986 FEIS adequate for the project, in terms of providing necessary information to the public, interested entities, and decision makers.

As set forth in Part 771 of Title 23 of the Code of Federal Regulations regarding Environmental Impact and Related Procedures:

' 771.130. Supplemental environmental impact statements:

(a) A draft EIS, final EIS, or supplemental EIS may be supplemented at any time. An EIS shall be supplemented whenever the Administration determines that:

(1) Changes to the proposed action would result in significant environmental impacts that were not evaluated in the EIS; or

(2) New information or circumstances relevant to environmental concerns and bearing on the proposed action or its impacts would result in significant environmental impacts not evaluated in the EIS.

As stated in Section 15163(c) of the California Environmental Quality Act (CEQA) guidelines:

(a) The Lead or Responsible Agency may choose to prepare a supplement to an EIR rather than a subsequent EIR if:

(1) Any of the conditions described in Section 15162 would require the preparation of a subsequent EIR, and

(2) Only minor additions or changes would be necessary to make the previous EIR adequately apply to the project in the changed situation.

(b) The supplement to the EIR need contain only the information necessary to make the previous EIR adequate for the project as revised.

(c) A supplement to an EIR shall be given the same kind of notice and public review as is given to a draft EIR under Section 15087.

(d) A supplement to an EIR may be circulated by itself without recirculating the previous draft or final EIR.

(e) When the agency decides whether to approve the project, the decision-making body shall consider the previous EIR as revised by the supplemental EIR. A finding under Section 15091 shall be made for each significant effect shown in the previous EIR as revised.

This second SEIS/R presents "new information or circumstances relevant to environmental concerns and bearing on the proposed action" as per Section 771.130(a)(2) stated above.

In accordance with the National Environmental Policy Act (NEPA), a supplement to a FEIS may be circulated by itself without re-circulating the original document. Pursuant to ' 771.130 of the Federal Highway Administration Regulations governing the preparation of EIS’s and Section 15163(c) of the California Environmental Quality Act (CEQA) guidelines, revised December 1991, this supplement will be given the same kind of notice and public review as was the 1983 draft EIS and EIR and the 1995 draft SEIS/R. For project information beyond that addressed in this draft SEIS/R, the reader is referred to the 1986 FEIS and the 1995 SEIS/R.

Copies of the 1986 FEIS, the 1995 final SEIS/R and this 1998 draft SEIS/R are available for public viewing at the locations listed on the following page. These documents are also available for public viewing between the hours of 8:00 AM and 5:00 PM at the Caltrans District 4 Office of Public Affairs on the first floor at 111 Grand Avenue, Oakland, California. Copies of the technical studies identified in Section 10 of this document are also available for review at the Caltrans District 4 Office in Oakland, the City of Half Moon Bay City Hall, and the City of Pacifica City Hall. Copies of the references identified in Section 11 are available for review at the Caltrans District 4 Office in Oakland. Comments received on this draft second SEIS/R will be addressed in the final second SEIS/R.





Public Review Locations


San Mateo County

Planning Department

455 County Center

Redwood City, CA 94063

San Mateo County

Transportation Authority

1250 San Carlos Ave.

San Carlos, CA 94070


City of Pacifica

City Hall

170 Santa Maria Avenue

Pacifica, CA 94044


City of Half Moon Bay

City Hall

501 Main Street

Half Moon Bay, CA 94019


Pacifica Public Library

Hilton Way And Palmetto Avenue

Pacifica, CA 94044


Half Moon Bay Library

620 Correas Avenue

Half Moon Bay, CA 94019


Pacifica Chamber of Commerce

450 Dondee Way, Suite 2

Pacifica, CA 94044


Half Moon Bay Chamber of Commerce

520 Kelly Avenue

Half Moon Bay, CA 94019


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